水泥改性冷再生沥青混合料设计与耐久性试验

Design and Durability Test of Cement Cold Reclaimed Asphalt Mixture

分别以3种水泥掺量(3%、4%、5%)和4种旧沥青混合料(RAP)掺量(0%、30%、40%、50%)制备水泥改性冷再生沥青混合料,并将其应用于路面基层。首先,通过击实试验进行混合料配合比设计;然后,通过7 d无侧限抗压强度试验确定混合料的最佳水泥掺量和最佳RAP掺量;最后,采用干湿循环试验和冻融循环试验评价混合料的耐久性能。试验结果表明:水泥改性冷再生沥青混合料的最佳水泥用量为3%,最佳RAP掺量为40%;RAP掺量为40%时,混合料的干湿循环无侧限抗压强度达到最大值,RAP的掺加有效提升了混合料的水稳定性,并且RAP掺量越大,提升效果越明显;水泥有助于混合料抗冻性能的提升,且水泥掺量越大,对于混合料抗冻性能的改善越明显。

The cement modified cold reclaimed asphalt mixture is prepared respectively with three kinds of cement contents(3%,4%and 5%)and four kinds of old asphalt mixtures(0%,30%,40%and 50%),which are applied for the pavement base.Firstly,the mix proportion of mixture is designed through the compaction test.Then,the optimal cement content and the optimal RAP content of the mixture are determined through 7 d unconfined compressive strength test.Finally,the durability performance of the mixture is evaluated by the dry-wet cycle test,and the freeze-thaw cycle test.The test results show that the best cement content of cement modified cold reclaimed asphalt mixture is 3%,and its best RAP content is 40%.When the RAP content is 40%,the dry-wet cycle unconfined compressive strength of the mixture reaches the maximum.The addition of RAP effectively improves the water stability of the mixture.And the higher the RAP content is,the more obvious the effect is.The cement helps to improve the frost resistance of the mixture,and the higher the cement content is,the more obvious the frost resistance of the mixture is.