Better Asphalt Essay Example | Topics and Well Written Essays - 500 words

Better Asphalt - Essay Example Several major research projects have taken place and are currently in progress. The National Cooperative Highway Research Program has a major study currently underway to evaluate skid resistance. The study is not yet complete, but it does show promise in offering improvements in skid resistance through the use of finer grade aggregates. However, due to the fine grade of the aggregate, water may be slow to run off and create a wet condition hazard. Friction is created where the rubber meets the road. The composition of the open coarse grade and its components are a first consideration. The microtexture, the fine aggregate in an asphalt mixture, is most influential force creating the necessary surface friction between the pavement surface and automobile tires (Williams). Over time, the surface wears away and exposes the coarse aggregate. Coarse aggregate size becomes a major consideration on the surface to improve skid resistance. Recent tests in the United Kingdom has indicated that 6 to 10 mm chips at a 1.4 mm depth offered improved skid resistance at high speeds (United States Department of Transportation).