Effect of Layer Thickness on Performance of Two-Layer Pervious Concrete Paving Mix: A Case Study

Abstract

This study investigates a two-layer pervious concrete (2L-PC) system designed specifically for low-volume rural roads with the dual goals of maximizing mechanical strength as well as hydraulic performance-two parameters otherwise having conflicting requirements in pervious pavement. Contrary to conventional single-layer systems, this approach utilizes two different aggregate sizes (19 mm and 9.5 mm) in different depth configurations to determine their effect on compressive strength, permeability, density, water absorption, and void content. Six mix configurations were formulated and tested according to the Indian Roads Congress (IRC) guidelines applicable to M30-grade concrete mix used for rural roads. The test results showed that the finer aggregates not only enhanced structural performance, but also led to lower permeability. Among all the mix combinations tried, the same with 60%-19 mm and 40%-9.5 mm provided the best-balanced performance reaching near target compressive strength without significant compromise in water infiltration capacity. Further, Pearson correlation analysis substantiated the strong interrelation among strength, porosity, and permeability. The results present the success of the two- layer mix designs in resolving the strength–permeability trade-off, thus offering a scalable and practical solution towards the development of sustainable rural road infrastructure.