Integrated approach for analyzing Effects of Surface Permeability on Lomg Term Performance of Asphalt Pavements

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Transportation infrastructures in general and highways in particular plays significant role in the national economy of Canada as well as other countries of the world. Therefore, they require large amounts of investments for building new roads and pavements and maintaining existing networks. However, historically, asphalt pavements have been facing significant problems in terms of building roads that can meet their projected design lives. The early failure of many newly constructed asphalt roads in many parts of the world including Canadians are forcing the governments and road administrators to search and investigate other types of roads such as Portland cement concrete and/or the use of various additives and reinforcing grids to delay the observed early deterioration of asphalt roads. This research investigation builds on the results and findings of early research work carried out by the applicant which applies findings of theoretical and basic research to develop innovative and applicable technologies to achieve the goal of designing and building asphalt pavement roads that will meet their expected long term design objectives. The main thrust of the proposed research is to integrate the effects of construction cracks, permeability, and bond between asphalt pavement layers to model the propagation of thermal transverse cracks. The developed model will be validated using lab and field experiments. The outcome will be used to upgrade the AASHTO Thermal crack predictive model. ****The significance of the research is its impact on the long term performance of asphalt roads in Canada especially under severe cold environmental conditions. The current studies that deal with the phenomenon of thermal cracking do not deal with the “initiation” of the cracks in an integrated manner which considers theoretical, experimental and field studies. This research follows a unique research approach in that it started by developing better understanding of the actual causes of the “initiation” of thermal cracking, support the understanding with preliminary laboratory simulation followed by formulating the basic principles of predicting model of the thermal cracking problem. Significant savings and benefits will result from the research program. First, the understanding of the variables governing the problem will help proposing reliable and effective solutions. Second, reliable solutions will lead to design and production of new technologies to reduce the costs and expenses of maintaining asphalt rods subjected to severe cold weathers such as our Canadian one. The research expected to expand the scientific knowledge of an old challenging problem that has been known for more than a century without a reliable solution. Furthermore, an immediate benefit will be the prevention of the annual reappearance of the potholes on many of Canada's asphalt roads and specially those of its capital city Ottawa.***