无机微粉填料对沥青胶浆疲劳性能影响规律分析

Analysis on fatigue performance of asphalt mortar with inorganic micro-powder filler

摘要:

为了探究无机微粉填料在沥青胶浆中的疲劳性能影响规律,以3类9种常用无机微粉颗粒作为添加矿料,从无机微粉填料颗粒形貌特征、填料类型和颗粒粒径出发,通过扫描电镜（SEM）对微粉颗粒的形貌特征进行表征,再通过动态剪切流变仪（DSR）时间扫描试验分析不同种类微粉填料对沥青胶浆的疲劳性能的影响规律,然后采用N_f50和N_DER两种指标对沥青胶浆疲劳寿命进行比对分析。 结果表明:扫描电镜下消石灰微粉颗粒表现出较多的表面孔隙和复杂表面纹理,动态剪切流变试验下随着无机微粉颗粒粒径的减小,沥青胶浆的疲劳性能有较大改善；同一颗粒粒径下,由于形貌特征和化学组成的差异使消石灰和水泥表现出优于石灰岩的疲劳性能；N_DER与N_f50相比,疲劳寿命意义清晰、数值易确定,且所获得疲劳寿命加载次数均较小,用于沥青路面结构设计和材料选择安全性高,推荐采用N_DER对胶浆疲劳寿命进行分析。

Abstract:

In order to explore the influence of inorganic micro-powder fillers on the fatigue performance of asphalt mortar, nine kinds of commonly used inorganic micro-powder particles in three types were used as additive mineral materials, and the morphology characteristics, filler types, and particle sizes of the micro-powder particles were investigated. The morphology characteristics of the micro-powder particles were characterized by SEM, the influence of different kinds of micro-powder fillers on the fatigue properties of asphalt mortar was studied by dynamic shear rheometer (DSR), and the fatigue life of asphalt mortar was compared and analyzed by indexes N_f50 and N_DER. Results show that under SEM, the hydrated lime particles had more surface pores and complex surface texture, and the fatigue performance of the asphalt mortar was greatly improved with the decrease in the particle size of the inorganic micro-powder filler under dynamic shear rheological test. With the same particle size, due to the special morphology characteristics and chemical compositions, the fatigue performances of hydrated lime and cement were better than that of limestone. Compared with N_f50, the fatigue life meaning of N_DER was clearer, the numerical value was easier to determine, and the obtained fatigue life loading times were smaller. The use of N_DER in asphalt pavement structure design and material selection is safer, so it is recommended to adopt N_DER for the analysis of the fatigue life of mortar.