Effects of Coarse Aggregate Form, Angularity, and Surface Texture on Concrete Mechanical Performance

Abstract

While aggregates are predominantly responsible for concrete properties, influences of coarse-aggregate shapes (form and angularity) and surface texture on concrete mechanical performance are not well understood. This paper designed and tested a series of concrete specimens manufactured with coarse aggregates varied in form, angularities, and surface textures, which enabled us to systematically analyze the influence of these features on the overall mechanical performance of concrete materials. The coarse aggregates form, angularity, and surface texture were quantified by the flat and elongated ratio (FER), angularity index (AI), and surface roughness (SR), respectively. Test results indicated that the splitting tensile strength and compressive strength of concrete were enhanced with an increased SR but dropped significantly with an increase in the FER or AI. Both of the elastic modulus and Poisson’s ratio decreased slightly with the increase in FER or AI, yet increased with an increase in SR. A mesomechanical model was introduced to estimate the performance of materials with results validated by those obtained from the test. The effects of the random FER, AI, and SR on the variability of concrete mechanical properties were further simulated in-depth. All research results confirmed that random FER, AI, and SR of coarse aggregates have considerable effects on the variability of concrete mechanical properties.