Fly ash has been recognized as hazardous material causing air, soil and water pollution. Fly ash a 'waste by-product' of electricity generation from power plants (coal-based thermal) has an estimated annual production of approximately two hundred million tons. In-spite of many problems associated (like land requirement for disposal, toxicity to groundwater, handling issues etc.); we have started treating fly ash as a resource material. Present research addresses usage of fly ash in roads & bridges and embankments. In the present study, an attempt has been made to recognize and analyze comprehensively key elements and sub-elements of program implementation of fly ash usage and further to segregate Critical factors (CFs) of usage of fly ash in roads & bridges and embankments. Eight relevant CFs have been recognized for usage of fly ash in roads & bridges; and ten CFs for the usage of fly ash in embankments. Thereafter, Interpretive Structural Modeling (ISM) approach has been applied on these CFs and two models of driver CFs, linkage CFs and driven CFs have been obtained. Appropriate discussions along-with MICMAC analysis in the light of important elements and sub-elements have helped to present managerial implications useful for stakeholders. (C) 2016 Elsevier Ltd. All rights reserved.