Bond of epoxy-coated reinforcement to seawater coral aggregate concrete

The bond between epoxy-coated reinforcement (ECR) and seawater coral aggregate concrete (SCAC) were studied by using a series of pull-out tests. Five different parameters were considered in this test: types of concrete (SCAC and ordinary concrete (OC)) and reinforcement (ECR and ordinary reinforcement), the ratio of bond length to reinforcement diameter (3, 5 and 8), and concrete strength (C25 and C35) and thickness of concrete cover. The failure mode, bond-slip curve and strength of specimens were analyzed. Typical failure mode of pull-out specimen was splitting failure, while the failure surface of SCAC specimen was different from that of OC specimen. Test results indicated that the bond strength of specimen with SCAC was high compared to specimen using OC even under the similar concrete strength. Seawater coral aggregate concrete-ECR (SCAC-ECR) bond strength decreased with increasing bond length and decreasing concrete strength and thickness of concrete cover. The bond-slip curve of SCAC-ECR was similar to that of ordinary concrete (OC)-ordinary reinforcement (OR). However, SCAC and ECR reduced the bond-slip curve curvature. The decline of curve was improved by using ECR. Finally, an analytical expression for bond stress-slip curves was proposed. The obtained results provide a basis for the application of reinforced SCAC.