Influence of Warm Porous Asphalt on Permeability Reduction Due to Binder Flow

Abstract

Warm mix asphalt (WMA) is a new technology in Malaysian context. The technology can help to reduce the global warming issues. In this research, the warm mix asphalt technology was used in porous asphalt pavement which is known as warm porous asphalt (WPA) mix. WPA loses permeability mainly due to clogging. Apart from typical clogging agents such as dust and tyre rubber, the binder flow is also another source of permeability reduction. The objective of this study was to investigate the binder flow phenomenon that affected the permeability reduction in WPA. To obtain the binder flow phenomenon, samples were conditioned at 35 °C for 120 days. The different mixing and compaction temperatures with bitumen 60/70 + 3 % RH-WMA additive were used in preparing the samples. A falling head water permeameter was used to determine the permeability loss which is related to time and temperatures. The result from the permeability loss was significant to high mixing temperatures over time. Due to time, self-weight of the binder and high mixing temperature, the asphalt mastic start to flow down according to gravitational forces and finally the coefficient of permeability reduced, yet the time of flow increased. The outcome of this research indicated that the different temperatures during mixing and compaction were significant to the binder flow. Hence, the low mixing temperature using WMA technologies could reduce the clogging problem due to self-weight of the binder.