细级配沥青混合料的抗裂指标研究

Research on Crack Resistance Performance of Fine Graded Asphalt Mixture

摘要:

裂缝会对沥青路面的正常使用造成极为严重的影响，深入探究沥青材料的微观断裂机理，对于提升路面使用寿命具有关键作用。为此，采用半圆弯曲试验，获取不同试验条件下试件的荷载-位移数据，并据此计算出试件的强度、断裂能、抗裂指数等各类断裂指标，进而研究沥青砂浆在不同温度下的抗裂特性；同时，通过系统分析沥青种类、沥青膜厚度、试验温度、加载速率等因素对沥青砂浆力学特性，尤其是抗裂性能的影响，对沥青砂浆试件开展定量与定性相结合的对比分析研究。结果表明：沥青砂浆的断裂能随着加载速率的增大而减小；SBS改性沥青砂浆的断裂能优于基质沥青砂浆；沥青膜厚度为10 μm时的断裂能优于沥青膜厚度为9 μm时；10 ℃时的断裂能通常优于 -5 ℃时，且分别呈现柔性、脆性断裂及不同荷载-位移曲线。

Abstract:

Cracks have a significant impact on the normal use of asphalt pavements. The microscopic fracture mechanism of asphalt materials is further explored, which has a keying action in improving the service life of pavements. Therefore, the load-displacement data of specimens under different test conditions are obtained through the use of a semi-circular bending experiment, and according to this, various fracture indicators such as the strength, fracture energy and fracture indexes of the specimens are calculated so as to study the crack resistance of asphalt mortar at different temperatures. At the same time, by systematically analyzing the influence of factors such as asphalt type, asphalt film thickness, test temperature and loading rate on the mechanical properties of asphalt mortar, especially its crack resistance performance, a comparative analysis and study combining quantitative and qualitative methods are carried out on the asphalt mortar specimens. The results show that the fracture energy of asphalt mortar decreases with the increase of loading rate. The fracture energy of SBS modified asphalt mortar is superior to that of matrix asphalt mortar. The fracture energy when the asphalt film thickness is 10μm is better than that when the asphalt film thickness is 9μm. And the fracture energy at 10℃ is usually better than that at -5℃. The flexible fracture, brittle fracture and different load-displacement curves are presented respectively.