Influence of Aggregate Size Distribution on the Mechanical and Hydraulic Performance of Pervious Concrete

Abstract

Pervious concrete is an environmentally sustainable construction material with significant potential for mitigating stormwater runoff, enhancing groundwater recharge, and reducing urban heat island effects. This study investigates the influence of aggregate size and blend on the fresh and hardened properties, infiltration rate, and compressive strength of pervious concrete providing guidance for optimal mix design balancing strength and permeability. Six mixtures were produced using single aggregate sizes (9.5 mm, 13.2 mm, and 19 mm) and 50:50 blended combinations (9.5 + 13.2 mm, 9.5 + 19 mm, and 13.2 + 19 mm). Key properties evaluated include fresh and hardened density, void content, infiltration rate, and compressive strength at 7 and 28 days. The effect of 5% colour pigment on the compressive strength of the 9.5 mm aggregate mix was examined. Empirical relationships were developed between density and void content, hardened density and compressive strength, and hardened void content and infiltration rate at 7 days, supported by graphical analysis. Results indicate that infiltration capacity and porosity are strongly influenced using single versus blended aggregate sizes. Density was found to be an effective predictor of compressive strength and void content, while void content reliably predicted infiltration rate. Hardened density ranged from 1845.14 to 2071.99 kg/m³, with void contents between 20.14% and 33.03%. Infiltration rates varied from 0.45 to 1.00 cm/s. The highest compressive strengths were 8.52 and 11.1 MPa for 7 and 28 days respectively using the 9.5 + 13.2 mm aggregate blend. Colour pigment reduced compressive strength by 18% at both curing ages.