动水冲刷对AC-20沥青混合料性能影响评判

An evaluation on the effect of dynamic water scouring action to the performance of AC-20 asphalt mixture

为研究动水冲刷作用对不同空隙率沥青混合料性能的影响规律,在实验室采用旋转压实成型空隙率为4%,6%,8%和10%的AC-20沥青混合料试件,利用自研的新型动水冲刷装置进行了动水冲刷试验,对冲刷前、后指标(渗水系数、抗压强度、劈裂强度及冲刷量等)的变化进行了比较。研究结果表明:动水冲刷对沥青混合料性能存在不利影响,不同空隙率的影响程度不同。由冲刷前、后抗压强度和劈裂强度的变化可知,AC-20混合料最不利空隙率为8%;冲刷后渗水系数有小幅增加,冲刷量随着空隙率的增加而增加,但其增长率逐渐趋于平缓。提出了残留强度比的抗冲刷性能评价标准。

In order to study the influence law of dynamic water scouring action on the performance of asphalt mixture with different porosities,AC-20 mixture samples with porosities of 4% ,6% ,8% and 10% molded by SGC method are tested by self-developed test device. Based on the test, the mixture parameters such as permeability coefficient, compressive strength, indirect strength and mass are comparatively analyzed.The results show that dynamic water scouring has adverse impact on the performances of the asphalt mixture and the degree changes with the porosity. It can be inferred that the most ad- verse porosity is 8% from the change of compressive strength and splitting strength before and after the above test.The permeability coefficient increases modestly, and the erosion quantity increases with porosity but the growth rate tends to flatten.As a reference to the standard of water stability evaluation in the construction technological specification of the asphalt pavement, the evaluation index of anti-erosion performance of tensile strength ratio is put forward.