Impact characterization of coral aggregate reinforced concrete beam: A 3D numerical study

Abstract

Coral aggregate concrete (CAC), an innovative construction material, utilizes abundant marine resources, including coral aggregates and seawater. In the realm of reef engineering, CAC is widely used in structural elements such as reinforced beams and columns. This paper presents a three-dimensional (3D) mesoscale model to assess the impact behavior of coral aggregate reinforced concrete beams (CARCB), incorporating the heterogeneity characteristics of CAC and the explicit simulation of reinforcement components. The 3D mesoscale modelling approach developed in this paper was validated by previous experimental data of CARCB, and used for extensive parametric studies evaluating effects such as concrete strength grade, reinforcement ratio, and impact velocity on the static and dynamic bending behaviors of CARCB. Finally, based on the mesoscopic cracking process and damage patterns of CARCB under static and dynamic loads, this study illustrates the corresponding macroscopic mechanical behaviors and failure mechanisms. Results indicate that the predominant forms of flexural failure in CARCBs are tensile cracking in the mid-span region and diagonal shear cracking. Results demonstrate that the predominant forms of flexural failure in CARCBs are tensile cracking in the mid-span region and diagonal shear cracking. Specifically, local bending failures and symmetrical diagonal shear cracks were evident in the CARCBs subjected to dynamic loads, closely resembling those in ordinary concrete beams. With increasing concrete strength grades (C30 to C60) and reinforcement ratios (0.9 %–1.7 %), a significant reduction in the mid-span ultimate deflection of CARCB is observed, indicating enhanced impact resistance. Additionally, as the impact velocity increases from 1 m/s to 50 m/s, the mid-span ultimate deflection of CARCB is magnified by a factor of approximately 200, indicating intensified dynamic damage to CARCB with increasing impact velocities.