低RAP掺量沥青混合料冻融性能试验

Freezing-thawing experiments for asphalt mixtures with low RAP contents

针对低掺量RAP热拌沥青混合料的抗冻融性能存在的一些问题,采用不同RAP掺量和不同级配类型的沥青混合料进行冻融劈裂试验.利用多元线性回归建立影响因素与强度比的关系,采用因子分析法找出主要的影响因子,并利用超景深显微镜及电镜分析沥青混合料的微观形貌.结果表明:AC-10材料的冻融劈裂强度比优于AC-13;随着RAP掺量的增加,冻融劈裂强度比随之下降;粒径1.18 mm以下的细集料与沥青的老化程度是影响冻融劈裂强度的关键因素.

In order to solve some existing problems of anti-freezing-thawing performances of hot-mixed asphalt mixtures with low RAP contents,freezing-thawing splitting experiments were carried out for the asphalt mixtures with different RAP contents and different grading types.The relationship between influencing factors and strength ratio was established with the multivariate linear regression,and main influencing factors were discovered with the factor analysis method.In addition,the microstructure of asphalt mixture was analyzed with the microscope with super field depth and scanning electron microscope(SEM).The results show that the freezing-thawing splitting strength ratio of AC-10 is better than that of AC-13.With the increasing RAP contents,the freezing-thawing splitting strength ratio decreases.The fine aggregates with grain sizes below 1.18 mm and the aging degree of asphalt are key factors affecting the freezing-thawing splitting strength.