The effect of aggregateÆs angularity on engineering properties and performance of porous asphalt

Porous asphalt is a flexible pavement layer with high percent of interconnected air void and constructed using open-graded type of aggregate. Aggregate shape and surface texture plays a vital role in determining the engineering properties and performance of porous asphalt. Angular-shaped aggregate which has a clear defined fracture faces and sharp edges are preferable to be used in asphalt mixture since it encourages better interlocking structures within the aggregate’s skeleton. This study was carried out to evaluate the effect of aggregate’s angularity on engineering properties and performance of porous asphalt using a combination of conventional method and empirical Particle Index Test method. The term of engineering properties includes experimental works to determine the resilient modulus and stability while performance deals with the porosity and durability characteristics of porous asphalt due to variations in the Particle Index Number (Ia). From laboratory data analysis, it was found that angular particles delivers larger Ia number compared to those less-angular or non-angular particles. Significant improvement in the resilient modulus and stability properties has been obtained with application of angular-shaped aggregate. Angular particles also results in higher porosity of mixture but causes undesirable durability performance on porous asphalt against abrasion loss. Some improvements have been recommended to enhance the strength properties and performance of porous asphalt based on engineering explanation