Test and evaluation for effects of aggregates fragmentation on performance of lightweight asphalt concrete

Effects of aggregates fragmentation on performance of lightweight asphalt concrete are studied in this paper. The Marshall mixture design method was used to determine the optimum asphalt content of lightweight SMA-13 (LSMA-13). Gyratory compaction test was taken to simulate aggregates crushing. British Pendulum Tester, sand patch method, rutting test, indirect tensile strength test, freeze-thaw splitting test and soaked Marshall stability test were adopted to study the effects of aggregates fragmentation on friction, high temperature stability, low temperature crack resistance and moisture susceptibility of LSMA-13, respectively. The results show that lightweight aggregates have little effects on the fragmentation of basalt aggregates whose particle size is larger than that of lightweight aggregates, but can prevent the basalt aggregates whose particle size is smaller than that of lightweight aggregates from breaking. The number of gyrations and the replacement percentage of lightweight aggregates have negative effects on the aggregates fragmentation index (AFI) of LSMA-13. LSMA-13 have good skid resistance and the effects of aggregates fragmentation on friction of lightweight asphalt concrete are not obvious. The larger the AFI value is, the smaller the dynamic stability (DS) is. And when AFI is larger than 6%, DS of LSMA-13 is smaller than DS criteria (3000 mm−1). 6% can be used as the AFI criterion of LSMA-13 for pavement engineering. Moreover, the effects of aggregates fragmentation on low temperature crack resistance of LSMA-13 are not obvious. The replacement percentage of lightweight aggregates of LSMA-13 has negative effect on its low temperature crack resistance. And the aggregates fragmentation of LSMA-13 has positive effect on its moisture susceptibility. LSMA-13 are not recommended to be applied in cold regions engineering, but are recommended to be applied in rainy regions engineering.