Statistical investigation of aggregate size and shape impact on porosity and compressive strength of pervious concrete

The shape and size of aggregates are rarely investigated in pervious concrete research despite their impact on porosity and compressive strength. This study analyses the impact of size and shape distribution of aggregates and mix design on compressive strength and porosity of pervious concrete. 486 specimens of 81 different designs (aggregate-size, aggregate-shape, aggregate-to-cement ratio and compaction) were investigated. Compressive strength was measured after 28 days of curing. The porosity of samples was estimated as theoretical porosity (computed from constituent ratios) and measured porosity (using water displacement). Data visualisation was used for pattern recognition while ANOVA, Post-hoc and Bayesian independent t-Tests were employed to statistically verify effects. A significant impact of aggregate-shape on porosity and compressive strength was observed while aggregate size significantly lesser impact. Aggregate to cement ratio had a larger impact on compressive strength while compaction had a significant yet lower impact. Porosity and compressive strengths had different relationships for different shapes of aggregates.