Research On Microscopic Mechanical Properties Of Asphalt Mortar

The asphalt mortar is a kind of heterogeneity compound material which is composed together by asphalt and fine aggregates, and its engineering properties are quite complex. To describe its engineering properties correctly, a good outlet is to start from its microscopic structure, analyze its mechanical properties through by experiments and establish the microscopic structure model to simulate its mechanical properties. In such background, this article has done this research, and we hope to establish the microscopic structure model of asphalt mortar which provides an analysis method and tool for microscopic analysis of asphalt mortar.Firstly, this paper carries on mix design of asphalt mortar. Gradation asphalt mortar is to remove the coarse aggregates in median gradation of AC-13 which is recommended in Technical Specification for Constraction of Highway Asphalt Pavements and remain the Proportion of the fine aggregates. It is assumed that the asphalt film thickness of asphalt mortar still maintaines the asphalt film thickness of AC-13 after deducting the coarse aggregates, and the asphalt content of asphalt mortar is calculated by surbtracting asphalt absorbed by coarse aggregates from the asphalt content of AC-13.Then, some researches on the mechanical properties of asphalt mortar have been done. Through uniaxial compression creep experiments we analyze the influence of different aggregate composition and content to high temperature performance of asphalt mortar, and use the Burgers model to simulate the stress-strain curve obtained in creep tests to get four viscoelasticity parameters. We also study the low temperature performance of bituminous mortar by bending test of small beam. Moreover, the paper uses grey entropy method to determine the primary and secondary relation of the influence of aggregate content and asphalt content to the asphalt viscoelasticity parameters and low temperature performance. Finally, we simulate the uniaxial compression test of the asphalt mortar applied by numerical model established by the PFC, and research the influence of microscopic parameters to the virtual experiment results.