Effect of aggregate gradation on porous asphalt properties

Rainwater or storm water is very common in Malaysia and even at certain time, several places in this country will face the flooding problem. This condition will give a big trouble to the road in Malaysia as majority of them were made by asphaltic concrete. The run off from the rain water if it is not discharge as soon as possible will cause a lot of problem to the road user as well as for the condition of road itself. Based on the previous study, one of this problem solving is by using porous asphalt as wearing course of pavement. In order of that, this study was conducted to evaluate the effect of aggregate gradation on porous asphalt properties. The method is to compare the properties of Grading A and Grading B based on JKR specification (JKR/SPJ/2008) and binder used is PG76 bitumen. The void ratio of the test specimen was controlled in order to ensure the sufficient permeability of porous asphalt. There are several tests was conducted to evaluate properties of the specimen such as abrasion loss test, binder draindown test, resilient modulus test, creep test, and stability test. The test results indicated that gradation affected the performance and properties of porous asphalt mixtures. Grading B showed the best result in term of the physical properties and performance of porous asphalt mixture. The result from both gradations varies caused by difference of the aggregate size proportion of them. The difference aggregate size proportion resulted in difference arrangement of aggregate skeleton in mixture, thus affected the porosity of mixture. It will also affect an ability of granular to resist cyclic load from the pavement surface, and then affected the physical properties of them