The objective of this study is to evaluate the mechanical performance of asphalt mixture composed of coarse aggregates with different flatness and elongation and different contents of flat and elongated particles. Three types of coarse basalt including particles with different ratios of the length to the minimum thickness or width (2.5:1 and 2:1) and flat and elongated (F&E) aggregates were manually picked to prepare asphalt mixture specimens with all those three types of four contents (0%, original, 30%, and 40%) were investigated to evaluate the effects of particles shape on the performance of asphalt concrete (AC) mixtures. Laboratory tests including two-dimensional image analysis, rutting resistance tests, uniaxial compressive tests and compressive resilience modulus tests were conducted to evaluate the state of stone-on-stone contact, mechanical properties, durability and structure stability of AC, respectively. The test results indicate that were significant factors for formation of aggregate skeleton, strength of mixture structure. The functionality, rutting resistance, long-term durability, and skeleton stability decrease with the increase of the flatness and elongation of aggregates and their content since the flatness and elongation of aggregates in asphalt mixtures have a tendency to breakdown. Compared with the contents of F&E, response surface analysis (RSA) showed that the mechanical properties of AC are positively correlated with flatness and elongation of aggregate regardless of the E&F content, and the sensitivity decreases with the decrease of flatness and elongation. Therefore, the stricter requirement for flatness and elongation of aggregates should be met for more asphalt mixtures than the one F&E content of asphalt mixture.

CICTP