Laboratory investigation of OGFC-5 porous asphalt ultra-thin wearing course. (20th September 2019) - Hu, Mingjun
Highlights: Durability, void distribution characteristic, shear resistance and interlayer shear strength of OGFC-5 asphalt mixture were investigated. Larger asphalt viscosity and asphalt film thickness leads to better water stability and raveling resistance of OGFC-5 asphalt mixture. The average void size and the proportion of large void have an obvious influence on the water permeability of OGFC asphalt mixtures. OGFC-5 asphalt mixture has a slightly larger cohesion strength and a smaller internal friction angle than coarse ones. Abstract: Porous asphalt ultra-thin wearing course is an efficient preventive maintenance treatment to improve road performance and prolong its life. Due to the high porosity of porous asphalt mixture, it provides high drainage capacity and reduces noise, hydroplaning, water splash and spray. However, the high porosity of this mixture also leads to a decreased strength and raveling resistance in comparison to dense-graded wearing course. Hence, in this study, the durability, void characteristic, shear resistance, and interlayer shear strength of OGFC-5 porous asphalt ultra-thin wearing course (OGFC-5) were investigated through laboratory test. Durability test results show that OGFC-5 can achieve good water stability and raveling resistance when the thickness of asphalt film increases to 14 μm and the viscosity of asphalt increases to 35, 000 Pa.s. Void characteristic test indicates that finer OGFC (OGFC-5) has a smaller void size, a less proportion of large voids than coarser ones (OGFC-10 and OGFC-13), which results in a lower water permeability of OGFC-5 asphalt mixture. Shear resistance test shows that finer OGFC (OGFC-5) has a slightly larger cohesion strength and a smaller internal friction angle than coarser ones. Additionally, the interlayer shear strength of OGFC-5 was obviously affected by test temperature, tack coat type, and application rate. The interlayer shear strength of OGFC-5 is at the maximum when the application amount of tack coat is 0.8 kg/m 2 . The experimental results in the study provide a technical support for the application and promotion of porous asphalt ultra-thin wearing course.