Field Evaluation of Asphalt Concrete Pavement Surface Texture and Skid Charactersitics

The incorporation of safety characteristics into the traditional pavement design or in the functional evaluation of pavement condition has not yet established. The design has focused on the structural capacity of the road way so that the pavement can withstand specific level of repetitive loading over the design life. On the other hand, the surface texture condition was neither included in the AASHTO design procedure nor in the present serviceability index measurements. The pavement surface course should provide adequate levels of friction and ride quality and maintain low levels of noise and roughness. Many transportation departments perform routine skid resistant testing, the type of equipment used for testing varies depending on the preference of each transportation department. It was felt that incorporating the surface texture condition using different methods of testing may solve such problem. In this work, Macro-texture and micro-texture of asphalt concrete pavement surface have been investigated in the field using four different methods (the sand patch method, out flow time method, sand cone method and British portable tester). Two different grain sizes of sand have been utilized in conducting both of the sand patch and the sand cone methods while the microtexture was investigated using the British portable tester method at both dry and wet pavement surface conditions. The test results of the four methods were modeled and correlated to each other and the skid number was determined. It was concluded that such modeling could provide instant data in the field for pavement condition evaluation which may help in pavement maintenance management.