Abstract: The performance of the coral reef sand concrete mixed and cured by the seawater is significant to the construction of islands and reefs in the South China Sea. In order to study the compressive strength of those concrete samples, the uniaxial compressive strength of 100 × 100 × 100mm test cubes under different ages (3d, 7d, 14d, 21d, 28d) were tested, and the cement types, watercement ratio and other factors that might affecting the strength of concrete were explored. The results indicated that, the performance of coral sand concrete cube compressive strength variation is consistent with the ordinary gravel concrete. The range of the compressive strength increases with the decrease of watercement ratio; and the higher the cement grade, the higher the ultimate compressive strength is. With the same strength index, the mix design with Portland cement has the lowest strength. In the practical coral reef construction engineering, a strength index of 425 should be used.

Key words: Coral Reef Sand Concrete, Curing Age, Uniaxial Compressive Strength, Cement Type; , WaterCement Ratio