MIX PROPORTION DESIGN OF HIGH-STRENGTH SEAWATER CORAL AGGREGATE CONCRETE

Aiming at a high-strength seawater coral aggregate concrete (SCAC),the paper thoroughly examined the effects of several key mix parameters,such as the total cementitious material dosage,the maximum size of coral stone,the amount of composite mineral admixture,the water content of concrete cube,and the sand ratio.Through compressive test on cube samples at 3 d,7 d and 28 d,the compressive strength development of SCAC with different mix proportions were investigated.The results showed that under the condition of 70% usage rate of local materials,the effects of cementing material dosage and water content on SCAC strength were similar to that of normal concrete. The combination of increasing cementing material dosage and reducing water content could improve the 28 d compressive strength up to 58 MPa.The appropriate amount of composite mineral admixture could effectively slow down the early strength development of SCAC,and helped for the long-term strength growth.Decreasing the maximum particle size of aggregate led to increased compressive strength of SCAC,but the extent of this effect was gradually decreased with age.The increase in strength owing to increase of sand ratio was found significant in the mixture with low water-binder ratio,but the sand ratio should be controlled within a reasonable range.