Investigation of mechanical properties of hot mix asphalts prepared with different elastomer modified bitumens

The bituminous pavement layers used in the flexible pavement are the top layer directly exposed to the effects of traffic and the environment, and therefore must be very robust in terms of mechanical properties. To ensure that hot mix bituminous layers can withstand increased traffic loads and do not deform, the binder commonly used in the mix, bitumen, is modified with the polymer additive styrene-butadiene-styrene (SBS). Due to the high demand for SBS, it is difficult to supply when needed, so the use of alternative additives is on the agenda. For this reason, elastomers 701 and 611, which are alternatives to SBS elastomers, were used in the thesis study. Modified bitumen was prepared by adding SBS, 611 and 701 elastomers to the binder at three different rates. Using these modified bitumens, 11 different bituminous hot mix samples were prepared and the mechanical properties of the asphalt mixtures were investigated. Marshall stability and yield, resistance to moisture damage, indirect tensile stiffness modulus, indirect tensile fatigue, and half circle tests were performed on the prepared asphalt mixture samples. The results show that all three additives increase Marshall stability, resistance to moisture damage, stiffness, and fatigue strength compared to the binder alone. When evaluating the results of elastic-plastic fracture mechanics performed on semicircular specimens at 25°C, it was determined that the resistance of the compounds to cracking generally increases with the use of elastomer. As a result of all these mechanical tests, it was found that the most effective elastomer is 611.