Influence of size and surface condition of distributing-filling coarse aggregate on the properties of aggregate-interlocking concrete

Abstract

The previous researches have proved distributing-filling coarse aggregate (DFCA) process is an efficient approach to improve the performance of concrete. To clarify the technical requirements of adding aggregate for DFCA concrete, the influence of size and surface condition of the added coarse aggregate on the mechanical properties and durability of DFCA concretes are investigated. With a distributing-filling ratio of 15%, the compressive strength of DFCA concretes is 11.6–27.0% higher than the original concrete, while the DFCA with size of 5–10 mm is adverse to the compressive strength. Using coarse aggregate of 20–25 mm as DFCA, the limestone powder as aggregate microfine could further improve the compressive strength of DFCA concrete with a distributing-filling ratio of 20%, while generally, the surface conditions of DFCA have slightly influences on the flexural strength, permeability, drying shrinkage and freezing-thawing resistance of DFCA concrete. The coarse aggregate volume fraction plays a more important role than the surface conditions. The increasing volume fraction of coarse aggregate could reduce the permeability and drying shrinkage, but it significantly degrades the frost resistance of concrete.