Bituminous mixes prepared using recycled coarse aggregate exhibit inferior characteristics compared to a control mix using natural stone aggregate. This is mostly due to the presence of loose cement mortar in the recycled aggregate. The study reported in this paper evaluated the performances of recycled aggregate mixes using different polymers, including centrifuged latex polymer, crumb rubber powder and polypropylene fibre. The performance of these polymer-reinforced mixes was then evaluated using a retained Marshall stability test, tensile strength ratio test, four-point bending test and wheel-tracking test. The results showed that all polymers improved the performance of the recycled aggregate mixes, making them better than the control mix. Moreover, cost analysis revealed that unmodified, centrifuged latex polymer and crumb rubber powder are more cost-effective than the control mix, whereas the polypropylene fibre mix was found to be expensive in terms of initial cost. Life-cycle cost analysis, however, showed that the fibre mix was also economical over the long run compared to the control mix. Overall, all polymer-modified mixes using recycled coarse aggregate showed better performance and were more cost-effective that natural stone aggregate mixes, meaning they are a viable alternative for road construction.

中文翻译：

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使用再生粗骨料的聚合物增强沥青混合物的性能

与使用天然石材骨料的对照混合物相比，使用再生粗骨料制备的沥青混合物表现出较差的特性。这主要是由于再生骨料中存在松散的水泥砂浆。本文报道的研究评估了使用不同聚合物的再生骨料混合物的性能，这些聚合物包括离心乳胶聚合物，粒状橡胶粉和聚丙烯纤维。然后使用保留的马歇尔稳定性测试，拉伸强度比测试，四点弯曲测试和车轮跟踪测试对这些聚合物增强混合物的性能进行评估。结果表明，所有聚合物均改善了回收骨料混合物的性能，使其优于对照混合物。此外，成本分析显示，未经修改，离心乳胶聚合物和碎橡胶粉比对照混合物更具成本效益，而发现聚丙烯纤维混合物的初始成本较高。但是，生命周期成本分析表明，与对照混合物相比，从长远来看，纤维混合物也是经济的。总体而言，所有使用再生粗骨料的聚合物改性混合物均比天然石骨料混合物表现出更好的性能和更具成本效益，这意味着它们是道路施工的可行替代品。