Study On Aggregate Angularity Influence On The Performance Of Asphalt Mixture

Because China don't have enough research on aggregate Angularity and Chinese standard haven't evaluation method of coarse aggregate angularity. To provide solving these problems,the paper analyzes the effect of the angularity of aggregate on asphalt mixture by a large number of laboratory tests.This study analysis the evaluate methods and indicators of coarse aggregate angularity at home and abroad, and analysis the applicability of each method. According the present situation of china, used digital image processing(DIP) to evaluate the angularity of coarse aggregate, In order to compare aggregate angularity on the performance of asphalt mixture, this study will be 4.75mm～16mm of coarse aggregate in the Los Angeles abrasion instrument wear different times, in order to form four kinds of different coarse angularity aggregates, using AC-16 asphalt mixture and four kinds of coarse aggregate which has different angularity to evaluate the effect of coarse aggregate angularity on the asphalt mixture performance such as volume index water stability, high temperature stability and low temperature performance.This paper studied the fine aggregate angularity by flow times which is recommended by Chinese standardized methods, using AC-13F asphalt mixture and four kinds of fine aggregate to evaluate the effect of fine aggregate angularity on asphalt mixture performance.Through lab tests it is shown that the aggregate angularity have different effect on asphalt mixture performance. With the increase of coarse aggregate angularity, asphalt mixture's VMA increase, the VV and VFA drops, dynamic stability increase, the water stability of mixture decreases and low temperature performance decreases and then increases; With the fine aggregate angularity increases, asphalt mixtures VMA increase, the VV and VFA drops, dynamic stability increase,the water stability of the mixture decreases and then increases.