Study on the Performance of Ultra-Fine Cement Slurry Reinforced Coral Aggregates and Coral Concrete

Natural coral has irregular shape, dense internal holes and low cylinder compressive strength, which restrict the mechanical properties of coral concrete. The coral coarse aggregate was innovatively reinforced by grouting with ultra-fine cement slurry based on low concentration acetic acid pretreatment in this study. In order to study the influence of ultra-fine cement slurry treatment methods on coral coarse aggregates, 6 different types of coral aggregates and a total of 90 corresponding coral aggregate concrete test blocks were designed, including the physical and mechanical performance test of aggregate, working performance test and mechanical performance test of concrete. The test results showed that the ultra-fine cement slurry could significantly enhance the cylinder compressive strength of the coral coarse aggregate, which increases by 140% after treatment than before treatment. Concrete prepared with reinforced coral coarse aggregates has increased slump and expansion, resulting in improved workability. The cubic compressive strength, axial compressive strength and splitting tensile strength of reinforced coral aggregate concrete increase as the water to slurry ratio of ultra-fine cement slurry decreases and the age of aggregate curing increases. The elastic modulus tends to increase under the influence of water-slurry ratio, but has no significant effect on Poisson's ratio.