Effect of Autoclaved Aggregate Structure on Strength of Concrete

Abstract

This paper focuses on studying the physical and mechanical performance of propylene oxide sludge aggregates having no shell (POSA-0), single storey shell (POSA-1) and gradient shell (POSA-2) prepared by hydrothermal synthesis and autoclave curing process. The effect of the aggregate structure on strength of their concrete has been examined and discussed in case of a fixed water cement ratio. The results show that all the autoclaved propylene oxide sludge aggregate (POSA) were light-weight and high-strength regardless of the aggregate structure and all three structured POSA have no wall effect with the cement mortar. Aggregate structure has little influence on the physical and mechanical performance of POSA and splitting tension strength of POSA concrete, however, it plays important role in dictating the compressive strength of concrete because of their different extent of influence on the improvement of interface and relieving the stress concentration. 28d compressive strength of the concrete with the POSA-2 as coarse aggregate can reach 82 MPa, which is 13.9%, 2.5% and 10.8% higher than that of the concrete with POSA-0 as coarse aggregate, the concrete with POSA-1 as coarse aggregate and common concrete, respectively. 28d splitting tension strength of common concrete can reach 7.76 MPa, which is higher 22.6%, 16.3%, 15.8% than that of concrete with POSA-0 as coarse aggregate, concrete with POSA-1 as coarse aggregate and concrete with POSA-2 as coarse aggregate, respectively.