Mechanical properties and gas permeability of coral aggregate concrete incorporating supplementary cementitious materials

Abstract

The permeability of CAC greatly limits the long-term performance of CAC structures which is a new solution to the shortage of construction materials on the islands and reefs. In this paper, to improve the permeability of CAC, supplementary cementitious materials (SCMs) were added into CAC, and the effects of SCMs on compressive strength, water absorption, and gas permeability of CAC were studied. The water permeability of CAC was calculated from the gas permeability and slip factor. Microtopography, phase composition, and thermogravimetric loss were tested to investigate the effects of SCMs on the permeability of CAC at the micro-level. The absolute porosity of CAC was calculated based on the content of bound water in the TG data to evaluate the improvement of SCMs on the permeability of CAC. The results showed that there was a significant negative correlation between water absorption and compressive strength. The gas permeability of CAC incorporating 20% BFS and 10% MK was reduced by 61.2% compared with that of CAC without SCMs. The CAC improved by SCMs obtained in this paper has good future application prospects in remote island environments.