Effect of aggregate shape on the properties of asphaltic concrete AC14

Abstract

The objective of this study is to evaluate the effects of aggregate shape on volumetric properties of asphaltic concrete mixtures. The aggregate gradation of AC14 was prepared using granite aggregates crushed via compression and impact crushers. In this study, compression crusher was used to produce aggregates with flaky and elongated shape while the impact crusher was used to produce aggregates with a cubical shape. Modified bitumen, Styrene-Butadiene-Styrene (SBS) was used in preparing the specimens. The stability, density, voids in total mix, voids filled with bitumen, and voids in mineral aggregate of asphalt mixture specimens was investigated. In addition, the resilient modulus test with temperature of 25°C and stiffness modulus test with temperature of 40°C was carried out using the Universal Testing Machine in accordance with ASTM D4123 standard. The test results showed that the volumetric properties improved when cubical aggregate was introduced to the asphalt mixture. Moreover, the incorporation of geometrically cubical aggregates in asphalt mixture causes an increase in resilient and stiffness modulus compared to asphalt mixture prepared with irregularly aggregates