A study on the influence of aggregate shape on the aggregate void ratio and stress-strain performance of pervious concrete (PC)

Aggregate morphology is essential for studying the mechanical properties of PC. This study captures the true morphology of aggregates and classifies them using shape indices such as the Flatness Index (FI) and Elongation Index (EI). The Discrete Element Method (DEM) is utilized to investigate the impact of aggregate morphological parameters on void ratio and pore space distribution. Uniaxial compression DEM numerical simulations are used to evaluate the macroscopic mechanical responses and stress-strain relationships of PCs with various aggregate shapes. The results indicate that regular aggregate shapes can reduce void ratio and enhance load-bearing capacity. While the effect of aggregate shape on the ascending branch of the normalized stress-strain curve is limited, increased aggregate shape irregularity results in a steeper descending branch. Based on this, a stress-strain relationship evaluation equation for PCs with different aggregate shapes has been established, providing a reliable method for predicting their mechanical properties.