Influence of temperature and rest period on the fatigue response of bituminous mixtures

Abstract

All the bituminous mixtures are designed to withstand rutting and newlinefatigue damage due to repeated load application. The fatigue distress in the newlinematerial is relatively complex to quantify as the healing during the rest period newlineplays a critical factor. When the bituminous material is subjected to loading newlinefollowed by a rest period, one can see a relaxation of stresses followed by a newlinepossibility of healing. As the temperature reduces, and as the material newlinebecomes more elastic, the beneficial effects due to stress relaxation might newlinereduce during rest periods. In addition, simulation of real-life multi-axle newlinetrucks through a carefully designed test program can throw more light on the newlineexpected behavior, and this investigation reported that aspect. One concern in newlinesuch fatigue testing is the role played by the magnitude of strain. A newlineconsiderably large strain can shorten the testing time, however, it is not clear newlinewhether the damage accumulation seen for fatigue testing can be simulated in newlinesuch large strain experiments. However, it is also known that the modifier in newlinethe binder gets activated and resists the load applied only under large applied newlinedeformation. With these constraints, this thesis reports the experimental newlineinvestigation conducted on various bituminous mixtures produced using newlinemodified and unmodified binders to characterize the fatigue damage of the newlinebituminous mixture. The influence of the rest period between two loading newlinecycles at different temperatures is also quantified. newlineThis investigation reports the fatigue response of bituminous newlinemixtures carried out using a four-point bending test. In this study, four-point newlinebeam bending tests were conducted on bituminous mixture samples related to newlinebituminous concrete (BC) grade II as per MORTH specification. For this newlinepurpose, a typical bituminous mixture used in Indian highways was fabricated newlinewith unmodified binder and modified binder. newline