The Research On Evaluation Index And Performance Of Aggregate Segregation In Asphalt Pavement

Aggregate segregation is a serious problem in the construction of asphalt pavement. Aggregate segregation leads to some problems, for instance asphalt mixture can not accord with the requirements for gradation and asphalt content in mix design in specifications, and there are certain differences between the indexes, such as density, air voids, stiffness, tensile strength and fatigue life of bituminous mixtures, and design value. This results in accelerated normal pavement distresses such as raveling, cracking, fatigue, rutting and so on.In the last few years, aggregate segregation is paid attention to in many researches. However, the problem that what method and index are chose to evaluate aggregate segregation quantitatively isn't resolved well. Meanwhile, the influence of aggregate segregation of different degree to mechanical properties of asphalt mixture demands prompt solution for the research of aggregate segregation.Through laboratory tests to simulate aggregate segregation of different degree, the parameters of specific surface area, asphalt content and air voids was determined preliminarily as indexes of evaluating aggregate segregation quantitatively.By way of the test research on mechanical properties such as cohesion, inner angular, Marshall Stability, resilient modulus, dynamic stability, Marshall Residual Stability, failure strain under low temperature, etc, based on Strength Formation Mechanism, the influence of aggregate segregation to the performance of asphalt mixture was analyzed, and the rationality of evaluation indexes and grade classification of aggregate segregation was verified, and possible failure modes of pavement caused by segregation of different degree were analyzed.Finally, by using structure reliability theory, according to classification of segregation grade and test results, the reliability of asphalt pavement structure in segregation of different degree was calculated, and the influence of aggregate segregation to designed reliability of asphalt pavement was analyzed.