Evaluation of the sensitivity of asphalt concrete modulus to binder oxidation with a multiple length scale study
Evaluation of the sensitivity of asphalt concrete modulus to binder oxidation with a multiple length scale study
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DOI：
10.1016/j.conbuildmat.2017.07.067
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发表时间：
2017-10
影响因子：
7.4
通讯作者：
Akshay Gundla;Padmini Gudipudi;B. Underwood
中科院分区：
文献类型：
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作者：
Akshay Gundla;Padmini Gudipudi;B. Underwood
沥青混凝土混合料的性能受沥青胶结料氧化的影响是众所周知的。然而，这两个长度尺度之间的精确关系在很大程度上仍然没有特征。在本研究中，一个多尺度的评价方法是适用于研究和量化的沥青混凝土混合料的力学性能的沥青水泥氧化的敏感性。该研究涉及对未老化和老化沥青水泥（以建立基线特性）、沥青胶浆（以考虑物理化学方面）和细集料基质（FAM -以考虑空隙和集料相互作用效应）的温度和频率扫描实验。多尺度方法将骨料-粘合剂物理化学相互作用的影响与空隙和物理骨料相互作用引起的影响分开。此外，在制备相应的老化胶浆或FAM样品之前，将所有沥青水泥预老化至特定的老化水平。采用交叉模量理论和沥青结合料氧化二级速率动力学方法进行敏感性评价。分析结果表明，胶粘剂的力学性能对粘结剂氧化的敏感性高于FAM。此外，用较软的粘合剂制备的胶粘剂和FAM材料的机械性能比用较高模量的沥青水泥制备的材料对氧化更敏感。最后，发现如果发现实验室老化程序在给定的精度水平下匹配使用中沥青氧化水平的流变性质，则在匹配经受该实验室过程之后测试的沥青混合物的所得模量方面的预期精度将高1.5-3.6倍。
It is well known that the properties of asphalt concrete mixture are affected by the oxidation of asphalt cement. However, the precise relationship between these two length scales remains largely uncharacterized. In the present study, a multiple length scale evaluation approach is applied to study and quantify the sensitivity of the mechanical properties of asphalt concrete mixture to asphalt cement oxidation. The study involves temperature and frequency sweep experiments on unaged and aged asphalt cement (to establish baseline properties), asphalt mastic (to consider physico-chemical aspects), and Fine Aggregate Matrix (FAM – to consider air voids and aggregate interaction effects). The multiscale approach separates effects of aggregate-binder physico-chemical interactions from those caused by air voids and physical aggregate interactions. Also, all asphalt cements were pre-aged to specific aging levels before preparing respective aged mastics or FAM samples. The methodology adopted for assessment of sensitivity was based on the theory of crossover modulus and second order rate kinetics of asphalt binder oxidation. The results from the analysis indicate that the mechanical properties of mastics are more sensitive to binder oxidation than FAM. Also, mechanical properties of mastics and FAM materials prepared with softer binders are more sensitive to oxidation than those with higher modulus asphalt cements. Finally, it is found that if a laboratory aging procedure is found to match the rheological properties of in-service level of asphalt oxidation at a given level of accuracy, then the expected accuracy in matching the resulting modulus of an asphalt mixture tested after being subjected to that laboratory process will be 1.5–3.6 times higher.