Durability and microstructure of coral sand concrete incorporating supplementary cementitious materials

This paper was investigated the durability performances of coral sand concrete (CSC) production by using porous coral sand aggregate and supplementary cementitious materials (SCMs) compared to river sand concrete (RSC). The durability properties of CSC were evaluated in terms of chloride penetration, water absorption, drying shrinkage, accelerated carbonation, and sulfate drying-wetting cycle. The results indicated that the CSC exhibited higher drying shrinkage, capillary water absorption, carbonation depths, and a slightly lower later compressive strength compared with RSC. However, porous coral aggregate provided a more rapid early age strength, better resistance to chloride ion penetration, and sulfate drying-wetting cycle than the RSC due to its internal curing. Additionally, the combinations of internal curing and pozzolanic reaction contributed to the microstructure improvement of CSC, which conformed good durability properties of CSC containing SCMs. Moreover, the ecological evaluation demonstrated that the CSC incorporation of SCMs resulted in a significant reduction of CO2 emission.