Mesoscopic mechanical study on quasi-static compression of coral aggregate seawater concrete after high temperature exposure

Abstract

Coral aggregate seawater concrete (CASC) is a pioneering concrete made by blending and curing coral reefs, coral sands, cement, mineral admixtures, chemical additives, and seawater. The investigation of its mechanical properties is important for both theoretical and engineering purposes. This paper aims to investigate the quasi-static mechanical properties of CASC after exposure to high temperatures using a combined approach of experiments and numerical simulations. The simulation uses LS-DYNA software and a three-dimensional random aggregate mesoscopic model to analyze the process of concrete damage and crack propagation. Various mechanical parameters such as peak stress, peak strain, and compressive strength after exposure to different temperatures are calculated. The simulation results show that under quasi-static uniaxial compressive loading, microcracks initiate within the mortar and interfacial transition zone (ITZ) of CASC. These cracks then propagate through the coarse aggregates, leading to aggregate failure and the disintegration of the concrete structure. The macroscopic damage traits of CASC specimens reveal concentrated damage in the central region. As the temperature increases during heat treatment, the severity of damage to CASC specimens also increases. However, as the strength grade increases, the damage condition of CASC tends to improve.