Particle size effects on breakage of ACT aggregates under physical and environmental loadings

Abstract

Aggregates manufactured from fine-grained thermal waste residues using accelerated carbonation technology (ACT) represent a potential sustainable alternative to natural aggregates. However, for these manufactured products to compete with virgin stone in geotechnical applications, their durability under mechanical and environmental loadings must be assessed. This paper describes particle breakage that occurs for different grain sizes (entire sample, 5mm-2.5mm, and 2.5mm-1.25 mm) of a cement kiln dust accelerated carbonated manufactured aggregate after undergoing triaxial compression, triaxial shear and freeze/thaw (f/t) testing. It is shown that the particle breakage of the aggregate is dominated by the larger (5mm-2.5mm) size fraction of the sample under all loading conditions. Particle breakage results from f/t testing showed that the 5mm-2.5mm size corresponded to similar or slightly less particle breakage than that under triaxial shear, while the particle breakage of the 2.5mm-1.25mm aggregate after 20 cycles of freeze-thaw was relatively small. The performance of the carbonated aggregate in terms of relative breakage was similar or slightly better than natural calcareous sand results in the literature.