RAP对乳化沥青冷再生混合料级配设计的影响研究

冷再生混合料与传统的热拌沥青混合料(HMA)在级配设计中的不同是由于RAP的掺入对混合料的影响,特别是RAP在回收过程中的高变异性对混合料级配的影响。通过对比分析采用RAP的原样筛分和抽提筛分级配曲线添加一定比例新集料进行级配设计,然后采用贝雷法的级配设计理论,基于粗集料骨架嵌挤,细集料逐级填充的设计思路进行级配检验,在满足CA]、FAc]、FAf]3个参数的要求后,反算贝雷法设计密度,分析了RAP的掺入对贝雷法设计密度及3参数的影响,同时依据混合料的低温劈裂强度、冻融劈裂强度、动稳定度和间接拉伸疲劳寿命来评价两种级配混合料的性能,最后给出合理的贝雷法设计密度及应按照RAP的抽提筛分级配曲线来调整混合料的合成级配。

Influence of RAP on the Gradation Design of Emulsified Asphalt Cold Regeneration

In the gradation design,one of the differences for cold recycled mixture and the traditional hot mix asphalt mixture(HMA) is due to the influence on the mixture mixed with RAP, especially the impact on mixture gradation for RAP high variability in the recycling process. In this article, adopting the RAP same screening and extraction screening grading curve to add a certain proportion new aggregate through comparative analysis for gradation design and then using the gradation design theory of bailey method to procing a gradation test which is based on the embedded squeeze of coarse aggregate skeleton and the design ideas of the fine aggregate stage filling. When it meets the requirements of CA], FAc], FAf] three parameters,then back to calculate the design density of bailey method and analyze the influence on the design density of bailey method and three parameters with the RAP mixed. At the same time, on the basis of the mixture of low-temperature splitting strength, freeze-thaw splitting strength , dynamic stability and ITS fatigue to evaluate road performance of the two gradation mixture, finally providing the reasonable design density value of bailey method and should be in accordance with the RAP extraction screening to adjust the mixture synthesis gradation.