Gradation of limestone-aggregate-based porous asphalt concrete under dynamic crushing test: composition, fragmentation and stability
Gradation of limestone-aggregate-based porous asphalt concrete under dynamic crushing test: composition, fragmentation and stability
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DOI：
10.1016/j.conbuildmat.2022.126532
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发表时间：
2022-01-31
影响因子：
7.4
通讯作者：
Chen, Zongwu
中科院分区：
文献类型：
--
作者：
Cai, Jun;Song, Chen;Chen, Zongwu
多孔沥青混凝土（PAC）中对玄武岩等具有优良力学性能的集料的需求量很大。而在高品质玄武岩不足的地区，具有可接受性能的石灰石骨料被认为是一种潜在的替代品。针对石灰石集料PAC级配的长期性能和反复应力作用下的稳定性研究较少的情况，对石灰石集料PAC级配的组成、破碎性和稳定性进行了分析。首先，采用动态压碎试验（DCT）模拟PAC级配的应力特性。其次，采用单一集料级配（SSRA）和PAC级配确定并验证了试验条件。第三，研究了形成的构造体系的组成、分布特征及稳定性。最后，采用更多的PAC分级来进一步验证结论。结果表明，通过一个循环试验，试验样品已达到相对稳定性，受试验温度的影响不显著。4.75mm粒径的骨料对结构体系稳定性的影响最大，而2.36mm和9.5mm粒径的骨料对结构体系稳定性的改善作用也很大。与SSRA不同，SSRA受其自身客观破碎特性的影响，并导致新形成体系的较大空隙率，PAC级配中的集料受客观破碎特性以及结构骨架的影响。新形成的PAC级配体系的集料粒径分布介于AC级配和PAC级配之间，更接近AC级配。此外，这些形成的系统已被证明具有更好的稳定性比类似的空气空隙率的控制样品。
Aggregate with excellent mechanical properties, like basalt, is always in great demand in porous asphalt concrete (PAC). While in areas where high-quality basalt is insufficient, limestone aggregate with acceptable performance is considered as a potential alternative. This paper analyzed the composition, fragmentation and stability of PAC gradation based on limestone aggregate since its long-term performance and stability under repeated stresses still haven't been studied. Firstly, dynamic crushing test (DCT) was adopted to simulate the stress characteristics of PAC gradation. Secondly, single size range of aggregate (SSRA) and PAC gradation were used to determine and verify the test conditions. Thirdly, composition, distribution characteristics and stability of formed structural systems were studied. Lastly, more PAC gradations were adopted to further verify the conclusions. Results showing the test samples have reached relative stability by one-cycle test, were not significantly influenced by test temperature. In DCTs, aggregate of 4.75 mm had a critical effect on structural systems stability, while aggregates of 2.36 mm and 9.5 mm also played important roles in improving systems' stability. Unlike SSRA, which was influenced by its own objective crushing characteristics and contributed to larger air void ratios of newlyformed-systems, aggregates in PAC gradations were affected by objective crushing characteristics as well as structural skeletons. Aggregate particle size distribution of newly-formed-systems of PAC gradations was between those of AC and PAC gradations, more closed to that of AC gradation. Besides, those formed systems have been proved to have better stabilities than control samples of similar air void ratios.