ABSTRACT
A direct-cast composite modified asphalt mixture was prepared by direct-cast environmental modifier, SBS and mineral materials and applied to ultra-thin overlay asphalt mixture. The effects of different dosage and type of direct casting modifier on high temperature performance, water stability and low temperature crack resistance of the mixture were studied. The results show that compared with SBS modified asphalt, when the SP-2 direct-input modifier content is 0.6 % of the mineral mass, the high-temperature stability increases by 111 %, and the freeze-thaw splitting strength ratio increases by 16 %. However, the low-temperature crack resistance decreases to a certain extent, and the optimal content is less than 0.4 % of the mineral mass. Through the test section paving verification, direct cast modified asphalt mixture has more convenient construction, more excellent road performance, and its performance meets the requirements of the current specification.
