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FHWA Report No. FHWA-RD-99-146
Materials and Procedures for Repair of Joint Seals in Portland Cement Concrete Pavements
Manual of Practice
Federal Highway Administration U.S. Department of Transportation
Strategic Highway Research Program National Research Council
FOREWORD This manual (FHWA-RD-99-146) is an update of the Strategic Highway Research Program (SHRP) manual of practice (SHRP-H-349) on concrete pavement repair. The Federal Highway Administration, Long Term Pavement Performance Program (LTPP) conducted five years of additional research on concrete pavement repair after the conclusion of SHRP. This research validated the repair procedures contained in the original SHRP manual. The manual presents updated guidelines and recommendations to assist highway maintenance agencies and other related organizations in planning, constructing, and monitoring the performance of concrete pavement joint resealing projects. Included in the manual are discussions pertaining to when joint resealing is appropriate, the types of sealant materials and construction methods that should be used, how each individual step in a joint resealing operation should be performed, and how the performance and costeffectiveness of joint seals can be evaluated. This report will be of interest and benefit to various levels of agency maintenance personnel, from crew supervisors to the chief maintenance engineer.
NOTICE This document is disseminated under the sponsorship of the Department of Transportation in the interest of information exchange. The United States Government assumes no liability for its contents or use thereof. This report does not constitute a standard, specification, or regulation. The United States Government does not endorse products or manufacturers. Trade and manufacturers'names appear in this report only because they are considered essential to the object of the document.
Technical Report Documentation Page
1. Report No. 2. Government Accession No. 3. Recipient's Catalog No.
4. Title and Subtitle 5. Report Date 6. Performing Organization Code
Materials and Procedures for Repair of Joint Seals in Portland Cement Concrete Pavements---Manual of Practice
8. Performing Organization Report No. 7. Author(s)
L.D. Evans, K.L. Smith, and A.R. Romine
9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) 11. Contract or Grant No.
ERES Consultants A Division of Applied Research Associates, Inc. 505 W. University Avenue Champaign, IL 61820-3915
12. Sponsoring Agency Name and Address
13. Type of Report and Period Covered
Federal Highway Administration Pavement Performance Division 6300 Georgetown Pike McLean, Virginia 22101
15. Supplementary Notes
Updated Manual of Practice October 1993 - June 1999
14. Sponsoring Agency Code
FHWA Contracting Officer's Technical Representative (COTR): Shahed Rowshan, HRDI Project Consultants: Charlie Smyth
16. Abstract
The Strategic Highway Research Program (SHRP) H-106 maintenance experiment and the Federal Highway Administration (FHWA) Long-Term Monitoring (LTM) of Pavement Maintenance Materials Test Sites project studied the resealing of joints in concrete pavements. Many different sealant materials and resealing methods were investigated between 1991 and 1998 through test sites installed at five locations in the United States. The findings of these combined studies have been merged with standard highway agency procedures to provide the most useful and up-to-date information on the practice of concrete joint resealing. This Manual of Practice is an updated version of the 1993 SHRP Joint Seal Repair Manual. It contains the latest information pertaining to the performance of sealants and resealing methods, the availability and relative costs of sealant materials, and the proper ways of planning, designing, constructing, and monitoring the performance of joint resealing projects. It also provides an updated partial listing of material and equipment manufacturers. This Manual is intended for field and office personnel within highway maintenance agencies and contracted maintenance firms. It contains valuable information for supervisors and foremen in charge of individual resealing operations, engineers in charge of planning and overseeing many joint resealing projects, and managers in charge of establishing resealing policies and standards.
17. Key Words
18. Distribution Statement
Concrete pavement, pavement maintenance, joints, joint resealing, joint sealant, joint reservoir, performance, effectiveness, cost-effectiveness
No restrictions. This document is available to the public through the National Technical Information Service, Springfield, Virginia 22161.
19. Security Classif. (of this report)
20. Security Classif. (of this page)
21. No of Pages
22. Price
Form DOT F 1700.7 (8-72)
Reproduction of completed page authorized
many different test sections were installed and evaluated to determine the cost-effectiveness of maintenance materials and procedures. Test sections were installed at 22 sites throughout the United States and Canada between March 1991 and February 1992. iii . the repairs and treatments were evaluated annually through the end of 1997. 1991). Under the Long-Term Monitoring (LTM) of Pavement Maintenance Materials Test Sites project. beginning in October 1993. Following the conclusion of SHRP H-106 in 1993. The information and findings from that study were then used in the subsequent field experiments conducted under SHRP project H-106.. Innovative Materials Development and Testing. under the supervision of SHRP representatives. the FHWA sponsored a study to continue monitoring the performance of the experimental repairs and treatments. In SHRP project H-105.TECHNOLOGIES HOME PRINT BOOKMARKS Preface This manual is intended for use by highway maintenance agencies and contracted maintenance firms in the field and in the office. Innovative Materials and Equipment for Pavement Surface Repair. In project H-106. The researchers collected installation and productivity information at each site and periodically evaluated the experimental repairs and treatments through the end of 1992. The first version of this manual was prepared in October 1993 and was based on this work effort. the researchers conducted a massive literature review and a nationwide survey of highway agencies to identify potentially cost-effective pavement repair and treatment options (Smith et al. It is a compendium of good practices for portland cement concrete (PCC) joint resealing operations. stemming from the Strategic Highway Research Program (SHRP) pavement maintenance studies and a follow-up study sponsored by the Federal Highway Administration (FHWA).
Readers who want more information on topics included in this manual should refer to the reference list provided at the back.TECHNOLOGIES HOME PRINT BOOKMARKS Pertinent long-term performance and cost-effectiveness information generated by the continued monitoring of the experimental joint resealing treatments has been included in this revised manual. iv . The final report for the H-106/LTM portland cement concrete (PCC) joint resealing study may be of particular interest to many readers (Evans et al. and field performance of each joint resealing treatment type investigated. For the reader's convenience. It details the installation procedures.. laboratory testing of the materials. potentially unfamiliar terms are italicized at their first occurrence in the manual and are defined in a glossary. 1999).
SHRP was a unit of the National Research Council that was authorized by section 128 of the Surface Transportation and Uniform Relocation Assistance Act of 1987. Mike Belangie. David Peshkin. and to the following State highway agencies: ! ! ! ! ! Arizona Department of Transportation Colorado Department of Highways Iowa Department of Transportation Kentucky Transportation Cabinet South Carolina Department of Highways and Public Transportation The contributions of the following individuals are also acknowledged: Michael Darter. Special thanks are due the project management teams at SHRP and the FHWA. Charlie Smythe. v . Henry Bankie. and Jim Chehovits.TECHNOLOGIES HOME PRINT BOOKMARKS Acknowledgments The research described herein was supported by the Strategic Highway Research Program and the Federal Highway Administration. Sam Carpenter.
. . . . . . . . . . 13 3. . .1 Primary Considerations . . . . . . . . . . . .0 Need for Joint Resealing . . . . . . .3 Environmental Conditions . .5 Determining the Need to Reseal . . . . . . . . . . . . . . 15 3. . . . . . . 9 2.9. 22 3. . . . . . . . . . . . . . . . . 26 3. . . . . . . . . . . . . . . . 32 3. . . . . . . . . . . . . . . . . . . . 16 3. . . . . .9 Selecting Equipment . . and Equipment Requirements . . . . . . .1 Scope of Manual . . 3 2. . 2 2. . . . . . . .6 Selecting Primer Materials . . . . . . . . . . . Labor.8 Silicone Sealant Applicators . . . . . . .5 Hot Airblasting Equipment . . . . . . . . . . . . . . . . 29 3. .9. . . . .4 Airblasting Equipment . . . . . . . . . . . 29 3. . . . . 36 3.9 Other Equipment . . . . . . . . . . . . . . . . . . . .5 Selecting Backer Materials . . . . . . . . . . 21 3. . . .4 Traffic Conditions . . . . . . . . . . . . . . 36 3. . 33 3. . .7 Hot-Applied Sealant Installation Equipment . . . . . 39 vii . . . . . . .2 Overview . 15 3. .8 Selecting Preparation and Installation Procedures . . . . . . . . . 37 3. . . .9. . 11 2. . . . . .2 Objective of Resealing . . . . . . . .9. . . . . . . . . . . . . . .1 Joint Plows . . . . .4 Selecting a Sealant Material Type . . . . . . . . . . . . . . . . . . . . . .0 Planning and Design . .9. . 15 3. . . . . . .9. . . . . . . .10 Estimating Material. .9. . . . . . 17 3. . 34 3. . . . . . . . . . . . . . . . . .3 Accounting for Existing Conditions . . . . . . . . . . . 38 3. . . . . . .1 Seal Condition . . . . . . . . . . .0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . .2 Pavement Condition . . . . .9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TECHNOLOGIES HOME PRINT BOOKMARKS Contents 1.7 Selecting Joint Reservoir Dimensions . . . . . . .9. . 1 1. . . . . . . . . . . 3 2. 1 1. 39 3. . . . . . . . . . . . . . . . . .6 Backer Rod Installation Tools . . .3 Abrasive Blasting Equipment . . . . . . . .2 Concrete Saws . 12 2. . 20 3.
. .0 Construction . . . .4 Airblasting the Joint Reservoir . . . . . . . . . .4 User Delay Costs . . . . . . . . .11 Determining Cost-Effectiveness . . . . . . . . . . . . 60 4. . . . 77 Appendix A Material Testing Specifications . . . . 41 3. . . . . . . . . . . . . . . . . . . 45 4. . . . .3. . . . . . . . . . . . . . . 48 4. . . . . . .11. . . . . . . . 89 C. . . . . . . . . . . 48 4. . . . . . . . . . 51 4. . . . . .1 Material and Shipping Costs .2 Safety Precautions . . . . . . 79 Appendix B Sample Cost-Effectiveness Calculations . . . . . .11. . .1 Removing the Old Sealant . . . . .1. . . . . . .1. . . . . . . 43 3. . . . . .5 Cost-Effectiveness Comparisons . . .3. . . . . . 83 Appendix C Material and Equipment Safety Precautions . . .11.0 Evaluation of Joint Seal Performance . . . . . . . . . Hot-Applied Sealants . . . .3 Preparing the Joint . . . . . .1 Traffic Control . .3 Equipment Costs . . . . . 47 4. . . .3. 90 viii . 53 4. . . . . . . .2. . . . . . . . . . . . . . . . 47 4. . . . . . . . . Cold-Applied Sealants .5 Installing Primer . . . . . . . . . . . . . . . . 41 3. . .3 Abrasive Blasting the Joint Sidewalls . . . . . 47 4. .4. . . . . . . . . . . . . . . . 43 3. . .4. . .1. . .4 Material Preparation and Installation . . . . . . .3. . . . . . . .11. . .11. Materials . . . 63 5. . . . . . . . . . . . . . . 89 C. . 59 4. . 56 4. . . . . . . . . .2 Sealant Installation . . .TECHNOLOGIES HOME PRINT BOOKMARKS 3. . . .1 Installing Backer Rod . . . . .3. . . . . . . . . . . . . . . . .1. . 89 C. . . . . . 59 4. . . . . . 43 3.2 Refacing the Joint Sidewalls . .2 Labor Costs . .
. . . . . . . . . . . . . . D. . Manufacturers of Self-Leveling and Non-Self-Leveling Silicone Sealant .2. . 103 E. . . . . . . . . . . . . . Manufacturers of Expanded ClosedCell Foam Rod . . .3. . .3. . . . . . . . . . . . . . . . . . . Manufacturers of Pump Applicators For Cold-Applied Sealants . . . . . . . . . . .3. . . . . . Inspection of Joint Sealant Installation . .2. . . . . . . . 107 References . . . . 104 E. . Manufacturers of Melter–Applicators For Hot-Applied Sealants . . . . . . .3. . . . . . . . . .2. . Inspection of Joint Preparation . .3. . .4. . . . . . 91 Equipment Inspection . . .TECHNOLOGIES HOME PRINT BOOKMARKS Appendix D D. . . . . 98 Final Inspection . . . . . . . . .1 D. . . . . . . . 105 E.2. . . . . . Sealant Installation Equipment . . 101 Appendix E Partial List of Material and Equipment Sources .1. . . . . .1. .1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Field Installation Inspection . . . . . . . . . . . . . . . . . . . . . . . . .1. . . . . .1. . 91 Preconstruction Plans and Specifications .2. . . .3. .1. 105 E. . . . . . . . . 105 Glossary . . . . . . . . . Backer Rod Material . . . . . . . . . 104 E. . . . . . . . 103 E. . . . Manufacturers of Hot-Applied Rubberized Asphalt Sealant . . . 104 E.1. . . . . Sealant Material . . Inspection Checklists for Construction . . . . 111 ix . D. . . . . 94 D. . . . .2. . 103 E. . . . . . . . . 94 D. . . .
. . . . . 4 Sealant adhesion failure . . . . . 7 Full-depth cohesion failure . . . . . . . . . . . . . . . 34 Airblasting operation . . 7 Typical joint cross section . Figure 10. . . . . .TECHNOLOGIES HOME PRINT BOOKMARKS Figures Figure 1. . . Figure 7. . . . . . . . . . . . . . . . . . 31 Concrete joint saw . Figure 13. . . . . Figure 9. . . . . . 67 Silicone sealant installation . . . . . . 55 Airblasting operation . . . . . . . Figure 19. Figure 12. . . . . . . . . . . . . . . 32 Abrasive blasting equipment . . 50 Joint resawing operation . . . . Figure 16. Figure 8. . . . . . . . . . . . . . . . Figure 15. . . . Figure 11. . . . . . . . . . . . . . . . . . . . . . Concrete pavement/joint survey form . . . . . . . . . . 31 Undercarriage-mounted joint plow . . . Figure 6. . . . 57 Backer rod installation . . . 35 Hand-operated backer rod installation tool . . . . . . . . . . . 52 Abrasive blasting operation . . . . . Figure 2. . . . . . 37 Joint plowing operation . . . . . . . . . . . 62 Hot-applied sealant installation . . Figure 17. . Figure 14. . . . . 36 Automated backer rod installation tool . . Figure 4. 23 Rear-mounted joint plow . . . . . . . . . . . 72 Example joint seal deterioration chart . . . . . . . Figure 3. . . 78 xi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 18. . . . . . . . . . . . . . . . . . . . . . Figure 5. .
. . . . . . . . . . . . . . . 12 Traffic-level rating . Table 3. . . 21 Typical recommended shape factors . . . . . . . . . Table 2. . 18 Summary of sealant materials . . . . . . . . . . . . . . . . Table 11. . . . . 5 Climatic region parameters . . . . . . 13 Relationship between pavement condition and sealing objectives . . . . . . . . . . 25 Joint preparation/installation procedures . . Table 6. . . . 27 Joint resealing equipment requirements . . . . . . . . . 42 Labor costs . Table 14. . . 23 Typical joint design dimensions . . . . Table 10. . . . . Decision table for resealing PCC joints . . . . . . . . . . . . . Table 18. . . . . . . Table 12. . 44 Cost-effectiveness worksheet . . . . . . . . and amounts . . . . . . . . . . . . 44 Equipment costs . Table 7. . . . . . . . . . . . . . . . . . . . . . .TECHNOLOGIES HOME PRINT BOOKMARKS Tables Table 1. . . . . . . 19 Backer rod materials . . . . . 16 Factors affecting sealant conditions . . . 30 Production rates. . Table 15. . . . . 46 Troubleshooting procedures for plowing . . 53 xiii . . . . . . . . . . . 40 Material and shipping costs . . . . . . . . . . . . . . . . Table 9. . . . . Table 16. . Table 8. . costs. . . . . . . . . . . . . . . . . Table 4. 50 Troubleshooting procedures for resawing . . . . . . Table 17. . . . . . . Table 13. Table 5.
. ASTM D 5893 silicone sealant specifications . . . . . . . . . . . . . . . . . .TECHNOLOGIES HOME PRINT BOOKMARKS Table 19. . . 58 Troubleshooting procedures for backer rod installation . . . 85 Table B-3. . . . . . . . . . 80 Table A-2. Table 20. . . . . . . . . . . . . . Table 21. . . . . . . . . . . 69 Troubleshooting procedures for cold-applied sealant installation . . . . 81 Table B-1. . 56 Troubleshooting procedures for airblasting . . . Rubberized asphalt specifications . . . . . 74 Table A-1. . . . . . . . 84 Table B-2. . . . . . . Example labor costs . 63 Troubleshooting procedures for hot-applied sealant installation . Example cost-effectiveness calculations . . . . . . . . 86 Table B-4. . . . . . . . . . . . . . . . . Troubleshooting procedures for sandblasting . . . . . . . . . . . . . . . . . . Table 23. . . . Table 22. 87 xiv . . Example equipment costs . . . . . . . . . . . . . . . . . . . . . . . . . Example material and shipping costs . . . . . . . .
Guidelines for planning a resealing project and steps for installing joint seals and inspecting the process are presented..0 Introduction This manual has been prepared for use by maintenance engineers. This study investigated the performance in PCC joints of various hot. * Italicized words are defined in the glossary. maintenance contractors. and inspectors as an easy reference for resealing* transverse and longitudinal joints in portland cement concrete (PCC) pavements. maintenance field supervisors. crew persons. 1999). The resealing of concrete-asphalt shoulder joints and sealing cracks in PCC pavements are not addressed. 1991.1 Scope of Manual Included in this manual are descriptions of procedures and materials recommended for resealing joints in PCC pavements..and cold-applied sealants using several methods of installation. as well as from the field results of a 7-year study (Smith et al. 1 . 1. obtained through reviews of literature and of current practice. Evans et al. The information contained in this manual is based on the most recent research.TECHNOLOGIES HOME PRINT BOOKMARKS 1.
The first is determining the need for resealing. sample cost-effectiveness calculations. the next step is planning the operation. 2 . choosing preparation and installation procedures. The construction phase of joint resealing is described in chapter 4. Chapter 3 leads the maintenance planner through the steps for selecting sealant and accessory materials. and estimating material and labor requirements.TECHNOLOGIES HOME PRINT BOOKMARKS 1. Chapter 2 of this manual contains a general procedure that can be easily modified to meet the needs of any highway agency. Details of each step of the preparation and installation operations are listed. specifying equipment. safety precautions. along with troubleshooting procedures for each operation. Once the need for resealing is determined.2 Overview Several steps are required for successful resealing of joints in PCC pavements. and inspection checklists to help ensure good resealing practices and high-quality results. The appendixes provide material testing specifications.
1 Seal Condition Joint sealant system effectiveness is judged by the sealant's ability to resist embedment of incompressible materials and the sealant system's success in preventing entry of water and incompressible materials into the joint.TECHNOLOGIES HOME PRINT BOOKMARKS 2.0 Need for Joint Resealing Excessive delay in replacing a failing sealant system in concrete pavement joints can result in more rapid deterioration of the pavement. A more complete method for determining whether a pavement needs to be resealed is to calculate rating numbers based on the sealant and pavement condition. Figure 1 presents a worksheet that can be used to estimate these properties. How. and available funding. Other agencies base their decision on pavement type. pavement and sealant condition. and table 1 gives recommendations about the need to reseal based on these properties. However. the following steps should be completed and results recorded on the pavement survey form: 3 . The following sections assist in determining the necessary ratings and conditions. can those responsible for maintenance determine when is the best time to reseal joints in concrete pavements? Some States specify that joints be resealed when a specified amount of sealant material (25 to 50 percent) has failed. and climatic conditions. 2. To evaluate pavement seal condition. if sealant is replaced too early. allowing moisture or incompressible materials to progress past the sealant to the underlying layers. precious maintenance funds may not have been used in the most costeffective manner. traffic levels. then.
% slabs Pavement Rating Good Fair Poor Current Joint Design Sealant age.0 1-5 1-5 5-10 Stone intrusion >3. mm Low Med High Max.0 Seal Rating Good Fair Poor Corner breaks. joint depth. % Trucks Traffic Level b Avg. joint width. yrs Avg. mm Traffic Conditions ADT (vpd). L M H Average faulting. oC Climatic Region a WF DF WNF DNF Spalls >25 mm. mm Days < 0oC Avg low / high temp. Seal Condition Low Med High Water entering.5 1. % slabs Pumping. mm <1. joint spacing. % length Pavement Condition Low Med High <5 < 10 10-30 > 30 Expected Pavement Life.53. See table 3. % joints <1 <1 <5 >5 >5 >10 Environmental Conditions Avg annual precip. mm Avg. Concrete pavement/joint survey form. > 10 5-10 yrs.. sealant depth. m a b See table 2. 4 .TECHNOLOGIES HOME PRINT BOOKMARKS Figure 1.
Rating Good Good Good Fair Fair Fair Poor Poor Poor Good Good Good Fair Fair Fair Poor Poor Poor Traffic Rating Low Med High Low Med High Low Med High Low Med High Low Med High Low Med High Freeze Wet Possibly Yes Yes Yes Yes Yes Possibly Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Dry Possibly Possibly Yes Possibly Yes Yes Possibly Yes Yes Possibly Yes Yes Yes Yes Yes Yes Yes Yes Nonfreeze Wet Possibly Possibly Yes Possibly Yes Yes Possibly Yes Yes Possibly Yes Yes Yes Yes Yes Yes Yes Yes Dry Possibly Possibly Possibly Possibly Possibly Possibly Possibly Possibly Yes Possibly Possibly Yes Possibly Yes Yes Possibly Yes Yes Sealants rated in "Good" condition do not require replacement.TECHNOLOGIES HOME PRINT BOOKMARKS Table 1. Climatic Region Sealant Ratinga Fair Fair Fair Fair Fair Fair Fair Fair Fair Poor Poor Poor Poor Poor Poor Poor Poor Poor a Pvmt. Decision table for resealing PCC joints. 5 .
% L ' Lf L tot x 100 Eq. and dirt to enter the joint. spalls. depth. subdivide the site into sections having similar seal condition and evaluate 5 to 10 joints from each section. Full-depth spalls can be identified by gently inserting a dull knife into the spall and observing if the knife tip can pass below the sealant. The percentage of water resistance loss can be computed using equation 1. 2. Determine from the construction records the type and age of the sealant. 4. If large variations in condition are evident. recording the following items on the pavement survey form: ! Water Resistance— The percentage of overall joint length where water can bypass the sealant and enter the joint. and torn or missing sealant. Record the maximum spacing between joints.TECHNOLOGIES HOME PRINT BOOKMARKS 1. developed by the Iowa Department of Transportation (DOT). sand. and sealant thickness. Cut 50-mm samples of sealant from a few joints and measure the joint width. Choose 10 or more joints whose sealant condition is representative of the entire site. ! Stone Intrusion— The amount of stones. and debris embedded in the sealant. the design joint width. 1 6 . and sealant thickness. cohesive failure (figure 3). 3. Bond failure can be determined by pulling the sealant away from the joint edge and inspecting for adhesion failure. They reduce water resistance and allow moisture. Carefully inspect each of the chosen joints. Common joint seal distresses include loss of bonding to the concrete sidewall (figure 2). Another method for locating areas of bond failure is with the Iowa vacuum (IA-VAC) tester. sand.
7 . Sealant adhesion failure.TECHNOLOGIES HOME PRINT BOOKMARKS Figure 2. Full-depth cohesion failure. Figure 3.
m. 8 . or poor condition. determine the sealant rating by calculating the seal condition number (SCN). = The number of high-severity seal conditions. This number can be computed using the following equation: SCN ' 1(L) % 2 (M) % 3(H) where:SCN L M H Eq. = The number of medium-severity seal conditions. 2 = Seal condition number. Stone intrusion can be rated using the following criteria. and circle the correct seal rating on the pavement survey form. = The number of low-severity seal conditions recorded on the pavement survey form. = Much sand and debris stuck to and deeply embedded in the sealant or filling the joint. m. = Total length of joint sections allowing the entrance of water. fair. = Total joint section length evaluated. and the rating should be recorded on the pavement survey form: Low = Occasional stones or sand stuck to the top of the sealant (or material embedded on the surface of the sealant/channel interface).TECHNOLOGIES HOME PRINT BOOKMARKS where: %L Lf Ltot = Percent length allowing water to enter joint. Medium High Next. Use the SCN and the following rating to determine whether the existing joint seal is in good. = Sand or debris stuck to sealant and some debris deeply embedded in the sealant.
and corner breaks. ! Faulting.2 Pavement Condition Pavement condition is the next item to identify. cracks. ! D-cracking can result from excess moisture beneath a pavement. A pavement will provide several indicators that the joint seal is not performing adequately and is allowing too much water to reach the underlying layers. and that voids are forming beneath one side of the pavement as a result of continual traffic. or drop-off between adjacent slabs. from excess moisture. 2. in part. These indicators include the following: ! Surface staining or the accumulation of fine material on the surface close to joints or cracks indicates pumping of the base or subbase. can indicate that excess moisture is reaching a watersusceptible base or subgrade.TECHNOLOGIES HOME PRINT BOOKMARKS Seal Rating Good Fair Poor SCN 0-1 2-3 4-6 Results of a seal condition rating can also be used to monitor the performance of joint seals and to assist in follow-up rehabilitation planning. and it contributes to formation of voids beneath the pavement. This results. A pavement system can also manifest the effects of the entrance of stones and other incompressible materials into pavement joints by the following: 9 .
PCN ' 1 (L) % 2(M) % 3 (H) where:PCN L Eq. ! The percentage of slabs containing full-depth spalls extending greater than 25 mm from the face of the joint. as well as permanent increases in joint width causing closure of nearby expansion joints. use figure 1 and equation 3. These items should be based on field inspection and the maintenance schedule. record the following items in the pavement condition section of the concrete pavement/joint survey form (figure 1). 3 M H = Pavement condition number. = The number of high-severity pavement condition indicators. ! The percentage of joints visibly indicating pumping. ! The percentage of slabs containing corner breaks. To evaluate the condition of a pavement considered for resealing. = The number of low-severity pavement condition indicators from the pavement survey form. To determine a pavement condition number (PCN). 10 .TECHNOLOGIES HOME PRINT BOOKMARKS ! Compression-related spalling of the walls of joints that are filled with sand and stones. = The number of medium-severity pavement condition indicators. ! Blowups and shattering of slab edges. ! The estimated number of years before the pavement requires major rehabilitation. ! The average vertical faulting movement.
Dry climates also may require highly effective seals to prevent the intrusion of incompressible material into the joint. and structural damage. sealants are stretched the most as pavements shrink and joints widen. which can result in joint growth.15 2. In extremely cold temperatures. Wet climatic regions need highly effective seals (approaching 100 percent effectiveness) to prevent water damage to susceptible base and pavement structures. When evaluating the climatic conditions that a pavement will experience. Extremely hot temperatures can compress improperly placed sealant.3 Environmental Conditions The effects of extreme temperatures and precipitation on joint seal and pavement performance cannot be minimized. determine the following information and enter it in the environmental condition section of the concrete pavement/joint survey form: 11 . blowups. forcing it above the pavement surface where it may be pulled out by vehicle tires.TECHNOLOGIES HOME PRINT BOOKMARKS Use the PCN and the following ratings to determine the condition of the existing pavement and circle the correct pavement rating on the pavement survey form: Pavement Rating Good Fair Poor PCN 0-3 4-5 6 .
12 . North Carolina. 2. use the next higher traffic level rating. identify the climatic region in which the pavement is located. Circle the correct climatic region on the pavement survey form. using the information from figure 1 and table 2.4 Traffic Conditions To identify traffic conditions. This information is available from the National Climatic Data Center in Asheville. Climatic region parameters Climatic Region Wet-Freeze Wet-Nonfreeze Dry-Freeze Dry-Nonfreeze Mean annual days < 0oC > 100 < 100 > 100 < 100 Average annual precipitation > 635 mm > 635 mm < 635 mm < 635 mm ! The normal annual total precipitation for the location. ! The highest and lowest recorded temperatures. Then. If the percent trucks is greater than 10 percent or the expected growth rate is greater than 5 percent. or from local weather recording stations.TECHNOLOGIES HOME PRINT BOOKMARKS Table 2. Determine the traffic level rating from table 3. ! The mean number of days in a year with a minimum temperature of 0oC or below. obtain the average daily traffic (ADT) level and the percent truck traffic.
5 Determining the Need to Reseal After completing the pavement evaluation worksheet. it may be more critical to completely seal the transverse and longitudinal pavement joints. Agencies should use local experience for final determination of whether and how to reseal. 13 .000 5.000 2. Traffic Level Low Medium High ADT. If the recommendation is that sealing is "possibly" needed. the traffic rating. The basis for this table is engineering experience. vpd all lanes < 5. Choose the row with the combination of sealant. When an overlay or rehabilitation is scheduled within 3 to 5 years. pavement. use table 1 and the calculated SCN. If D-cracking is evident in the pavement surface. sealing could be delayed unless pavement or base damage would result. and traffic rating from the three left-hand columns that match the pavement being evaluated.000 to 35. then the case is borderline. Then find the intersection of that row with the appropriate climatic region to obtain the recommendation on the need for resealing. and the climatic region to evaluate the need for resealing. it can be adjusted to the needs and policies of individual State agencies.000 >35. PCN. and good judgment should be used in determining the need to reseal. Traffic-level rating.TECHNOLOGIES HOME PRINT BOOKMARKS Table 3. however.
it is important to determine the objective of the resealing project.and short-term objectives for resealing. ! Seal and maintain watertight joints for 3 to 5 years. 15 . Possible objectives include the following: ! Temporarily seal the pavement joints for 1 to 2 years until the pavement is overlaid or replaced.TECHNOLOGIES HOME PRINT BOOKMARKS 3.0 Planning and Design 3. Proper planning should take into account the following factors: ! The long. and efficient installation rates.1 Primary Considerations After determining the need to reseal the joints in a concrete pavement section. ! The level of strain placed on the sealant system as a result of the dimensions of the joint reservoir. ! Seal and maintain watertight joints for a period extending more than 5 years. ! The effectiveness of the equipment and installation methods chosen. ! The minimization of traffic disruption. increased worker safety. 3. ! The applicability and documented performance of the sealant materials chosen. it is important to plan the sealing operation to ensure that a proper resealing job is completed. ! The current sealant and pavement condition and the place of the resealing effort in an overall maintenance plan.2 Objective of Resealing When beginning.
it is more important to keep sand and dirt out of the joints to prevent spalling and blowups. A sealant should then be chosen that does not allow sand to penetrate the sealant surface.3 Accounting for Existing Conditions The condition of a pavement when it is resealed can greatly affect the performance of the seal. the objectives must match the requirements of the situation. Pavement in good condition and carries high level of traffic. 3. and poor load transfer can all reduce the effective life of resealed joints. In some situations. or allow stones to become embedded in the sealant.TECHNOLOGIES HOME PRINT BOOKMARKS Table 4. 16 . voids beneath the pavement. In hot climates. Objective Temporarily seal pavement. Major rehabilitation scheduled in 5 years. Each of these objectives may be correct for a different situation. faulting. when choosing sealant materials and installation methods. depending primarily on the pavement condition and the traffic level. only certain areas of sealant have failed and selective replacement is needed. some of these pavement distresses should be repaired before sealant is installed (Collins et al. a jet-fuel resistant (JFR) sealant material is required. 1986). or track on the surface. Pavement in fair condition. Maintain seal as long as possible. Condition Pavement to be overlaid in 1 to 2 years. some sealants flow down into the joint. Relationship between pavement condition and sealing objectives. Corner breaks.. Consequently. Maintain seal until rehabilitation. large spalls. In dry climates. Depending on existing conditions. In some pavements. as illustrated in table 4.
The condition of the existing joints and sealant can reveal much about the conditions under which it failed. Several of these indicators are listed in table 5. if needed. care should be taken to address and eliminate them for the resealing project.. 3. Undersealing the pavement where voids exist. the following repairs should be considered (Darter et al.TECHNOLOGIES HOME PRINT BOOKMARKS Specifically. Improving subdrainage or roadside drainage. 1987). Partial-depth repair of spalls that extend more than 25 mm from the face of the joint. prior to resealing. When these or other conditions are evident. Restoring load transfer at joints and cracks where poor load transfer exists. The condition of the sealant in longitudinal joints and transverse cracks should also be evaluated to determine if resealing is appropriate (Carpenter et al. Each of these repairs. Grinding the pavement surface to restore a smooth ride or to improve traction. Studies have shown that extensive pavement damage can occur due to the large amount of water entering a pavement system through open transverse cracks and longitudinal joints. 1985): ! ! ! ! ! ! Full-depth repair of corner breaks and deep spalls.. Selected sealants must have the following capabilities: 17 . should be completed before resealing begins.4 Selecting a Sealant Material Type Sealant materials are subjected to very harsh conditions.
However. Sealant pulled away from joint edges at random positions. There are a wide variety of sealant materials on the market. Table 6 contains a listing of sealant material types commonly used in resealing joints in PCC pavements. no one sealant can meet the demands of every resealing project. Large amount of joint movement. Applicable specifications are also listed. To help the designer in choosing a sealant material.. Maintain complete bond to concrete joint sidewalls at all temperatures.. Factors affecting sealant conditions. Poor sealant or placement methods. and excess moisture.TECHNOLOGIES HOME PRINT BOOKMARKS Table 5. the allowable extension and cost range are included. Sealant tracked on pavement. 18 . Sealant overheated. ! ! ! ! Withstand horizontal movement and vertical shear at all temperatures to which they are exposed. Observed Sealant Condition Sealant pulled away from edges along majority of the site. Joint may not have been cleaned properly. contaminated. Sealant selection should be based on the objectives of the resealing project. Possibly Indicates That. Resist penetration by stones and sand at all temperatures. or has too low a softening point. Withstand environmental effects such as weathering. extreme temperatures. The allowable extension is the manufacturerrecommended maximum in-place sealant extension. each with its own characteristics and costs.
Many agencies have full-scale testing programs to determine the performance of potential materials under local conditions.50 to $9.TECHNOLOGIES HOME PRINT BOOKMARKS Table 6. Commonly used lab specifications are shown in appendix A.00 $6. since the seals tend to twist or move up or down in the joint at locations where the joint edge is not vertical and completely smooth. AASHTO M 173. Design Sealant Material Applicable Specifications Extension. 19 . Thorough field and laboratory testing is recommended before any sealant is used on a large-scale project. AASHTO M 301 Modified ASTM D 3405 10 to 20% Cost Range.20 to $7.00 Rubberized Asphalt Low Modulus Rubberized Asphalt Polysulfide (1 & 2 Part) Polyurethane Silicone (non-sag) Silicone (self-leveling) a b 15 to 30% 30 to 50% $0.70 to $1.20 $6. Summary of sealant materials.75 $0. Compression seals are not typically used when the pavement joints are spalled. ASTM D 3405. $/L b $1.75 to $2.20 Not Available $5.50 to $9. Based on 1998 estimated costs.60 to $1. % a PVC Coal Tar ASTM D 3406 ASTM D 1190.50 Fed SS-S-200E Fed SS-S-200E ASTM D 5893 ASTM D 5893 10 to 20% 10 to 20% 30 to 50% 30 to 50% Consult manufacturers for specific design extensions.
The manufacturers'recommendations should be followed when selecting rod type. backer rod that absorbs water may shorten the life of the sealant material. non-shrinking.5 Selecting Backer Materials Backer rod is typically inserted in PCC joints prior to resealing to keep the sealant from sinking into the reservoir. Each type has specific properties and intended uses. Section 3. Backer tapes that require a more shallow joint have also been used. since sealant and backer rod must be compatible. Softer. Shrinking rod may allow sealant to flow past the rod before the sealant sets. 3. extruded foam rods have been developed to better seal joints with irregular edges. compressible. and non-absorptive. while others are intended only for cold-applied sealants. several backer rod types are designed to withstand the extreme temperatures of hot-applied sealants. It also keeps the sealant from bonding to the bottom of the reservoir and. Several currently available types of backer rod are described in table 7.TECHNOLOGIES HOME PRINT BOOKMARKS A life-cycle cost analysis (LCCA) should be performed to determine the material with the least average annual cost over the expected life of the pavement. it helps maintain the proper sealant thickness. For example. if properly selected and installed. non-reactive. The rod must be flexible. Finally.11 includes a worksheet to assist in conducting an LCCA. Backer rod that reacts with certain sealants may produce bubbles in or staining of the sealant. The more commonly used backer rod materials for 20 .
Backer rod is available in diameters ranging from 10 to 75 mm or more. The purpose of a primer is to bond to the concrete surface and provide a surface to which the new sealant can bond well. NS. 3. NG. a sufficient range of rod sizes should be on hand to obtain a tight seal in all joints. ECI. NS HR. Backer rod materials. primer may be recommended by the planner or the sealant manufacturer. The rod diameter should be at least 25 percent larger than the joint width. For cold-applied sealants. Primer may also be used when past experience 21 . NS NMA. ECI. NMA. Backer Material Type Extruded closedcell polyethylene Cross-linked extruded closedcell polyethylene Extruded polyolefin Applicable Standard ASTM D 5249 Type 3 ASTM D 5249 Type 1 ASTM D 5249 Type 3 Properties NMA.and cold-applied sealants Most coldapplied sealants CI = Chemically inert NG = Non-gassing ECI = Essentially chemically inert NMA = Non-moisture absorbing HR = Heat resistant NS = Non-staining IJ = Fills irregular joints well hot-applied sealants are cross-linked extruded foam rods.6 Selecting Primer Materials In areas where high humidity and moisture make it difficult to obtain a good bond between the sealant and the concrete. CI.TECHNOLOGIES HOME PRINT BOOKMARKS Table 7. IJ Compatibility Most coldapplied sealants Most hot. extruded closed-cell polyethylene foam or extruded polyolefin foam rod is typically used. Since joint widths may vary within a rehabilitation project.
In addition. 3. two major items must be determined: the shape factor and the expected joint movement. Difficulties in obtaining a good bond with soft aggregate can also be reduced by use of a primer. In designing the dimensions of a joint sealant and the sealant reservoir. If a joint is too narrow and temperature changes cause the joint to widen significantly. The sealant recess is designated as "R." Manufacturers' recommendations should be followed when choosing a shape factor. Silicone manufacturers recommend a minimum thickness of 6 mm and a maximum of 13 mm. Consult sealant manufacturers for primer type recommendations when the need for priming the joints exists. 22 . with most of the use occurring in wet or cold climates. in the same way that a thick rubber band cannot be stretched as far as a thin one before tearing. Figure 4 shows the dimensions of a typical sealant reservoir containing sealant material and backer rod. Primers are currently used in only a small percentage of major PCC resealing operations. 1983. the sealant may be stretched beyond its breaking point or pulled away from the concrete." and the joint channel depth is "D. ACI. Typical recommended shape factors are shown in table 8. if a thick sealant is stretched.7 Selecting Joint Reservoir Dimensions The width of a joint and the thickness of the sealant in that joint can significantly affect the performance of the seal (USAF.TECHNOLOGIES HOME PRINT BOOKMARKS indicates that it is difficult to obtain a good bond with the specified sealant. 1990). The shape factor is the ratio of the sealant width to the thickness (W:T). it may tear or not stick to the concrete.
Sealant Material Type Rubberized Asphalt Silicone PVC Coal Tar Polysulfide and Polyurethane Typical Shape Factor (W:T) 1:1 2:1 1:2 1:1 23 . Typical joint cross section.TECHNOLOGIES HOME PRINT BOOKMARKS W R T D Sealant Backer Rod Figure 4. Table 8. Typical recommended shape factors.
mm. Winit = Joint width at the time of sealant placement. a = Thermal coefficient of contraction for PCC (9. mm. C = Subbase/slab friction resistance adjustment factor (0.. 6 24 . Based on equation 4. 4 where: M = Joint opening movement caused by temperature change of PCC. M ' CL aT Eq. mm.80 for granular subbase). percent. the percent elongation that the new sealant must allow is determined by the following equation: %Emax ' 100 where: Mmax Winit Eq. Some engineers prefer to determine Mmax using the safer assumption that a joint between two slabs may be called upon to take the total movement of both slabs. mm. Mmax = Joint opening movement caused by change of PCC temperature.0 to 10. In this assumption: Mmax ' 2 M Eq. oC. 0. 5 %Emax = Estimated elongation. 1992). T = Temperature range (temperature at placement minus lowest mean monthly temperature).TECHNOLOGIES HOME PRINT BOOKMARKS The maximum joint opening movement for rehabilitated joint seals can be estimated using equation 4 (Bodocsi et al.65 for stabilized subbase.8 x 10-6/oC). L = Joint spacing.
Some manufacturers recommend that an extra 6 mm be added when resealing joints to prevent water and material beneath the sealant from pushing the sealant up and out of the joint.6 4. The joint width. Extra depth is also needed to account for variability in the sawing operation. base is stabilized. This table is based on limiting the sealant stress to less than 20 percent.3 a b c Minimum Joint Width. mm a Nonfreeze Region b 6 6 to 10 10 to 13 13 to 19 Freeze Region c 10 10 to 13 13 to 19 19 to 29 Installation temperature is 27oC. 1983). the compressed backer rod thickness. typically 20 percent. should be wide enough to keep the sealant from being stretched in cold weather more than the design amount.6 7.7 to 12. 1986. there is a tradeoff in the Mmax approach between reduced sealant fatigue and reduced allowable future joint widening.7 to 7.2 12. Lowest freeze region mean monthly temperature is -26oC. D.3 to 18. Suggested sealant thicknesses and minimum joint widths for various joint spacings are listed in table 9 as a check for more detailed joint design. However. As a result. %Emax < 20%. should be the sum of the selected sealant thickness. Typical joint design dimensions. joints should not typically be wider than 19 mm (Collins et al.. The joint reservoir sawcut depth. W.TECHNOLOGIES HOME PRINT BOOKMARKS Table 9. Maximum Joint Spacing. m < 4. and the depth that the sealant surface is to be recessed. Minimum nonfreeze region temperature is -7oC. 25 . USAF.
8 Selecting Preparation and Installation Procedures The type of joint cleaning procedures and the final cleanliness of the concrete joint walls prior to sealant installation can significantly affect the performance of sealant materials. Each option. The selection of which combination of preparation and installation procedures to use should be based on the condition and requirements of each individual resealing project. if followed completely. should result in clean joint surfaces and increase the chances for good performance. ! Joint widths or depths do not meet the minimum design requirements. the better a sealant will adhere. This option can be used only when it can be demonstrated that sufficient joint surface cleanliness can be achieved without water washing. As a rule. Option 3 adds a plowing operation to the option 2 procedures. Four combinations are shown in table 10. Therefore. the cleaner and drier the joint surfaces are. ! The existing sealant is hardened and will not melt and "gum-up" the saw blades. Option 1 should be considered when: ! The resealing project carries a high volume of traffic. preparation and installation procedures should be chosen as carefully as sealant materials. and the more effective it will be. Option 2 differs from option 1 only by the elimination of water washing. It should be used when: 26 . ! A high-quality sealant is being used.TECHNOLOGIES HOME PRINT BOOKMARKS 3.
leaving fresh. 1991. ! The joint dimensions are not adequate. It can significantly reduce the preparation time and.. Evans et al. 1993. ! The plowing equipment removes more than 95 percent of the sealant from the joint faces.TECHNOLOGIES HOME PRINT BOOKMARKS Table 10. If compression seals are being replaced with formed-in-place sealant. Several methods of sealant installation have also been used with varying results (Smith et al. it allows immediate cleaning and resealing.. 1993. since it is a dry operation. unspalled concrete.. 1986). Option 1 2 3 4 T T Plow Saw T T T Water Initial Sand Final Backer Recessed Wash Airblast Blast Airblast Rod Sealant T T T T T T T T T T T T T T T T T T T T ! A saw is melting the existing sealant and cannot remove the sealant efficiently by itself. Lynch et al.. These include: 27 . Joint preparation/installation procedures. Evans et al. Option 4 replaces the sawing operation with an effective plowing operation. It may only be used if: ! The joint dimensions are adequate. ! The sandblaster is able to efficiently remove any remaining sealant. 1999). sawing is not required when sandblasting can completely remove the old lubricant from the joint walls (Collins.
! Recessing the sealant below the pavement surface. ! Keeping the sealant surface level with the pavement surface. ! Overbanding sealant onto the pavement surface. Overbanded seals tend to oxidize at a slower rate than recessed asphalt-based sealants because of the massaging action of traffic tires. As a result, adhesion failures may occur more quickly in recessed sealants. A 7-year study of joint seals in five States indicates that overbanded ASTM D 3405 seals have statistically outperformed recessed seals even when installed in transverse joints on heavily trafficked roadways (Evans et al., 1999). In longitudinal lane-shoulder joints, overbanding may provide better performance than recessed seals. Therefore, in reduced traffic areas, such as low-volume roads or lane-shoulder joints, overbanded sealants may be the most effective choice. There are two drawbacks of overbanding on PCC pavements. First, overbanded sealant material is typically worn away by traffic within 1 to 3 years. After it is worn, traffic tires tend to pull the sealant from the joint edge, leading to adhesion failure. Second, the scraping action of ice blades on highways in cold regions tends to pull up overbanded seals from the pavement surface. Silicone sealants should never be overbanded or flush with the pavement surface. Manufacturers recommend a minimum of 7 to 10 mm recess below the pavement surface for all silicone sealants to avoid the premature adhesion failure noted in the Long-Term Pavement Performance (LTPP) Specific Pavement Studies (SPS)-4 test sections in four States (Smith et al., 1999).
3.9 Selecting Equipment
Selection of equipment for the resealing process should be based on its ability to complete the task. This ability should be proven prior to beginning the resealing operation by constructing a test resealing section. A contractor or highway maintenance crew should be allowed to choose the equipment that will effectively clean and reseal concrete joints in the most efficient manner. However, several items have been shown to be important to successful use of each piece of equipment. These requirements are listed in table 11. 3.9.1 Joint Plows A joint plow used only to remove sealant prior to sawing must remove enough sealant to keep the saw blades from gumming up. A shop-made, rear-mounted plow for this purpose is shown in figure 5. If the plow is used without resawing, it must be able to efficiently remove at least 95 percent of the old sealant from the joint walls and not spall the joint sidewalls. Plowing has also been successfully accomplished by attaching a hydraulically controlled carbide-tipped blade to the underbody of a small (13.4 to 17.9 kW) tractor, as shown in figure 6. Multiple blade sizes should be on hand to keep the blades from binding in narrow joints. Plow blades generally have straight sides, but they may be tapered. Tapered blades tend to spall the joint edges, especially at intersections with other joints, at pavement edges, and where the joint width changes quickly. Straight-sided blades must be forced against the side of the joints to more thoroughly clean them, but the risk of spalling is greatly reduced when the blade width is narrower than the joint width.
Table 11. Joint resealing equipment requirements.
Equipment Joint Plow Requirements Non-tapered, carbide-tipped blades. Sufficient blade sizes. Ability to control blade height. Ability to force blade against sidewall. Self-propelled, water-cooled saw > 26 kW. Diamond saw blades designed to cut hardened PCC to uniform width. Controllable, does not pull to one side. Acceptable air compressor. Recommend Venturi tungsten nozzles. Functional oil and water removal filter on compressor. Min 620 kPa at 0.07 m3/s. > 19-mm ID hose. Nozzle with shut-off valve. Face shield, ear protectors. Maintains proper recess, + 3 mm. Does not damage backer rod. Mechanical agitator (recommend full-sweep agitator). Separate automatic temperature controls for oil and melting chambers. Sealant heating range to 260oC. Sealant recirculation system. Minimum flow rate 0.025 L/s. Recommend hose lined with Teflon, all seals and packing made with Teflon.
Concrete Saw (includes saw, hose, and water truck)
Sandblast Equipment (including sandblast unit, air compressor, hoses, nozzles, and safety equipment) Airblast Equipment (includes air compressor, hose, wand, and safety equipment)
Backer Rod Installation Tools Hot-Applied Sealant Installation Equipment (includes portable melter–applicator, hose, wand, and safety equipment)
Silicone Sealant Installation Equipment (includes pump, compressor, hose, and wand)
Figure 6.TECHNOLOGIES HOME PRINT BOOKMARKS Figure 5. 31 . Undercarriage-mounted joint plow. Rear-mounted joint plow.
uniform width in one pass (Darter et al. full-width blades are also used to resaw joints for resealing. Selfpropelled.9. Figure 7.TECHNOLOGIES HOME PRINT BOOKMARKS 3.. 1985). water-cooled power saws with diamond blades. blades are ganged side-by-side on the blade arbor with a solid metal spacer to allow the saw to reface the joint to a proper. and longer blade life. more uniform sawing widths. The spacer diameter must be sized to prevent sealant from building up between the blades. are typically used for joint refacing. Ganged blades can be exchanged on the arbor to provide more even wear.2 Concrete Saws Saws used for refacing the joint should remove the minimum amount of concrete to achieve the design width and produce freshly sawn. clean joints of uniform width and depth. 32 . Concrete joint saw. Single. In many cases. as shown in figure 7.
The air supply must be clean. lengths. and any old sealant from the joint faces. A sandblast chamber that allows continuous sand loading increases production rates. Attaching an adjustable guide to the nozzle to keep it 25 to 50 mm from the pavement promotes consistent results and reduces operator fatigue.to 4-h projects.to 6-mm-diameter Venturi nozzle has been used successfully for sandblasting joints. since smaller blades are less expensive and make the saw easier to maneuver. 3. dry. and free from oil.07 m3/s. and the body of these blades must be thick enough to resist warping. an abrasive blasting unit. This may require the installation of an oil and moisture filter on the air compressor. dirt. For worker protection and to conform to State and Occupational Safety and Health Administration (OSHA) requirements. and shapes. all necessary safety equipment must be present and in good working condition.TECHNOLOGIES HOME PRINT BOOKMARKS Blades should be no larger than necessary to achieve the required depth. as shown in figure 8. A 5. To efficiently accomplish this for a medium to large resealing project. should maintain a minimum nozzle pressure of 620 kPa at 0.9.3 Abrasive Blasting Equipment Sandblasting equipment must be able to completely remove dried sawing slurry. Tungsten carbide and ceramic nozzles are available in several diameters. Blades specifically designed for resawing hardened concrete should be used. Tungsten carbide nozzles should be used for larger projects. and ceramic nozzles are more useful for 3. This equipment may include: 33 .
3.9. pressure. Abrasive blasting equipment.TECHNOLOGIES HOME PRINT BOOKMARKS Figure 8. is used for final cleaning. An air supply purifier.4 Airblasting Equipment An air compressor. Protective clothing for the operator. Portable protective barriers between the sandblaster and adjacent traffic. An air-fed protective helmet. as shown in figure 9. and 34 . and must produce sufficient air quality. ! ! ! ! ! A remote shut-off valve.
the inside of the hose for a lubricating air compressor is coated with oil. this must be disconnected and an effective oil and moisture trap must be installed. and contain no oil. ! A compressor with a minimum of 0. volume to thoroughly clean the joints. Attaching a balanced wand with a shut-off control increases safety and improves worker comfort. 35 . Airblasting operation.TECHNOLOGIES HOME PRINT BOOKMARKS Figure 9. Many modern compressors automatically insert oil into the air lines to lubricate air-powered tools. This requires the following: ! The air supply must be clean. dry. In most cases.07 m3/s at the nozzle and 690 kPa must be used. This oil must be removed or the hose must be replaced to keep oil from reaching the joints. For joint cleaning. Proper eye and ear protection should also be used.
stretching. The temperature and movement rate must be closely controllable to reduce the possibility of overheating the pavement. used to dry slightly damp joints must supply heated air at about 1. 3. or heat lance. as shown in figure 10. since overheating can produce chalking and temperature/steam-induced stress fractures. due to the heat and noise produced by this equipment. ear. and balancing straps.5 Hot Airblasting Equipment A hot compressed air (HCA) lance. or damaging the rod. Hand-operated backer rod installation tool. Figure 10.6 Backer Rod Installation Tools A backer rod installation tool must be able to push the backer rod into a joint to the specified depth without tearing. and body protection devices must be used. Eye. wheels.TECHNOLOGIES HOME PRINT BOOKMARKS 3.9.9. Many sealant contractors make their own installation tools. Several heat lance options are available. 36 .100oC with a supply velocity of more than 300 m/s. including push-button ignition.
! Allow the operator to maintain exact sealant temperatures in the range of 160 to 250oC.TECHNOLOGIES HOME PRINT BOOKMARKS However. adjustable tool is commercially available. ! Be large and powerful enough to heat a sufficient amount of sealant so that installation is not delayed.9. a lightweight. Automated backer rod installation tool.325 L. self-guiding unit like the one shown in figure 11. 37 . Figure 11. 3. Many companies manufacture mobile equipment that will melt and pump sealant into pavement joints.7 Hot-Applied Sealant Installation Equipment The equipment used for installing sealant materials that must be heated should be able to: ! Effectively raise the temperature of the sealant without overheating portions of the sealant. The sealant capacity of most melter–applicators ranges from 190 to 1. as is an automated.
1983). 38 . ! Maintain a feed rate of at least 0.9. and hoses and wands that are insulated or heated (Bugler. ! A mechanical agitator. diesel heating fuel. 3.8 Silicone Sealant Applicators Silicone pumps and applicators should provide sealant to the joint at a rate that does not slow the operator.TECHNOLOGIES HOME PRINT BOOKMARKS Characteristics of the melter–applicator equipment should include the following: ! A double-walled heating chamber with heating oil between the walls as the heat transfer medium. ! Have a nozzle designed to fill the joint from the bottom. The applicator equipment should: ! Not introduce bubbles into the sealant. Options that may be helpful include electronic ignition. ! Accurate thermostats to monitor both the sealant and the heating oil temperatures (these thermostats should control the operation of the burners). Applicators that have Teflon-lined hoses and Teflon seals are less likely to allow the sealant to cure in the pump or hose than those that use neoprene seals and standard hoses. ! Not allow air to reach the sealant before it enters the joint. ! A reversible pump that can feed sealant to the applicator wand or recirculate the sealant into the melter vat. ! Nozzle attachments with outside diameters that are small enough to allow it to be pulled through the narrowest joint without binding and large enough to maintain a good installation rate. to prevent premature curing. wand nozzles that maintain the sealant at a certain depth.025 L/s.
a hand-held infrared thermometer can provide quality control checks of melter–applicator and nozzle sealant temperature and the temperature of the pavement joints.10 Estimating Material. 3. A long rod with properly sized flexible plastic tubing attached to the end is useful for forming the surface of non-self-leveling silicone sealants. They are not generally recommended.9 Other Equipment Under some conditions. low-modulus rubberized asphalt. This table contains estimated material amounts and preparation and installation rates. The plowing rate can be influenced by the number of passes required and the difficulty in aligning the blade with the joint. and the second is a hot-applied. labor. 1983). Costs and rates for two scenarios are shown. and equipment requirements. Labor. for hot-applied sealant installation. The first is a self-leveling silicone with a shape factor of 2:1. a self-propelled vacuum sweeper or portable air blower may be useful for removing sand and dust from the pavement surface prior to backer rod installation. Rotary wire brushes have been used for joint wall cleaning with very limited success. and Equipment Requirements The information in table 12 is provided to help with estimating the material. Also. 39 . due to their tendency to scrape the cement (which produces dust) and to smear old joint sealant over the dust (USAF.TECHNOLOGIES HOME PRINT BOOKMARKS 3.9.
5 to 4 h 1. Production rates for initial and final airblasting can vary with the capacity and pressure provided by the air compressor. and the size of the aggregate in the concrete. The rate of primer installation varies greatly with the application method. The speed of backer rod installation is dependent upon the consistency of the joint width. Where old sealant remains on the joint walls. the hardness of the concrete. If joint widths vary significantly. costs.5 to 4 h 1.5 h Sealant installation rate Based on 13-mm joint width. A 270-kg capacity sandblast unit with a 6-mm nozzle and 25-mm inside diameter sandblast hose can use about 270 kg of abrasive per hour. and abrasive type used.5 h 1.5 h 2 1 2 2 2 2 2 to 3 h 3. No. Large amounts of debris in the joint or on the pavement surface will slow the airblasting operation. nozzle.TECHNOLOGIES HOME PRINT BOOKMARKS Table 12.5 to 4 h 1 to 3 h 1. the blade speed.5 to 2. Production rates.5 to 7. Large-volume spray units result in much greater production rates than brushing the sealant on by hand. of Workers Average sealant amount a Average plowing rate Average sawing rate Average sandblast rate Final airblast rate Backer-rod installation rate a Amounts/Rates (per 300 m) Silicone 26 to 38 L Hot-Applied 49 to 57 L 2 to 3 h 3.5 h 1. backer rods of different diameters must be used to fill the joints. 40 . the cutting depth and pressure. and amounts. the rate of sandblasting will decrease. the type and width of blade. Sawing rates are influenced by the power of the saw. The rate of sandblasting is a function of the equipment.5 to 4 h 1 to 3 h 1.5 to 2.5 to 7.
since time must be allowed for the concrete to dry.TECHNOLOGIES HOME PRINT BOOKMARKS This. blasting abrasive. Estimate the effective service life of each resealing option. Estimate the labor needs and costs. Coverage rates for sealant can be 41 . backer rod. High rainfall frequency can significantly reduce the rate of sealant installation. The rate of sealant application is controlled by the skill of the operator. primer. 2. the dimensions of the sealant reservoir. and the production rate of the melter–applicator (hot-applied) or pump (silicone). requires the installer to carry backer rods of various sizes. Example calculations are included in appendix B. Determine the equipment requirements and costs. 4. and other required materials can be obtained from local suppliers or manufacturers. the distance between joints. 3. in turn.11. 3. 3. Determine the amounts and costs of the materials needed.11 Determining Cost-Effectiveness Steps for determining the cost-effectiveness of methods and materials for resealing joints in PCC pavements include the following: 1.1 Material and Shipping Costs Material and shipping costs can be determined using table 13. and to sometimes install very short lengths of rod. Material costs for sealant. 5. Calculate the average annual cost for each method under consideration.
CR ' 0. Material Cost. T = Thickness of sealant. mm (see figure 4). m/unit Length Required. non-tooled surface: ST = 1. 42 . By multiplying the material cost.TECHNOLOGIES HOME PRINT BOOKMARKS Table 13.001 WF ST W T Eq. the total cost for each material and the overall material cost can be estimated. and the length of the joint to be resealed. the coverage rate. kg Primer. L Total Material Cost: b c axbxc Coverage Rate. mm (see figure 4). ST = Surface type constant (tooled surface: ST = 1. W = Joint width. linear m Total Cost.0).2 for 20 percent waste).1. unit a Sealant. L/m. Material and shipping costs. $/unit Material. linear m Blasting Sand. WF = Waste factor (WF = 1. $ estimated by using equation 7 or by consulting manufacturers' literature. L Backer Rod. 7 where: CR = Sealant coverage rate.
Experienced traffic engineers or agency guidelines should be consulted in defining the cost of user delays. and the expected time necessary to complete each operation. the number of workers required for each operation. In addition to wage rates.2 Labor Costs Labor costs can be determined using table 14. 3. there is a cost of delay to roadway users during the time that joints are cleaned and resealed.11. Using the wages for each worker. It should be included in cost-effectiveness calculations if the options being evaluated require significantly different amounts of lane closure.TECHNOLOGIES HOME PRINT BOOKMARKS 3. although the rates shown in table 12 may be used to obtain rough estimates.11. the cost of resealing equipment can be estimated.3 Equipment Costs The cost of equipment will be affected by the availability of adequate equipment and the need for equipment rental. The production rates and amounts in table 12 should be helpful in determining labor requirements. Production rates should be based on local experience. 43 . The amount of time that each piece of equipment is needed also greatly influences equipment costs.4 User Delay Costs Although difficult to determine. By completing table 15 and multiplying the daily equipment costs by the number of pieces of equipment required and the number of days the equipment is needed. labor costs are greatly influenced by crew productivity and the need for night work or extra traffic control. the total labor costs can be estimated.11. 3.
Installation Equip. Other Trucks Total Equipment Cost: Number of Units h Number of Days i Total Cost. Labor costs.TECHNOLOGIES HOME PRINT BOOKMARKS Table 14. Equipment costs. $/day g Traffic Control Joint Plow Concrete Saw Air Compressor Sandblast Equip. $ gxhxi Equipment 44 . $ dxexf Crew Labor Supervisor Traffic Control Plowing Sawing Initial Airblast Sandblast Final Airblast Backer Rod Sealant Installation Total Labor Cost: Table 15. Wages. $/day d Number in Crew e Days Required f Total Cost. Daily Cost.
The expected rate of inflation and the estimated lifetime of each material-placement method option are required inputs for the worksheet.5 Cost-Effectiveness Comparisons After the material. equipment. and user costs have been determined. the worksheet in table 16 can be used to determine the annual cost of each resealing option. By comparing the average annual cost of various materials and repair procedures. the most cost-effective resealing option can be determined.TECHNOLOGIES HOME PRINT BOOKMARKS 3.11. labor. 45 .
05) __________ $ __________ __________ __________ (B) (C) (D) (E) Average Annual Cost ' C E 1% E D 1 %E D &1 Eq. 8 Average Annual Cost ($/lane-km) $ 46 . 0.TECHNOLOGIES HOME PRINT BOOKMARKS Table 16. Total Material Cost [table 13] Total Labor Cost [table 14] Total Equipment Cost [table 15] Total User Delay Cost [table 16] $ __________ $ __________ $ __________ $ __________ =========== Total Resealing Cost $ __________ (A) Project Length (lane-km) Average Cost ($/lane-km) Estimated Lifetime of Seal. Cost effectiveness worksheet. years Interest Rate (typ.
since preparing clean joints and correctly installing the sealant material in an effective manner will largely determine the overall performance of the sealant system design. arrow boards. 47 . This chapter presents the objectives and steps required for cleaning and resealing joints in concrete pavements. it is critical that adequate traffic control be in place to provide a safe working environment for the installation crew and a safe travel lane for vehicles. joints can be prepared in the chosen manner and the sealant can be installed. Besides normal signs.1 Traffic Control Whenever a joint resealing operation is performed. cones. flaggers may be required to accompany the sawing and plowing operations if the plow or saw is allowed to extend into the lane carrying traffic. 4. operational worker protection devices must be used. 4.2 Safety Precautions The equipment and materials used in a joint resealing operation can present safety hazards to workers if appropriate precautions are not taken. Troubleshooting procedures for solving the problems potentially encountered in each operation are also included.0 Construction Once the design and planning stages are completed. It should also cause the least amount of disturbance possible to the flow of traffic. All guards must be in place. This construction stage is just as critical as the design stage. and attenuators.TECHNOLOGIES HOME PRINT BOOKMARKS 4. and appropriate clothing should be worn.
Good joint preparation is essential to good sealant performance. A more detailed description of safety precautions required for each step of the sealing operation is included in appendix C.3.TECHNOLOGIES HOME PRINT BOOKMARKS Material Safety Data Sheets (MSDS' should be obtained for s) each sealant material to be installed. dry. 4. 4. and properly dimensioned joints that are free from sawing dust. Preformed compression seals should be removed by hand or by pulling out longer sections with a tractor. and proper care should be taken to protect workers from any potentially harmful materials. the sealant will pull away from the joint walls prematurely. if the joint faces are not clean and dry.3 Preparing the Joint Objective: To provide clean. 48 . long-term performance. Successful steps for preparing joints for sealant installation include removing old sealant. airblasting. or any other contamination. and to which sealant material can adequately bond. abrasive blasting. Plowing involves pulling a thin blade through a joint to remove old sealant and backer material from the reservoir and to clean sealant from the sides of the joint. old sealant. and installing primer. No matter what the sealant material quality is. refacing joint sidewalls. Appropriate sealants placed in joints that are clean and dry should provide effective. Care must be taken with this operation to ensure that oils from the original oil-based sealant that have penetrated the joint edge are sufficiently removed. Hydroblasting has been used successfully for joint preparation.1 Removing the Old Sealant Plows can be used to remove old sealant from concrete joints prior to or in place of sawing.
! Effective traffic control and equipment guards to protect workers from flying debris and moving traffic. If sawing will not follow the plowing operation.TECHNOLOGIES HOME PRINT BOOKMARKS To effectively remove sealant prior to sawing. 49 .1. ! All sealant remaining on joint sidewalls must be easily removable by sandblasting. carbide-tipped plow blade for partial sealant removal (shown in figure 12). Successful use of a joint plow typically requires the following equipment and procedures: ! A rear. ! Multiple passes of a blade that is narrower than the joint. ! Joint walls must not be spalled by the plow. steel plow blades of various widths. Descriptions of joint plows are given in section 3. the following additional results must be achieved: ! At least 95 percent of old sealant must be removed from the joint sidewalls. cleaning each channel face individually. or an undercarriage-mounted carbide blade with hydraulic controls for complete sealant removal. Several common plowing problems and possible solutions are listed in table 17. Operators must use special care or an alternate procedure if difficulties with spalling or improper cleaning are encountered. ! Carbide-tipped.or front-mounted. the plowing operation must achieve the following results: ! Sufficient sealant and debris must be removed so that saw blades are not "gummed-up" during sawing. and a few have functioned successfully. Several types of plows have been used.9. ! Sufficient tractor weight to maintain blade depth and remove the old sealant.
Problems Encountered Plow is spalling joint edges. Use rear-/front-mounted blades. Redirect traffic. Use an assistant. or a vertical-spindle router.or front-mounted blades. Guardrail or curb keeps plow from reaching the entire joint. Table 17. Use hand tools or a vertical-spindle router.TECHNOLOGIES HOME PRINT BOOKMARKS Figure 12. Undercarriage-mounted plow places tractor in traffic. Use undercarriage-mounted plow. Trouble lining up plow with joint. hand tools. Use additional care in plowing. Use rear. Reverse plowing direction. Troubleshooting procedures for plowing. Use hand tools or a vertical-spindle router. Original sawcuts are offset. 50 . Possible Solutions Use an untapered plow bit or a narrower blade. Increase pressure on the joint sidewall. Plow not completely removing sealant. Joint plowing operation.
shown in figure 13. blowing away. ! Vacuuming.9. ! No spalls resulting from resawing. Some materials may require hazardous or specialized waste disposal methods. the remainder of the preparation tasks are greatly simplified. or picking up debris from the plowing operation. If the resawing operation is properly completed. The following concurrent work is recommended with the plowing operation: ! Blowing sealant and debris from the plowed joints. care should be taken to ensure accurate and complete sawing. Recommendations for watercooled saws and blades are discussed in section 3.3. fresh concrete to which new sealant can adhere. The following results of sawing must be achieved for the entire project: ! Uniform width and depth of joint in compliance with the design dimensions.2 Refacing the Joint Sidewalls Sawing. 4. joints in concrete pavements. and if 51 . is done either to increase the joint width and depth to the design requirements. ! Removing the old sealant and properly disposing of it. Therefore.TECHNOLOGIES HOME PRINT BOOKMARKS Removing old joint material and other debris should be a continual process during joint preparation.2. or refacing. ! Sealant completely removed and concrete freshly exposed on both sides of each joint. or to expose clean.
If this slurry dries on the joint walls. poor results are noticed. they should be corrected promptly. Consult saw manufacturers for solutions to other problems. Therefore. if it is not removed. Several common problems encountered in resawing are noted in table 18. it is very difficult to remove. Joint resawing operation. the sealant and slurry must be removed immediately after sawing by one of the following methods: 52 .TECHNOLOGIES HOME PRINT BOOKMARKS Figure 13. it will keep new sealant from bonding to the concrete. along with recommended solutions. Wet-sawing leaves behind old sealant and a slurry of water and concrete dust in the joint.
Switch the inside and outside blades. ! Flush the joints with high-pressure water until all sawing waste is removed.TECHNOLOGIES HOME PRINT BOOKMARKS Table 18. Increase the cutting rate. simultaneously blowing the slurry out with high-pressure air until all sawing waste is removed (Darter et al. 4. 1985).3 Abrasive Blasting the Joint Sidewalls An abrasive blasting apparatus is used to direct a mixture of clean. Check rear-wheel alignment. Saw cut does not begin in the center of the joint. One side of ganged blades worn. Problems Encountered Blade pulling to one side. Sealant "gumming-up" blade. ! Clean the joints with high-pressure air until all sawing waste is removed. ! Flush the joints with low-pressure water. Poor control— use a more skilled operator. Adjust the water feed.3. Use a more powerful saw. Provide an assistant to the operator. dry air and abrasive material onto the walls of concrete 53 . Troubleshooting procedures for resawing.. Possible Solutions Change the rate of sawing. Narrow blade— use wider blades. Use a more appropriate blade. Sawing is slow. Remove (plow) sealant before sawing. Blade not cleaning both sides. Have the saw operator take more care. The first and second methods are more effective than the third at removing concrete dust slurry.
To achieve these results. Remove any old sealant with repeat passes or with a knife and repeat passes. Protect traffic in nearby lanes from sand and dust. A long handle attached to the hose and extending slightly past the nozzle will allow this to be done from an upright position. 2. ! Joint walls must be completely clean and dry.TECHNOLOGIES HOME PRINT BOOKMARKS joints. 6.9. 3. The following procedures can provide successful abrasive blastcleaning results: 1. using airblasting or vacuuming equipment. lubricant adhesive. as described in section 3. old sealant. as well as the roughening of the concrete surface in order to create a better bonding surface. the abrasive blasting operation must produce the following effects: ! Joint walls to which sealant must bond must be free from all sawing dust. Remove sand and dust from the joint and nearby pavement to prevent recontamination. or any other form of contamination. 5. 54 . as shown in figure 14. Hold the sandblast nozzle no more than 50 mm from the pavement surface. 4.3. and safety procedures. discoloration or stain. by using a portable shield and low-dust abrasive. Make one complete pass for each joint wall at an angle from the pavement that directs the blast onto the surface to which sealant must bond. and other foreign material from the concrete joint surfaces. Use approved sandblast units. as necessary. and have newly exposed concrete. Results of abrasive blasting include the removal of sawing dust. safety equipment. old sealant.
If this is not done. Abrasive blasting operation. Self-propelled vacuums and portable blowers can be used for debris removal. The sand and dust must be removed from the joints and pavement surfaces before sealing can begin. reducing sealant performance. 55 . sand and dust can be blown back into the joints. Problems that are encountered in sandblasting must be solved quickly. Several common sandblasting problems and possible solutions are listed in table 19.TECHNOLOGIES HOME PRINT BOOKMARKS Figure 14.
Improve the accuracy of sawing. 56 . Use a nozzle guide attachment. Use a different blaster or abrasive or larger hoses. Possible Solutions Ensure that sandblaster is functioning. and immediately before sealant installation.4 Airblasting the Joint Reservoir After the joints have been sandblasted. 4. Sandblast progress too slow. Use a guide and handle for upright sandblasting. Use a different blaster or abrasive or a larger hose. dust. the dust. The following results of airblasting are desired over the entire project: ! Sand. Ensure that sandblaster is functioning. dirt.3. Problems Encountered Sandblast not removing sealant. Keep the nozzle height and alignment consistent. and sand must be blown from the joints and pavement surface using a compressed air stream. Sandblast quality not consistent.TECHNOLOGIES HOME PRINT BOOKMARKS Table 19. Blast joint edges separately. Ensure that sandblaster is functioning. Oil or moisture in sandblast stream. and dirt must be completely removed from the joint reservoir. Use dry abrasive. Use alternating operators. Troubleshooting procedures for sandblasting. Install a functional oil/moisture filter. Cut old sealant away and reblast. Operator fatigue. Use another compressor that doesn't add oil or moisture.
dust. rod placement. Figure 15. and safety procedures. and sealant installation operations must occur on the same day. Use approved air compressors.TECHNOLOGIES HOME PRINT BOOKMARKS ! Any sand. In general. 3. as shown in figure 15. If rain or dew recontaminate the joints. 2. Hold the nozzle no more than 50 mm from the pavement surface.9. The airblasting. joints should be airblasted immediately prior to backer rod installation. safety equipment. Blow debris in front of the nozzle. as described in section 3. 57 . and dirt that may recontaminate the joints must be removed from the surrounding pavement surface. Successful airblasting methods for accomplishing the above results are as follows: 1. Do not walk backwards. they must be sandblasted and airblasted again after drying. Airblasting operation.4.
Reduce the diameter of the nozzle opening.TECHNOLOGIES HOME PRINT BOOKMARKS 4. Clean or replace the hose. n. Problems Encountered Oil in airstream. Possible Solutions Ensure oil/moisture filter is functional. The most common problems encountered in airblasting are related to contamination of the air stream or lack of air volume and pressure.). Make slower or repeated passes until the joint reservoir is completely clean. dirt. a heat lance may be used to dry the joints prior to installing backer rod (Mildenhall. Elevate and fan the nozzle across the pavement on the last pass to remove debris from the joint area to a place where it cannot recontaminate the joints. The extreme temperatures that a heat lance can produce (820 to 1. 5.650oC) can severely spall concrete pavement that is exposed to the heat for more than a very short length of time. Ensure that oil/moisture filter is functional. Use a larger diameter hose. Moisture in airstream. Methods for addressing these problems are described in table 20. but capillary action in the concrete will bring the moisture back to the joint very quickly. 58 . Use a larger compressor. Troubleshooting procedures for airblasting. and sand. A heat lance may dry the surface of such a pavement for a short time. Pavement that is saturated must be allowed to dry before resealing.d. Air not removing dust. Joint seal materials will not adhere well to dirty or damp joints. Extreme care must be taken to keep the heat lance from remaining in one location for more than 1 to 2 s. Table 20. If the joints are slightly damp.
installed before backer rod installation. All required operator safety equipment must be used. This may include goggles.3. install. the primer installation process must achieve the following: ! Primer must very thinly and uniformly coat all joint surfaces to which sealant must bond. bubbles will form in the sealant as the gas tries to escape. must be dry and tack-free. and respirators. Only a minimum amount of time must be 59 . Prepared joints that are left open overnight must be airblasted again and reinspected for cleanliness and dryness.TECHNOLOGIES HOME PRINT BOOKMARKS 4. and shape sealant material.4 Material Preparation and Installation Objective: To properly install backer rod in clean joint channels and to adequately prepare. generally resulting in a thinner coat. If hot-applied sealant is installed before the primer has dried. since as it dries. Primer. 4. Manufacturers' recommendations for installation methods and safety procedures must be followed. The preparation and sealing operations should be scheduled so that joints are cleaned and left open a minimum amount of time before resealing. 1990). it gives off gas (ACI. protective clothing. Spray equipment is much more efficient. and spray nozzles can be designed to coat only the upper joint wall surface. gloves. It is critical that the primer be allowed to dry. ! Primer should not be wasted by applying thick coats or covering non-essential concrete surfaces.5 Installing Primer To effectively and economically prime joint surfaces. Primer can be installed using a brush or spray equipment.
Joint reservoirs and pavement surfaces must be completely clean before backer rod is inserted. and pavement temperatures. It helps keep the sealant at its design thickness. The backer rod serves two purposes. Polymers used in some hot-applied sealants are susceptible to damage from overheating and from extended heating. air.1 Installing Backer Rod Backer rod should be installed immediately after airblasting and immediately before placing the sealant. Hand-held. and pavement moisture conditions. the manufacturer's recommendations must be followed regarding minimum placement temperatures. sealant heating temperatures. Check with sealant manufacturers for exact heating time and temperature limits. To perform properly and reduce sealant stress.4. Therefore. No matter how good the joint preparation has been. extended sealant heating. they should be marked for recleaning. depending on the sealant properties. The allowable time such sealants may remain at application temperature ranges from 6 h to 5 days. and it keeps sealant from bonding to the bottom of the joint reservoir. Both thicker sealant and bonding to the reservoir bottom place additional stress on the sealant. If unclean joint walls are noted during backer rod installation. calibrated infrared thermometers can be used to easily check sealant. Recommended application temperatures for rubberized asphalt sealants generally range from 185 to 200oC. Most sealant manufacturers recommend installing sealant when the pavement is dry and the air temperature is 4oC and rising. improper sealant installation can result in rapid seal failure.TECHNOLOGIES HOME PRINT BOOKMARKS allowed to pass between backer rod installation and sealant placement. the installed backer rod must meet the following requirements: 60 . 4.
Many methods have been used to insert backer rod into joints. 6. 2. 61 . as shown in figure 16. Have enough rod sizes available to fit all of the joint widths at the project. Cut the rod to the proper length. Tuck the rod loosely into the joint and push the rod into the joint by rolling the installation tool along the joint. The steps for the most commonly used and successful method of installing backer rod are as follows: 1. ! The surface of the rod must not be damaged during installation. ! The rod must be compressed in the joint sufficiently that the weight of uncured sealant or the tooling operation do not force it down into the reservoir before curing. ! No gaps should form between backer rods that are butted together in a joint or at a joint intersection.TECHNOLOGIES HOME PRINT BOOKMARKS ! The backer rod must be compatible with and appropriate for the sealant. 4. Using a screwdriver may damage the surface of the rod and result in bubbles forming in the sealant. 5. Use a long-handled installation tool with a largediameter central disk that fits into all joints and does not cut or damage the backer rod. making sure no gaps exist between segments of backer rod. 3. Roll over the rod a second time with the installation tool to ensure proper depth. ! Backer rod must be at the depth required in the plans. Insert one end of the proper size of rod into the end of a joint. ! The rod must be dry and clean. ! No gaps should be evident between the backer rod and joint walls. Automated equipment is most effective for continuous joints where only one size of backer rod is generally needed. self-guided installation equipment. ranging from poking it in with a screwdriver to using automated.
7. Backer rod installation. 62 . Possible solutions to common problems encountered when installing backer rod are described in table 21. 1984). In sections where the rod does not fit tightly to the joint walls. Certain rod materials are more compressible and require additional tool depth. gaps may form at joint intersections and result in sealant failure. That rod is then cut at the intersection with longitudinal joints and the rod is installed in the longitudinal joints. The depth of the installation tool must be slightly greater than the required depth of backer rod because the rod compresses slightly when installed (Blais. better results are obtained if rod is installed in the entire length of the transverse joints. When transverse and longitudinal joints are being sealed in one operation. install larger diameter backer rod.TECHNOLOGIES HOME PRINT BOOKMARKS Figure 16. since as the material relaxes. Stretching and twisting of backer rod must be minimized during installation.
low-pressure airstream. Troubleshooting procedures for backer rod installation. dry. when installed. blow out the dirt using a clean. 4. If rain interrupts the sealing operation. Damp or wet backer rod must be removed from the joints and replaced with dry rod after the reservoir is completely dry and has been recleaned. Ensure that installation tool is smooth.2 Sealant Installation When the joints are clean. When dirt has re-entered the joints after the backer rod has been installed. dirt and sand can be blown into the cleaned joints. Repeat passes with the installation tool. Do not stretch the rod when installing. taking care not to force the rod deeper into the joint. Use a larger diameter rod. Problems Encountered Possible Solutions Rod is tearing (slivers formed) Use a smaller diameter backer rod. Side gaps are evident or rod is slipping or is easily pushed down in joints. Use a larger diameter roller. Rod depth is inconsistent.4. reclean the open joints before installing the sealant. the backer rod is installed and. if the temperatures are within the required limits.TECHNOLOGIES HOME PRINT BOOKMARKS Table 21. Rod is shrinking in joint. or moisture can enter the joints. sealing can begin. Check the installation tool for depth. If delay occurs before installing the sealant. The sealing operation should progress quickly and result in a seal with the following characteristics: 63 . Gaps are forming between rod ends.
TECHNOLOGIES HOME PRINT BOOKMARKS ! Prevents infiltration of water through the joints. Hot-Applied Sealant To install hot-applied sealant that successfully meets the above requirements. ! Cannot be picked up or spread on adjacent pavement surfaces by tires or the action of power-vacuum rotarybrush pavement cleaning equipment after the specified curing period. ! Is not cracked or split. ! All temperature gauge sensors should be cleaned and accurately calibrated. ! Remains resilient and capable of rejecting incompressible materials at all pavement temperatures. ! Has no bubbles or blisters. small stones. dirt. Suitable cleanup and safety procedures.applicator should be checked for the following properties and modified if necessary: ! Carbon buildup on the sides of the heating chamber should be removed. the melter. and similar contaminants. 64 . proper heating and installation methods must be used. Prior to heating sealant. ! Provides a finished exposed joint surface that is nontacky and will not permit the adherence or embedment of dust. Heating the Sealant Hot-applied sealant performance can be significantly changed by the procedures used to heat and maintain its temperature during installation. must also be followed to ensure worker protection and properly functioning equipment. as described in appendix C. ! Maintains a tight bond with the sidewalls of the joint. ! Is well bonded to the joint walls.
TECHNOLOGIES HOME PRINT BOOKMARKS Heating should be scheduled so that the sealant will be at the recommended temperature when the sealing operation is to begin. Supervisors and equipment operators can use infrared sensors to check pouring temperatures at the nozzle. 4. Check to ensure that the pavement temperature is above the minimum recommended installation temperature and above the dew point. it may cool before it fills the voids in the concrete. the following guidelines should be adhered to: 1. Keep the heating oil temperature no more than 24oC above the safe sealant heating temperature stated on the sealant packaging. If the sealant is installed below this temperature. 3. 2. If sealant is heated above the safe heating temperature. The recommended pouring temperature is the temperature of the sealant that will achieve the best performance. During initial heating. and all sealant operators must be made aware of it. Therefore. and a poor bond may result. it should not be used because rubberized sealants break down and become very thin or very stringy when heated above this temperature. Recommended pouring temperatures vary between sealant manufacturers and types. the pouring and safe heating temperatures of the sealant in use should be obtained from the sealant packaging. The procedures listed below should be followed during installation. Keep sealant temperatures between the recommended pouring temperature and the safe heating temperature printed on the sealant packaging. 65 . Start the agitator as soon as possible. 1. Do not hold the sealant at application temperatures for a long period before using it.
Regularly check the sealant temperatures and adjust as necessary. Check the temperature of the sealant at the nozzle and adjust the melter controls to obtain the recommended pouring temperature at the nozzle. Watch for carbon buildup on the sidewalls of the heating chamber. Methods of Installation Trial installation of at least 15 transverse joints should be completed using the methods scheduled for use in cleaning and installing sealant on each project. 66 . This is a sign of overheating. 5. A similar test can be conducted on silicone and other chemically cured materials after curing is complete. 2. 4.TECHNOLOGIES HOME PRINT BOOKMARKS 2. the remaining joints should be cleaned and resealed in the same manner as the trial joints.. The following installation practices are recommended: 1. Upon approval. 1985). or that remains tacky and shows signs of breakdown. 3. as shown in figure 17 (Darter et al. Sealing should begin only when the air temperature is 8oC and rising and the air temperature is above the dew point. Pour the sealant with the nozzle in the joint so that the joint is filled from the bottom and air is not trapped beneath the sealant. The sealed trial joints should be inspected after curing and approved or rejected prior to sealant placement. Hot-applied seals can be cut on three sides after cooling for a 50-mm length and can be stretched to observe material and adhesive properties. Do not use sealant that has been overheated or heated for an extended period of time. Apply the sealant in one continuous motion while moving the wand in a way that the sealant flows out behind the wand.
Recirculate sealant through the wand into the melting chamber when not applying sealant. Apply sealant in one pass.TECHNOLOGIES HOME PRINT BOOKMARKS Figure 17. 4. 3. If additional sealant is required in low sections. Inform the backer rod installation crew if leaks are occurring at backer rod joints. it should be added as soon as possible. filling the reservoir to the recommended level. Hot-applied sealant installation. 67 .
Sealant and oil temperatures can reach 200oC and can cause serious burns. Have operators wear protective gloves and clothing. If carbon is built up on the heating chamber walls. Cleanup Requirements Follow the melter–applicator manufacturers' instructions as to the frequency of cleaning. remove it completely by scraping and flushing.TECHNOLOGIES HOME PRINT BOOKMARKS 5. and waste the first 10 L of the day to remove any traces of solvent. Flush the pump and hose with solvent. and sealant that has not bonded to the joint walls. These include the following: 1. if recommended. and low operator fatigue. 68 . Do not allow construction equipment or vehicle traffic onto the pavement until the sealant has set and there is no danger of tracking or stone intrusion. sealant that remains tacky. Be careful when loading blocks of sealant— splashing can occur. little waste. Use equipment and installation practices that result in consistent sealant thickness. 7. areas of sunken sealant. 6. Watch for bubbles. during. 2. Several safety precautions should be followed before. and solve these problems as soon as they are identified. Safety Precautions Obtain the MSDS' for each sealant material and follow the s worker protection and disposal instructions outlined in them. Support plates on the wand tip may be useful for this purpose. and after installation. Several solutions are listed in table 22. Dispose of the wasted sealant/solvent solution properly.
Gap remains between rod and wall. Gap remains between backer rod ends. Use an experienced operator. Provide a hose support. Use a wand with a shut-off valve at the nozzle. Problem Encountered Possible Causes Reaction with backer rod. Possible Solutions Use nonreactive backer rod. Use a nozzle with a depth control plate. Reduce the agitator speed. Add sealant material. Joint width is variable. Sealant recess is not consistent 69 . Use proper diameter backer rod. Troubleshooting procedures for hot-applied sealant installation. Bubbles in sealant Moisture in joint. Bubbles in melter. Sealant is deeply sunken in joint Do not stretch rod. Fill joints from the bottom. Allow the joints to dry. Install sealant above the dew point. Change the rod installation method or rod diameter. Air trapped by sealant. Rod slipping into joint.TECHNOLOGIES HOME PRINT BOOKMARKS Table 22. Damaged backer rod. Hoses are unmanageable. Operator movement is uneven. Operator control is poor. Install rod carefully.
Replace with uncontaminated sealant. Remove and replace with fresh sealant. Wait for warmer conditions. Remove sealant. Wait for concrete to dry. or other sealant. Insulate and heat hoses. Check melter temperatures. Pavement temperature is too low. Problem Encountered Possible Causes Joint walls are not clean. Possible Solutions Remove all old sealant. dirt. 70 . heat transfer oil. Insulate and heat hoses. and other contaminants. Troubleshooting procedures for hot-applied sealant installation (continued). Sealant is not sticking to concrete walls There is moisture on the walls from rain. oil. Sealant temperature is too low. Clean and flush kettle. dust. Maintain recommended sealant temperature. Sealant has been overheated or heated too long. solvent. Sealant remains tacky after installation Kettle contaminated with asphalt.TECHNOLOGIES HOME PRINT BOOKMARKS Table 22. or condensate. Install above the dew point temperature. dew. sawing slurry.
Make sure the appropriate hoses (manufacturer recommended) are used. silicone sealant is pumped from storage containers through compressed-air-powered pumping equipment to a wand with an application nozzle. cold-applied sealants. Do not overheat the sealant— it is flammable. These include polysulfides. 1990). Premature curing can result from such exposure.TECHNOLOGIES HOME PRINT BOOKMARKS 3. Methods for Installation The following practices have been used successfully and are recommended for installing silicone sealants: 71 . Excessive breathing of fumes or skin contact with coal tar compounds may cause irritation (ACI. and silicones. 4. The discussion in this manual is limited to the installation of one-part. Consult manufacturers' literature for installation recommendations for each sealant type. polyurethanes. Cold-Applied Sealant Several types of sealant are installed without heating. ! Limit the exposure of the sealant to air and moisture. ! Load the sealant in the apparatus in a manner that keeps bubbles from becoming trapped in the sealant. 6. Two important precautions should be observed when loading silicone into an approved pumping apparatus. 5. The sealant is pumped from 19-L buckets or 208-L drums. Follow manufacturers' safety instructions when using coal tar compounds. as shown in figure 18. Loading Sealant in Pumping Apparatus Typically. Follow disposal instructions for cleaning solvent and wasted sealant.
moving steadily along the joint. nozzle type. or other suitable instrument. Tool (i. 4.TECHNOLOGIES HOME PRINT BOOKMARKS Figure 18. or leaving unfilled joint space (USAF. Apply the sealant in one continuous motion. 72 .e. tearing. 5. and nozzle diameter to control the speed of application. Silicone sealant installation. a dowel. and push the bead along the joint rather than draw it with the gun leading. 2. 1. so that the joint is filled from the bottom and air is not trapped beneath the sealant. so that a uniform bead is applied without dragging. Adjust the pump rate. Pour the sealant with the nozzle in the joint. Use a nozzle that applies sealant at a 45o angle. form a concave surface in) the non-selfleveling sealant using a piece of oversized backer rod. 1983). 3.. plastic tubing on a fiberglass rod.
Watch for bubbles. 73 . forming a uniform concave surface with no wasted sealant on the pavement surface. a non-uniform surface. and solve these problems as soon as they are identified. 9. 7.TECHNOLOGIES HOME PRINT BOOKMARKS 6. Allow non-self-leveling sealant to become tack free and self-leveling sealant to skin over before opening the pavement to traffic. The bottom of the concave tooled surface should be at least 7 mm below the pavement surface. Non-self-leveling silicone sealant is generally tack free within 90 minutes at temperatures above 4oC. If large pavement deflections are expected. The surface of the self-leveling silicone sealant must be recessed 7 to 10 mm below the pavement surface and should never be exposed to traffic wear. press the sealant around the backer rod. allow a longer cure time. Follow the sealant pump manufacturer' instructions for cleaning frequency s and required solvents. and other installation deficiencies. Self-leveling silicone sealant typically skins over within 60 minutes and cures in about 21 days. sunken sealant. 8. Several solutions are listed in table 23. When tooling is required. Cleanup Requirements Cleaning of the applicator equipment apparatus will be required if the sealant begins to cure in the pump or hose. and it cures within 7 days.
Gap between backer rod ends. Use another strike-off tool. Use larger diameter backer rod. Air was trapped by the sealant. Tooling was inadequate. Sealant is deeply sunken in joint Installed sealant contains bubbles Bubbles in pump lines. Gap between rod and wall. dust. Rod is slipping into joint. or rod diameter. 74 . Install above the pavement dew point temperature. sawing slurry. Use more tooling care. Use nonreactive backer rod. Moisture remains on the walls from rain. and other contaminants. or dew.TECHNOLOGIES HOME PRINT BOOKMARKS Table 23. tool. Fill the joint from the bottom. Damaged backer rod. Do not stretch rod. dirt. Wait for concrete to dry. Reaction with backer rod. Problem Encountered Possible Causes Joint walls are not clean. Troubleshooting procedures for cold-applied sealant installation. Change rod installation method. oil. Sealant is not sticking to concrete walls Possible Solutions Remove all old sealant. Install rod carefully. Set the pump diaphragm into sealant better. condensate.
Sealant recess is not consistent Nozzle tip is wrong size. Use another strike-off tool (large backer rod. Problem Encountered Possible Causes Operator control is poor. Troubleshooting procedures for cold-applied sealant installation (continued). 75 . Surface tooling is poor. plastic or rubber tubing on flexible handle). Reduce nozzle tip size to easily insert to top of backer rod. Use a "dog leg" applicator.TECHNOLOGIES HOME PRINT BOOKMARKS Table 23. Joint width is variable. Possible Solutions Use a more experienced operator. User more tooling care. Operator movement is uneven.
since at that time. such as the one in figure 19. alone or in conjunction with the IA-VAC joint seal tester. a graph of seal effectiveness versus time can be constructed. joints will be near their maximum opening and. Eq. 77 . Percent length allowing water to enter joints. 9 After a few inspections. and subsequent evaluations should be conducted at regular intervals to chart the rate of failure and plan for subsequent maintenance. adhesion loss can be seen more easily. The IA-VAC system can easily determine joint seal effectiveness in a consistent manner any time of the year until failure rates become moderate or greater (Steffes. a small representative sample of the pavement section should be selected for the evaluation. As discussed in section 2. 1993). as a result.1.TECHNOLOGIES HOME PRINT BOOKMARKS 5.0 Evaluation of Joint Seal Performance Monitoring the performance of joint seal treatments is good practice. A mid-winter evaluation is highly recommended. Visual evaluation. At least one inspection should be made after the first winter. The joint seal effectiveness can then be calculated using the following equation: %Leff ' 100 & %L fail where: %Leff = %Lfail = Percent joint seal effectiveness. can provide seal performance information. and it can be done rather quickly (in 1 or 2 h) with fair accuracy. Resistance to the entrance of water and debris to the joint should be measured by noting the percentage of water resistance loss using equation 1 provided earlier. Visual evaluation methods will become more necessary as failure rates increase.
H. will help to indicate when additional joint seal treatment is required. Figure 19. For example. estimates of the time to 50 percent effectiveness could be obtained for planning the resealing of the remaining sites. Example joint seal deterioration chart (See next page) 78 . commonly 50 percent. Moreover. A budget for resealing in the next 2 years could be prepared for sites E and F. and I.TECHNOLOGIES HOME PRINT BOOKMARKS A minimum allowable effectiveness level. a resealing plan using figure 19 could include immediate resealing of sites G.
TECHNOLOGIES HOME PRINT BOOKMARKS 100 90 Seal effectiveness. months Site A Site B Site C Site D Site E Site F Site G Site H Site I . % joint length 80 70 60 50 40 30 20 10 0 0 10 20 30 40 50 60 70 80 Times.
Information regarding the availability of specifications can be obtained from the agencies listed below.gov www.dot. DC 20001 202-624-5800 www. Specifications are revised frequently. and the sponsoring society should be contacted to obtain the latest edition. PA 19428 610-832-9500 www.org U.gov 79 .S. ASTM Specifications American Society for Testing and Materials 100 Barr Harbor Drive West Conshohoken.astm. These specifications are based on specifications prepared by the American Society for Testing and Materials (ASTM). the American Association of State Highway Transportation Officials (AASHTO). VA 22161 800-553-6847 www.ntis.aashto.org AASHTO Specifications American Association of State Highway and Transportation Officials 444 North Capitol Street. Federal Specifications National Technical Information Service 5285 Port Royal Road Springfield.fhwa. and by States having significant joint resealing experience. NW.TECHNOLOGIES HOME PRINT BOOKMARKS Appendix A Material Testing Specifications Material testing specifications are listed in tables A-1 and A-2. Suite 249 Washington.
TECHNOLOGIES HOME PRINT BOOKMARKS Table A-1.) Bond (-29oC.) or (-29oC.) or (-29oC. % recovery) Bond (-18oC. 100% ext. 50% ext. 50% ext. mm) Resilience (25oC. Test Criteria Test Description a Other ASTM D 1190 < 90 <5 AASHTO M 173 < 90 <5 ASTM D 3405 < 90 <3 > 60 Pass 5 cycles Pass 5 cycles Pass 3 cycles Pass 3 cycles Pass 3 cycles Pass > 40 Pass 3 cycles Standard AASHTO M 301 < 90 <3 > 60 Federal SS-S-1401 < 90 <3 > 60 Low Modulus State Specification 110 to 150 <3 > 60 Cone penetration (25oC. dmm) a 1 dmm = 0. dmm) Flow (60oC. 100% ext.) Bond (-18oC. 200% ext.1 mm 80 . Rubberized asphalt specifications.) Asphalt compatibility Cone penetration (-18oC.
6 mm slump > 50 <5 Pass Self-Leveling Type 1. nonimmersed. Test Method Silicone Type a Non-Sag Rheological properties Extrusion rate.. smooth > 50 <5 Pass Test Description < 25 > 30 No flow > 600 < 310 Pass < 25 > 30 No flow > 600 < 310 Pass > 75 > 75 a 21-day cure time. type A2) Flow Ultimate Elongation. h Bond (-29oC. 100% ext. type A2) Hardness (23oC. kPa Accelerated weathering (500 h) Resilience. oven-aged) Hardness (-29oC. % ASTM D 2202 ASTM C 1183 ASTM C 679 ASTM D 5893 ASTM C 661 ASTM C 661 ASTM D 5893 ASTM D 412(C) ASTM D 412(C) ASTM C 793 ASTM D 5893 <7. % Tensile stress at 150% strain (23oC). 81 .TECHNOLOGIES HOME PRINT BOOKMARKS Table A-2. mL/min Tack-free time. ASTM D 5893 silicone sealant specifications. immersed.
Appendix B Sample Cost-Effectiveness Calculations
Sample worksheets for cost-effectiveness calculations are presented in this section. The forms included in section 3.11 are used to illustrate the method discussed in that section. Data used for calculation of cost-effectiveness are listed below and in tables B-1 through B-3. Sealant Type = Shape Factor = Joint Width = Joint Length to Seal = Project Length = Primer = Estimated Lifetime = Plow Rate = Saw Rate = Airblast Rate = Sandblast Rate = Backer Rod Install Rate = Sealant Installation Rate = Labor Rates = Supervisor Rates = Self-leveling silicone sealant 2:1 13 mm 6.0 km 4.0 km None required 8 years 160 m/h 84 m/h 152 m/h 114 m/h 165 m/h 165 m/h $150/day $200/day
The sealant coverage rate is calculated in the following equation: CR ' 0.001 1.2 1.0 12.7 6.4 ' 0.0975 where: CR WF W T ST = = = = = Coverage rate, L/m Wastage factor Joint width, mm Thickness of sealant Surface type constant
= = = =
1.2 12.7 6.4 1.0
Table B-1. Example material and shipping costs.
Material Cost, $/unit a Sealant, L Backer rod, m Blasting slag, kg Primer, L Total material cost: 7.40 0.011 0.11 -0Coverage rate, unit/m b 0.0975 1.05 0.30 -0Length required, m c 6,100 6,100 6,100 -0Total cost $/material axbxc 4,401 211 201 -04,813
Material, unit
100 1.380 1.5 3.5 4.5 6 3. Example labor costs.800 1.6 4.6 Total Cost. $ dxexf 2. Wages.380 13.TECHNOLOGIES HOME PRINT BOOKMARKS Table B-2.800 2.585 Crew Labor 85 .500 525 1.050 1. $/day d Supervisor Traffic control Plowing Sawing Initial airblast Sandblast Final airblast Backer rod Sealant installation Total labor cost: 200 150 150 150 150 150 150 150 150 Number in Crew e 1 1 2 1 2 2 2 2 2 Days Required f 14 14 5 3.050 1.
0 5. $ gxhxi 6. Daily Cost.200 920 2. Example equipment costs.TECHNOLOGIES HOME PRINT BOOKMARKS Table B-3.5 7. $/day g Traffic control Joint plow Concrete saw Air compressor Sandblast equip.300 750 1.575 1. Other trucks Total equipment cost: 450 150 225 175 200 200 100 Number of Units h 1 1 2 1 1 1 2 Number of Days i 14.125 1.670 Equipment 86 .800 14.0 4.5 6.6 14.0 3. (including compressor) Installation equip.0 Total Cost.
05 5 1% 0. Total material cost [table B-1] Total labor cost [table B-2] Total equipment cost [table B-3] User delay cost Total resealing cost Project length.1 5. Annual Cost ' C E 1 %E D 1% E D & 1 Avg. resealing cost. together with the same preparation methods listed above and a shape factor of 1:1.05 5 & 1 ' $1.367 Average Annual Cost. lane-km Avg.585 $ 14.336 (A) 6. $/lane-km $ 1.966 87 .05 1% 0.05 1% 0.367 Using an ASTM D 3405 sealant that costs $1.250 ========== $ 35.834 0.TECHNOLOGIES HOME PRINT BOOKMARKS Table B-4.05 (B) (C) (D) (E) $ $ $ Avg. the computed average annual cost is: Avg. $/lane-km Estimated lifetime of seal. years Interest rate (typically 0. Example cost-effectiveness calculations.05) $ 4. Annual Cost ' 8.05 8 & 1 ' $1.05 8 1% 0.10/L and lasts 5 years.510 0.793 8 0.670 $ 2.831 $ 13. Annual Cost ' 8.
In addition. C. and safe usage and disposal.1. 2. individual crews should be made aware of all safety precautions associated with the materials and equipment with which they are working. such as vests and hard hats. MSDS' s should be obtained from the manufacturers of all materials to be installed.1 Hot-Applied Sealants Hot-applied sealants require that several safety precautions be followed: 1. fire and explosion data. should always be worn by crews and supervisors during sealing operations. Be careful when loading blocks of sealant— splashing may occur. Do not overheat the sealant— it is flammable.TECHNOLOGIES HOME PRINT BOOKMARKS Appendix C Material and Equipment Safety Precautions Mandated highway safety attire. C. Sealant and oil temperatures can reach 200oC and can cause serious burns.1 Materials In order to protect the health and well-being of maintenance workers who handle the various sealant materials. 89 . and these sheets should be reviewed by those handling the materials. Every effort should also be made to determine the type of sealant material to be removed and to address any safety hazards that it may present. These sheets provide important information about health hazards. Have operators wear protective gloves and clothing. reactivity data. 3.
4. Follow manufacturers' safety instructions when using coal tar compounds. Excessive breathing of fumes or skin contact with coal tar compounds may cause irritation or possibly more serious health problems. 5. Use care with any solvents required for cleanup. 6. Dispose of diluted or wasted sealant as specified in the MSDS. C.1.2 Cold-Applied Sealants When working with cold-applied sealants, care should be taken to protect workers from skin, eye, or internal contact with sealant materials. MSDS and the manufacturer's recommendations should be consulted to determine specific safety requirements for each sealant material.
Appendix D Inspection Checklists for Construction
This section is intended for use by inspectors of resealing processes, as well as by supervisors and contractors. It contains discussions of planning, equipment, and procedures critical to the successful completion of a resealing project. Checklists pertaining to each step of the process, including planning, equipment, material preparation, joint preparation, sealant installation, final inspection, and safety precautions, are included. Field experience has shown that each step in the resealing process requires careful supervision and inspection. An inspector must continually observe the various operations to ensure that proper procedures are being performed. In most cases, it is the contractor's responsibility to effectively clean and reseal the joints, and it is the inspector's responsibility to continually monitor the work and ensure that corrections are made if requirements are not met.
D.1 Preconstruction Plans and Specifications
Plans must be prepared and distributed to the inspectors and the supervisors of the installation crew. It is recommended that the inspectors and the construction supervisors meet before work begins to discuss the plans and specifications. Information that must be contained in the plans includes the following: G 1. Project layout, including stationing and slab lengths.
2. 3. 4. 5. 6. 7.
Original joint reservoir dimensions, including existing variability. Original sealant material type. Location and type of required pre-resealing repairs. Required reservoir dimensions. Required sealant thickness. Required sealant recess below pavement surface.
Specifications may be based on adherence to designated procedures, on achieving a quality end product, or a combination of the two. Information that must be contained in procedure-based specifications includes the following: G G G 1. 2. 3. Lot testing requirements. Delivery and storage requirements. Repair methods and materials for pre-resealing repairs. Equipment requirements. Material requirements. Preparation procedure requirements. Installation procedure requirements. Weather condition limitations. Traffic shutdown requirements. Safety requirements. Material disposal requirements.
If end-result specifications are used, the following information must be included: G G G G 1. 2. 3. 4. Lot testing requirements. Delivery and storage requirements. Repair methods and materials for pre-resealing repairs. Required results of each preparation procedure and acceptance/rejection criteria.
Required results of the installation process and acceptance/rejection criteria. In most cases. 7. The condition and effectiveness of each piece of equipment should be checked during trial installation and at the beginning of each day of preparation and installation. During pre-installation inspection. indicating that the equipment is acceptable for installing the sealant. A list of proposed equipment should be submitted for approval before installation. Material disposal requirements. 93 . the inspector should check all equipment to be used on the project. 8. and the following inspection process is based on a combination of the two. a combination of procedure-based and end-result specifications is used. If questions arise about the suitability of the equipment. Limitations of traffic shutdown. 9. D. Weather condition limitations. Safety requirements.TECHNOLOGIES HOME PRINT BOOKMARKS G G G G G 5. An example of installation acceptance criteria is included in section D. Criteria for equipment effectiveness are listed in the sections below. as well as during joint preparation and sealant installation.4. making sure that each piece meets the requirements of the project specifications or the suggested requirements listed previously in table 11. a statement from the sealant manufacturer should be supplied.2 Equipment Inspection All equipment must be inspected and approved before the project begins. 6.
Safety requirements for all equipment and procedures (including material disposal requirements).3 Field Installation Inspection After all required spall repair. 7. Exact locations and number of joints to be resealed (boundaries should be clearly marked). The following inspection checklist can be used to ensure that joint preparation is completed properly 94 . Sealant manufacturers' instructions should be followed when preparing joints unless noted otherwise in the plans and specifications. D. 5. It is recommended that the inspectors and supervisors meet before work begins to discuss the following subjects: 1. slab stabilization. Procedures in the event of wet or cold weather. Methods required for cleaning and resealing joints (if procedure-based specification). Procedures in the event that seal quality requirements are not met. Any localized variations from the specified methods. Criteria for approval of all cleaning and installation equipment and processes. final cleaning. the resealing process can begin.3. 8. Final criteria for approval of resealing work. refers to sealant removal. 9. 3. 2. joint refacing. 6.1 Inspection of Joint Preparation Joint preparation. as discussed in this manual. and other rehabilitation have been completed and approved. Traffic control requirements and lane closure time limitations. including procedures and penalties for rejection. and backer rod insertion. grinding. load transfer restoration.TECHNOLOGIES HOME PRINT BOOKMARKS D. 4. primer installation.
G No standing water remains in the joints. G All guards and safety mechanisms are functioning properly. oil. G Two passes are made for each joint. G No old sealant. G Worker and driver safety are not compromised. Abrasive blasting: G The nozzle is being held 25 to 50 mm from the pavement. Concrete sawing: G Saw is removing the required amount of concrete and sealant. or dried sawing slurry remains on the joint walls. although not all of these cleaning processes are used. G 1. in many cases. G 4. Waterwashing: G Equipment is removing all sawing slurry and old sealant from the joints. G 3. 95 . G Plow is not spalling the joint edges. G Saw is uniformly cutting to the proper width and depth (depth and width can be checked quickly using a metal template). G Saw is refacing both sides of the joint. directing the nozzle toward one side of the joint for each pass. Joint plowing: G Plow is removing the required amount of sealant. G 2. G All sawing slurry is immediately removed from the joints.TECHNOLOGIES HOME PRINT BOOKMARKS (USAF. 1983).
Primer application: G Primer applicator is applying a thin layer of sealant uniformly over joint faces to receive sealant. G Primer is allowed to dry before backer rod is inserted. dirt. G The operator is wearing required eye and ear protection. dust. the joint is clean and dry.TECHNOLOGIES HOME PRINT BOOKMARKS G G G The blaster does not introduce oil or moisture to the joint. Airblasting: G Equipment is removing all dirt. Following sandblasting.or Staterequired protective devices. and dust from the pavement surface. G 5. Vacuum or compressed-air cleaning: G Cleaning equipment is removing all old sealant. 96 . and sand from the dry joint reservoir. especially on windy days or when traffic is moving next to the cleaned joints. G 6. G The airblaster does not introduce oil or moisture to the joint (check for oil by directing the airstream onto a tire or a piece of paper and noting any discoloration). G Following airblasting. G 7. sand. G Debris has no potential for re-entering the joints. all joint walls exhibit freshly exposed concrete. The operator is using all OSHA. G All required safety protection equipment is in use and is operational.
TECHNOLOGIES HOME PRINT BOOKMARKS G 8. Backer rod installation: G The rod is inserted into the joint uniformly to the required depth without stretching or tearing it. G The backer rod is not pushed into the joint by the airstream. at a minimum. 97 . at joint intersections. particularly if temperatures and humidity levels have been at or near the dew point. G The rod is compressed in the joint enough that the weight of the uncured sealant or installation equipment or tooling equipment will not force it down into the joint. or between rod segments. Check frequently for dew that may collect in the joints and remain after the surface is dry. Depth can be checked using a template (slivers of rod in the joint indicate that the rod is too large). dew. they should be recleaned in a manner that restores cleanliness. dirt. Low-pressure air cleaning : G When needed. Moist backer rod should be replaced after drying and joint recleaning. This may require sandblasting and airblasting or merely airblasting. or oil. If cleaned joints are recontaminated by rain. all dust or dirt that has reentered clean joints that contain backer rod is blown out. G The rod remains tight in the joint without gaps along the sides. Cleaned joints that are left overnight should. be airblasted again. G 9. Water on the joint walls during sealing will severely reduce the ability of the sealant to bond to the walls and can result in bubbles in some sealants. G A larger diameter rod is used in wide joint sections.
The recommended sealant application temperature. The following section is a checklist for inspection of joint sealant installation.2 Inspection of Joint Sealant Installation The inspector should watch for several items prior to and during installation of the sealant material. A possible pattern that could be used is the following. 2. 3. 2.1 Hot-Applied Sealant Installation Inspection When inspecting the installation of hot-applied sealant materials. This information can be obtained from sealant manufacturers and from the project plans and specifications: G G 1. 4. etc. The safe sealant heating temperature.TECHNOLOGIES HOME PRINT BOOKMARKS One method that an inspector can use to communicate the need for additional preparation at a particular joint is to mark near it with a particular color of paint (USAF. The contractor or supervisor can use green spray paint to indicate that the problem is repaired and the inspector should re-examine the joint for approval. 1983). the information listed below must be determined before heating begins. not tooled correctly. Red— Joint is not properly cleaned. D. Blue— Backer rod is not tight or is not at proper depth. bubbles in sealant. 1. 98 . Yellow— Repairs must be made to joint before sealing.2. D. tacky sealant.3. Orange— Joint is not the proper size. 5. Brown— Improper sealing technique (too full.3. sealant not bonded. too low.).
and the penalties associated with rejection. Acceptable test results for all materials to be installed. The air temperatures allowable for sealing. 2. 4. The required sealant recess below the pavement surface. 5. The melter–applicator maintains the sealant at the required temperature without overheating. All backer rods remain tight in the joint at the correct height with no gaps. 4. The average sealant curing time and the time before traffic can be allowed on the pavement after resealing. Sealant leaving the nozzle is at the application temperature. All thermometers and temperature controls are monitored and functioning properly. G G 8. 7.TECHNOLOGIES HOME PRINT BOOKMARKS G G G G G 3. During installation of hot-applied sealants. G 11. 9. 8. The criteria for acceptance/rejection of resealing work. 7. The required thickness of sealant. The length of time that a sealant can be heated before it begins to break down. The agitator is functioning properly. 9. 6. The operator is not trapping bubbles in the sealant or overfilling or underfilling the joints. 3. The MSDS' s. Spilled sealant is removed from the pavement surface. 5. the following items should be regularly checked to ensure that they meet the requirements: G G G G G G G G G 1. The production date and shelf life of all materials. 6. 99 . G 10. No carbon is built up on the melting chamber walls. All joints remain clean and dry.
4. G 9.2 Silicone Sealant Installation Inspection Prior to installation of silicone sealants. Steps are taken to eliminate the cause of the low sealant. As sealant installation continues. G 11. or the sealant becomes stringy inside the melting chamber. 5. The average sealant curing time and the time before traffic can be allowed on the pavement after resealing. The production dates and shelf life of all materials. the following information should be obtained by the inspector: G G G G G G 1. The air temperatures allowable for sealing. 3. Warning: If white smoke is seen rising from the kettle. This applies especially to D 3406 materials. 6.3.2. The criteria for acceptance/rejection of resealing work and penalties for rejection. G 10. G G 7. The acceptable results of lot tests for all materials.TECHNOLOGIES HOME PRINT BOOKMARKS G 10. The expiration date of the sealant material. The need for tooling the surface of the sealant. Areas of low sealant are not present or are quickly filled. Safety data from the MSDS. 8. The required thickness of sealant. The required sealant recess below the pavement surface. stop the operation immediately and check the sealant temperature. All required operator safety equipment is in use. D. the following items should be regularly checked for compliance with the plans and specifications: 100 . If the sealant remains tacky in the joint long after placement. the sealant has been overheated and should be completely removed from the chamber and wasted. 2.
Areas of low sealant are not present or are quickly filled. 4. All required operator safety equipment is in use. G 10. Backer rods remain tight in the joint at the correct height with no gaps. Steps are taken to eliminate the cause of the low sealant.. forcing sealant against the joint walls and creating a smooth concave surface. The operator is not trapping bubbles in the sealant. 3. 1983): 101 . USAF. and noting the presence and severity of any distresses (Darter et al. 6. G 11. Traffic is not allowed on the pavement until the sealant is skinned over and cannot be damaged. G 7. 9. and controls allow the operator to fill the joint uniformly to the correct level. All joints remain clean and dry. The operator is not overfilling or underfilling the joints (sealant thickness and recess can be checked by inserting a thin ruler through the uncured sealant to the top of the backer rod). G G 5. ensuring that the sealant meets the following criteria. wand. The silicone applicator system is not introducing bubbles to the sealant. 1985. Any sealant that remains on the pavement surface is removed.4 Final Inspection During installation and prior to approval. 2. the resealed joints should be individually inspected.TECHNOLOGIES HOME PRINT BOOKMARKS G G G G 1. Non-self-leveling silicone sealant is tooled immediately. The applicator. G G 8. D.
8. G G 7. 6. Sealant is recessed to the correct depth below the pavement surface (this is critical for silicone sealants. or the action of power-vacuum rotarybrush pavement-cleaning equipment after the specified curing period. or blisters. Sealant is not tacky after curing and will not permit adherence of dust. G G 5.TECHNOLOGIES HOME PRINT BOOKMARKS G 1. 102 . Sealant material contains no cracks. 4. Sealant cannot be picked up or spread on adjacent pavement surfaces by tires. as they are not resistant to traffic wear). bubbles. G G G 2. Sealant is bonded firmly to the joint sidewalls (cured sealant material should not separate from the sidewalls when pulled lightly with the fingertips across the joint). rubber-tired vehicle traffic. or small stones. No debris remains on the pavement surface. 3. Sealant is resilient and capable of rejecting stones at high pavement temperatures. dirt. Sealant spilled on the pavement surface has been removed.
and installation equipment.O. Box 2338 Wichita. and any required protective equipment. Sealant Material E.1. should be available from all sealant manufacturers. Crafco Way Chandler. Addresses and phone numbers are given for manufacturers and suppliers who can provide the inquirer with information regarding material properties.crafco. AZ 85226 (602) 276-0406 (800) 528-8242 www. and local suppliers.com . 300 Industrial Drive. IL 60140-0338 (847) 683-4500 (800) 342-5976 www. Meadows. KS 67220 (316) 828-8399 (800) 654-9182 www.kochmaterials.TECHNOLOGIES HOME PRINT BOOKMARKS Appendix E Partial List of Material and Equipment Sources This section contains information for contacting several manufacturers of sealant materials.R. Inc.1. MSDS' that describe the material components.com 103 W.com Koch Materials Company 4111 East 37th Street North P. Box 338 Hampshire. E. any hazardous s properties.wrmeadows. recommended installation practices.1. safety procedures. Manufacturers of Hot-Applied Rubberized Asphalt Sealant Crafco Incorporated 6975 W. backer rod.
Crafco Way Chandler.com Industrial Thermo Polymers Limited 153 Van Kirk Drive Brampton.TECHNOLOGIES HOME PRINT BOOKMARKS E. NC 27597 (919) 269-6500 (800) 345-7279 www.crafco.dowcorning. 501 NMC Drive Zebulon. Manufacturers of Self-Leveling and Non-SelfLeveling Silicone Sealant Crafco Incorporated 6975 W.1. Inc.2.2. Box 994 Midland.1. ON. Manufacturers of Expanded Closed-Cell Foam Rod Nomaco.2. Backer Rod Material E.com E. AZ 85226 (602) 276-0406 (800) 528-8242 www. Canada L7A 1A4 (905) 846-3666 (800) 387-3847 104 . MI 48686-0994 (517) 496-4000 www.com Dow Corning Corporation P.O.nomaco.
2.3.3.com Crafco Incorporated 6975 W.com 105 .steppmfg.O.com E. Manufacturers of Melter–Applicators for HotApplied Sealants Cimline. Sealant Installation Equipment E. MN 55440-1441 (612) 623-6000 (800) 367-4023 www. 12325 River Road North Branch. Inc. 2601 Niagra Lane Minneapolis.crafco. MN 55447 (800) 328-3874 www.com Stepp Manufacturing Company. Inc. Crafco Way Chandler. P.TECHNOLOGIES HOME PRINT BOOKMARKS E. AZ 85226 (602) 276-0406 (800) 528-8242 www.graco. MN 55056 (612) 674-4491 (800) 359-8167 www. Box 1441 Minneapolis.3.1.cimline. Inc. Manufacturers of Pump Applicators for ColdApplied Sealants Graco.
Compression seals–Preformed seals. divided by the number of days in that period. 107 . that can be compressed and inserted into concrete joints for sealing purposes.TECHNOLOGIES HOME PRINT BOOKMARKS Glossary Adhesion failure–Complete loss of bond between a sealant material and the concrete joint wall. Channel face–The vertical concrete sidewall of a sawed joint sealant reservoir. greater than 1 day and less than 1 year. D-cracking–The breakup of concrete due to freeze-thaw expansive pressures within certain susceptible aggregates (also called durability cracking). generally made from neoprene. Average daily traffic (ADT)–The total traffic volume carried by a pavement during a given period (in whole days). Blowups–The result of localized upward movement or shattering of a slab along a transverse joint or crack. allowing the corner to move independently from the rest of the slab. Allowable extension–The amount of stretching of a sealant material under which performance is estimated to be adequate. Corner break–A diagonal crack forming between transverse and longitudinal joints that extends through the slab.
Flow–The sinking of unstable sealant into a sealant reservoir. such as stones. Joint sidewalls–The vertical concrete edges of a sawed joint reservoir. Load transfer–The transfer of load across a joint or crack in concrete pavement resulting from aggregate interlock. Extruded–Forced through a die to give the material a certain shape. Joint growth–The gradual increase in joint width resulting from the filling of joints with incompressible materials during cold cycles. as stones sink into and become fixed in soft sealant material. 108 . taking into account the effects of both inflation and interest rates on expenses over the life of the project. and dirt in a crack or joint reservoir that is closing. or other load-carrying devices. sand. Horizontal movement–Opening and closing of joints resulting from pavement expansion and contraction. Life-cycle cost analysis (LCCA)–An investigation of the present and future costs of each repair alternative.TECHNOLOGIES HOME PRINT BOOKMARKS Embedment–To become fixed firmly in a surrounding mass. Incompressible material–Material that resists compression. dowels.
concrete dust. and dirt that results from resawing a joint in concrete pavement. Sealant reservoir–The channel along a joint or crack that has been widened by sawing to allow sealant to be placed in it. 109 . and sealant/concrete interface). Sealant system–All components that function to seal joints (i. Subdrainage–Drainage of moisture from beneath a pavement by means of a porous subbase material connected to outlet drain lines.e.. Pumping–The ejection of water and fine materials from beneath a concrete pavement through cracks or joints under pressure from moving loads. preferably using good-quality methods and materials. Refacing–Removing about 1 to 2 mm of concrete from each wall of a sealant reservoir using diamond saw blades.TECHNOLOGIES HOME PRINT BOOKMARKS Overbanding–Spreading a thin layer of sealant (about 38 mm wide) onto a pavement surface centered over a joint or crack at the same time that the sealant reservoir is filled. Resealing–Replacing sealant in joints or cracks. surrounding concrete. sealant material. Sealant/channel interface–The vertical edge of a sealed joint where sealant material and concrete joint face meet. Slurry–The mixture of water. old sealant.
TECHNOLOGIES HOME PRINT BOOKMARKS Track–The spreading of unstable sealant material along the pavement surface by traffic tires. and time. ultraviolet rays. Weathering–Breakdown of sealant material resulting from the effects of moisture. 110 . curling. or pavement faulting. Undersealing–Filling voids beneath a concrete pavement using a pressurized slurry or hot asphalt material. Vertical shear–Vertical stress along the sealant/concrete interface resulting from traffic loading.
Improved Methods for Sealing Joints in Portland Cement Concrete Pavements. and W.D.H. 1985. Rmeili. A." Transportation Research Record 1392.D. Innovative Materials Development and Testing. I. Vol. Methods for Shoulder Joint Sealing. American Concrete Institute Report ACI 504R-90. E. 1984. M. D. Darter. Fowler.C." Public Works.. Carpenter. Volume 1: Project Overview (SHRP-H-352). Federal Highway Administration Report FHWA-TS84-221. FHWA/TX-87-385-1. Research Report 385-1. L.. D. Blais. University of Texas at Austin. 1: Serviceability Requirements. Mangum. and R. Federal Highway Administration. Tirado. and A. Perry.A. J. Meyer. M.J.H. A.M. Center for Transportation Research. Volume 3: Treatment of Cracks in Asphalt Concrete-Surfaced Pavements (SHRP-H111 . W.J. Guide to Sealing Joints in Concrete Structures. 1990. "Problems and Solutions in Rigid Pavement Joint Sealing. Bodocsi.L.R. Barenberg. E.S. E. NCHRP Research Report 1-21. 1986. et al. Minkara. Collins. Arudi.TECHNOLOGIES HOME PRINT BOOKMARKS References American Concrete Institute (ACI). 1993. and G.W. Bugler. 1993. Volume 2: Pothole Repair (SHRP-H-353).. Washington. Value Engineering Study of Crack and Joint Sealing. Evans.H.A.I.W. S. "Analysis of Horizontal Movements of Joints and Cracks in Portland Cement Concrete Pavements. Joint Repair Methods for Portland Cement Concrete Pavements. 1983.. Yrandson. 1987.
Evans. Volume II: Synthesis of Operational Deficiencies of Equipment Used for Pavement Surface Repairs (SHRP M/UFR-91-505). Volume 5: Partial-Depth Spall Repair (SHRP-H-356). Washington. Smith. Pozsgay. R. 1999.TECHNOLOGIES HOME PRINT BOOKMARKS 354)..D. 1983. Northcott. L. Long-Term Monitoring of SHRP H-106 Pavement Maintenance Materials Test Sites.. Rigid Pavement Design for Airports. Long-Term Monitoring of SHRP SPS-4 Pavement Maintenance Materials Test Sites. Mildenhall. D. Volume 4: Joint Seal Repair (SHRP-H-355). PCC Joint Reseal Experiment Final Report. (no date). Federal Highway Administration. Evans. National Research Council. D.A. 112 .R. Smith. Air Force Manual 88-6. and A. SPS-4 Supplemental Joint Seal Experiment Final Report. Department of Transportation." Transportation Research Record 1392. 1993.C.. K.D. Washington. Washington. et al. Chapter 7–Standard Practices for Sealing Joints and Cracks in Airfield Pavements.L. Volume I: Summary of Material Performance and Experimental Plans (SHRP M/UFR-91-504). K. Pozsgay. D.A. Federal Highway Administration.C. D.L. Steffes. L. K. "Innovative Leak Test for Pavement Joint Seals. M.F.. H. Innovative Materials and Equipment for Pavement Surface Repairs. 1999.C.D.S.S. Romine.C. and A.L. Strategic Highway Research Program (SHRP). Strategic Highway Research Program (SHRP). and G. Washington. 1991. Romine. United States Air Force (USAF). M.R. A Manual for Maintenance and Repair of Concrete Roads. National Research Council. Cement and Concrete Association. Smith.
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