基于多物理场间接拉伸试验的多孔沥青混凝土水稳定性

Water Stability of Porous Asphalt Concrete Based on Multi-physics Indirect Tensile Test

由于多孔沥青混凝土(PAC)的大孔隙结构和应用环境,目前评价水稳定性能的试验方法和指标较为单一。通过自行研发的多物理场环境箱模拟了不同的降雨阶段,并采用间接拉伸强度试验和间接拉伸疲劳试验评价和研究了PAC的水稳定性能及其破坏过程。与传统水稳定性试验方法相比,采用多物理场间接拉伸评价饱和状态下PAC的水稳定性能具有更好的合理性。在此基础上,进一步采用高温浸水和冻融循环作用加速水损害,发现随着高温浸水时间的增长和冻融循环次数的增加,PAC的水稳定性不断降低,特别是当冻融循环次数达到6次或者高温浸水时间达到6 d时,PAC的水稳定性能显著降低,因此冻融循环次数达到6次或者高温浸水时间达到6 d可作为评价PAC长期水损害的试验条件。此外,本研究基于强度和间接拉伸回弹模量提出了水稳定性能损伤变量,发现损伤变量与剩余疲劳寿命之间具有较好的相关性,因此该损伤变量可用于评价和预测PAC的水稳定性。

Due to the macropore structure and application environment of porous asphalt concrete(PAC),the current experimental methods and indicators for evaluating water stability performance are relatively single.The different rainfall stages were simulated by using self-developed multi-physics field environmental chamber.The indirect tensile strength test and indirect tensile fatigue test were used to evaluate and study the water stability performance and damage process of PAC.Compared with traditional water stability experimental method,it is more reasonable to evaluate the water stability performance of PAC in saturated condition by using multi-physics field indirect tensile test.On this basis,the high temperature immersion and freezing-thawing cycles were further used to accelerate the water damage.With the growth of high temperature immersion time and the increase of freezing-thawing cycles,the water stability of PAC decreases continuously,especially when the number of freezing-thawing cycles reaches 6 times or the high temperature immersion time reaches 6 d.The water stability of PAC can be reduced significantly.Therefore,6 times freezing-thawing cycles or 6 d high temperature immersion time can be used as test conditions to evaluate long-term water damage for PAC.Furthermore,damage variables of water stability performance were proposed based on strength and indirect tensile rebound modulus.The good correlation was found between damage variables and remaining fatigue life.As a result,the damage variables can be used to evaluate and predict the water stability of PAC.