Study on the Early Shrinkage Behavior of Coral Aggregate Concrete Reinforced with Ultra-Fine Cement

The shrinkage behavior of coral aggregate concrete reinforced by ultra-fine cement was studied. In this paper, the ultra-fine cement slurry with different water-slurry ratios was used to prepare the reinforced coral aggregate. Three kinds of concrete water -binder ratio (0.21, 0.27 and 0.33) and five kinds of aggregate treatment methods were considered as variables to study the free shrinkage of concrete under the condition of dry curing. In addition, for the reinforced coral aggregate concrete. Three kinds of reinforcement ratios (1.14, 2.05 and 3.24%) were considered as variables to study the shrinkage performance under the constraint of reinforcement. The experimental results show that at the same age, the shrinkage value of coral aggregate concrete strengthened by ultra-fine cement slurry is less than that of coral aggregate concrete after pickling and less than that of natural coral aggregate concrete. The shrinkage of coral aggregate concrete decreases with the decrease of the water-slurry ratio of ultra-fine cement slurry. The higher the ratio of restraint reinforcement, the larger the pore structure and the smaller the shrinkage of coral aggregate concrete.