Analysis of Porous Asphalt Mixtures Regarding Their Mechanic and Surface Characteristics

Abstract: Porous asphalt (PA) is a specialized type of pavement layer commonly used in flexible pavement systems. Its design features, which include an interconnected network of air voids, enable the rapid drainage of water from the road surface. This drainage capability is particularly valuable in regions prone to heavy rainfall or for roadways with high traffic volumes, where surface water can pose safety risks. By allowing water to pass through the pavement structure and into the drainage system below, PA layers help to maintain a drier road surface. This feature of porous asphalt contributes significantly to road safety by enhancing skid resistance in wet weather, minimizing the risk of hydroplaning, and reducing splash and spray between vehicles. Additionally, porous asphalt plays a crucial role in noise reduction, as its surface structure absorbs tire noise, which is especially beneficial for urban areas and highways near residential zones.

The focus of this study was to analyze the performance and surface characteristics of PA mixtures modified with polymer additives. Specifically, polymer-modified bitumen (PMB) was developed by incorporating styrene-butadiene-styrene (SBS) polymer additives at concentrations of 7%, 7.5%, and 8% into pure bitumen, with two penetration grades: 50/70 and 70/100. Subsequently, porous asphalt specimens were prepared in accordance with the Marshall design method. The Marshall parameters of the specimens were determined, and the Cantabro test (Part Loss), indirect tensile strength (TSR) test, and macrotexture tests were also performed on these specimens. The results obtained from the porous asphalt specimens for different polymer additive ratios, bitumen class, and bitumen ratios were compared. Essentially, the paper suggests that a 7.5%-8.0% SBS additive would be appropriate to meet the criteria for porous asphalt design.