RAP掺量对再生沥青混合料的性能影响研究

Influence Evaluation of RAP contents on properties of Asphalt Mixtures

高RAP掺量再生沥青混合料在我国沥青路面养护中得到越来越多的应用,厂拌热再生中RAP掺量可达到30%～50%,就地热再生中RAP掺量更是达到80%以上。在室内设计RAP掺量为0%、30%、50%、85%和100%的5种AC-13级配沥青混合料,依托UTM试验机分别采用动态蠕变试验、半圆弯曲试验和多重冻融劈裂试验对混合料的高温抗车辙性能、低温抗裂性能和抗水损害性能进行评价,结果表明:相比新沥青,RAP沥青胶结料高温性能增强而低温性能衰退;随着RAP掺量的增加,再生沥青混合料的高温抗车辙性能增强,低温抗裂性能和抗水损害性能降低,100%RAP混合料受到级配细化的影响,抗车辙性能不及新沥青混合料;多重冻融劈裂相比单次冻融劈裂能够更好地评价再生混合料的水稳定性。

Asphalt mixture with high RAP content are more and more utilized of asphalt pavement maintenance. RAP content could be up to 30% ～50 % in hot in-plant recycling and more than 80% in hot in-place recycling. In order to evaluate the influence of RAP content on performance of asphalt mixtures,AC-13 gradation asphalt mixtures with 0% 、30% 、50% 、85% and 100%RAP contents were designed and produced in lab. The flow number test, semi-circular bending test, and multiple freeze-thaw splitting test were conducted in UTM-25 to evaluate mixture properties s. It is found that compared with fresh asphalt, RAP binder's high-temperature property improves while its low-temperature property declines. With the increase of RAP content, the asphalt mixture's rutting resistance property improves, but the resistance abilities of low-temperature cracking and moisture damage decline. Because of the reduce of coarse aggregates, the 100 % RAP mixture has lower rutting resistance than fresh mixture. The multiple freeze-thaw splitting test could be better measure the moisture susceptibility of high RAP mixtures than single cycle freeze-thaw splitting test.