Effects of size and shape on the crushing strength of coral sand particles under diametral compression test

As a brittle material, coral sand particles are characterized by their irregular shape, complex internal structure, and high strength variability. This study used the Weibull statistical method to analyze the crushing strength of single coral sand particle. In this study, the diametral compression test was conducted on 200 coral sand particles that were divided into two groups according to their equancy (E = I/L*S/I, where L, I, and S represent particles’ long axis, intermediate axis, and short axis, respectively.) Based on the resulting force-displacement curves, four types of particle breakage are summarized. Based on the resulting survival probability curves, an inverse correlation between size and strength of coral sand particles is pointed out. Moreover, those particles’ circularity values (C, a parameter to describe the form and roughness of the particle) were obtained through image processing and analysis. Based on the analysis of the circularity-strength relationship of those particles, with the help of the Weibull statistical method, a positive correlation between circularity and strength of coral sand particles is found. Finally, this paper introduces parameter equancy to analyze the relationship between equancy and strength of the concerned particles, and by applying the Weibull statistical method, a positive correlation between equancy and strength of those particles is found.