Diamond grinding is a pavement preservation technique that corrects a variety of surface imperfections on both concrete and asphalt concrete pavements. Most often utilized on concrete pavement, diamond grinding is typically performed in conjunction with other concrete pavement preservation (CPP) techniques such as road slab stabilization, full- and partial-depth repair, dowel bar retrofit, cross stitching longitudinal cracks or joints and joint and crack resealing. Diamond grinding restores rideability by removing surface irregularities caused during construction or through repeated traffic loading over time. The immediate effect of diamond grinding is a significant improvement in the smoothness of a pavement. Another important effect of diamond grinding is the considerable increase in surface macrotexture and consequent improvement in skid resistance, noise reduction and safety. History The industry can be traced back to an event where a single diamond blade mounted on a concrete saw was used to groove concrete pavement in the late 1940s. Since that early tentative step, concrete grinding, grooving and texturing with diamond blades has developed into what is today a multimillion-dollar industry that is practiced worldwide. One of the first uses of diamond grinding of highway pavement was in 1965 on a 19-year-old section of Interstate 10 in California to eliminate excessive faulting. The pavement was ground again in 1984 and in 1997, and it is still carrying heavy traffic today, more than 60 years after it was first constructed. Process Diamond grinding involves removing a thin layer at the surface of hardened PCC using closely spaced diamond saw blades. The level surface is achieved by running the blade assembly at a predetermined level across the pavement surface, which produces saw cut grooves. The uncut concrete between each saw cut breaks off more or less at a constant level above the saw cut grooves, leaving a level surface (at a macroscopic level) with longitudinal texture. The result is a pavement that is smooth, safe, quiet and pleasing to travel. The diamond blades are composed of industrial diamonds and metallurgical powder. When grinding materials contain hard aggregate materials, a diamond blade with a soft bond is needed, which means that the metallurgical powders in the cutting segments of the blade wear fast enough to expose the diamond cutting media at the proper rate for efficient cutting. Conversely, to cut soft aggregates, a diamond blade with a hard bond is recommended. Diamond grinding should not be confused with milling or scarifying.