The Usage of Additives on Porous Asphalt

Abstract

Roads are an important infrastructure component, but often face problems such as changes in temperature, humidity, and standing water. To overcome this problem, a layer of porous asphalt which has air voids to reduce standing water on the road surface can be a solution. However, although porous asphalt has water-related benefits, its structure is less durable and requires increased resistance. Therefore, this study aims to analyze the effect of adding additives on the strength, permeability, and porosity of porous asphalt. Three types of additives studied were crumb rubber (CR), nano silica (NS), and Wetbond-SP. Several laboratory tests were conducted on the prepared specimens, namely the Marshall, Cantabro Loss, and permeability tests. The results showed that adding NS onto the specimen was able to increase the stability value of porous asphalt, while the addition of CR and Wetbond-SP had no significant effect on the stability parameter. However, the addition of Wetbond-SP improved the adhesion between the aggregate and asphalt, resulting in a denser mixture. The three additives also increased moisture resistance and cohesion loss in the mixture, as indicated by a decrease in Cantabro Loss (CL) percentage. Additives also impact the permeability and porosity values, where adding more additives in the mixture will reduce the permeability and porosity values. Based on the results of the study, the optimum concentration of CR added was 1% of the total weight of the mixture, NS was 4% of the weight of asphalt content, and Wetbond-SP was 0.4% of the weight of asphalt content.