Influences of size, shape and strain rate on mechanical properties of single coral particle

Abstract

To understand the roles of particle size, shape, and strain rate on their mechanical properties, the crushing behavior of 800 coral particles with different shape factors and size groups (i.e., 2.36–4.75 mm, 4.75–9.5 mm and 9.5–16 mm) at various loading rates (i.e., 0.06 mm/min, 0.6 mm/min, 3 mm/min and 10 mm/min) are studied. The results show that the particle crushing strength and Young's modulus perfectly conform to the Weibull statistic law. Particle crushing strength decreases with an exponent of (−0.816) of particle size and increases with an exponent of 0.062 of strain rate, and a mathematical model incorporating particle size, shape, and strain rate is proposed to explain the change of characteristic crushing strength. Additionally, irregularity, elongation, and flatness strongly relate to the crushing strength and Young's modulus, and establish a functional relationship with the geometric similarity parameter of the Weibull model. The fragmentation behavior is classified into three typical modes, and the change of fragmentation modes is affected by particle size, strain rate, and irregularity. Young's modulus calculated by Hertz theory is 0.7–0.9 GPa. The characteristic Young's modulus is in descending order of rodlike, flaky, blocky, and dendritic particles, hardly influenced by particle size and strain rate. The results can provide a reference for the microscopic numerical analysis of coral concrete.