Impact response and constitutive model of basalt-polypropylene fiber-reinforced coral aggregate concrete

Abstract

Basalt-polypropylene fiber-reinforced coral concrete (BPFRCAC) is a popular choice for engineering materials in the reef environment, but the dynamic behavior of BPFRCAC under extreme dynamic loads remains unclear. This study explores the impact response of BPFRCAC at strain rates ranging from 31 to 141 s−1 using split Hopkinson pressure bar (SHPB). It examines the effects of strain rate on the dynamic mechanical properties of BPFRCAC, and establishes quantitative models of the relationship between the strain rate and key mechanical parameters, including dynamic compressive strength, critical strain, dynamic elastic modulus, and toughness index. The results showed that these properties of BPFRCAC are significantly influenced by the strain rate, showing increases that correlate with the strain rate. The addition of basalt fibers (BF) and polypropylene fibers (PF) not only mitigates the failure extent of BPFRCAC but also enhances the strain rate's impact on its dynamic compressive strength and dynamic modulus of elasticity, particularly when both fibers are mixed. The failure modes of BF and PF depend on the strain rate; at lower strain rates, the probability of fiber pull-out is higher than at higher strain rates, where BF and PF are more likely to snap. A viscoelastic dynamic damage constitutive model suitable for BPFRCAC is proposed, which accurately describes the dynamic mechanical behavior of BPFRCAC. These findings provide important design insights into the use of BPFRCAC under impact conditions, and promote its wide application in reef construction projects.