Evaluation of pavement material hydraulic performance using a laboratory-scale rainfall simulation prototype

Climate change is expected to increase the frequency and intensity of extreme weather events, including more intense rainfall, which underscores the need for effective water management strategies. For many years, water has been considered a detrimental factor for infrastructure durability, leading to the widespread impermeabilization of surfaces, which increases runoff and reduces water infiltration. Recently, for some pavement structures, in particular urban roads, there has been growing interest in reversing these effects by using materials that make pavement structures more water friendly. However, a comprehensive understanding of their hydraulic properties—such as runoff coefficients and infiltration kinetics—is still required for proper pavement design and maintenance. This paper presents initial results from tests conducted on a novel laboratory-scale rainfall simulation prototype developed to evaluate the hydraulic behavior of pavement materials. The experimental setup includes a custom-designed rainfall simulator, runoff and infiltration quantification systems, and Time Domain Reflectometry (TDR) sensors for monitoring moisture content. Four material types were tested: two surface bituminous materials (one porous and one non-porous) and two base materials (one bituminous porous and one untreated conventional gravel).