Study On Heavy Traffic Asphalt Pavement Base Of Porous Concrete In Cold And Rainy Area

The project is located in the Hulun Buir area of Inner Mongolia which belongs to the temperate continental climate, winter is cold and long, summer is warm and cool but short. The precipitation is centralized, heavy shower happens sometimes, the frost-free season of a whole year is short. Perennial engineering experience shows that water damage is the main form of local asphalt pavement failure. In order to enhance the drainage capacity of the road, reduce the damage caused by water accumulation after freeze in winter and intense fall in summer, and prolong the service life of the road, a systemic study on the porous concrete with excellent drainage performance was made, and the feasibility of its use as a high grade highway base in the cold area was analyzed.The paper mainly carries on the research of five aspects. First, though experiments and theoretical analysis, the methods of forming and test parameters of porous concrete were determined, the design method of mixture’s proportion for porous concrete was put forward; Second, connected porosity, which is an important factor affecting drainage performance of porous concrete was systemic studied, and the relationship between the target porosity and the connected porosity was analyzed. Third, drainage performance of porous concrete was tested by proprietary equipment, the relationship between the connected porosity and the frost resistance property and the permeability performance were analyzed, the shrinkage performance of porous concrete was compared with that of semi-rigid material.Fourth, the relationship between the connected porosity and the strength and modulus of porous concrete were analyzed.Finally, initially proposed pavement structures were designed and calculated by Bisar3.0, feasibility of porous concrete for heavy traffic asphalt pavement base was analyzed, and compared with cement stabilized macadam base.The research results show that, the methods of one time feeding and standard shaking machine were more applicable to porous concrete’s mixing and shaping, when the water cement ratio, mixing time and vibration time were 0.26,30 s and 40 s, the molding effects were the best. The design method of porous concrete’s mixture: grading design- target porosity determination- determination of test control parameters- calculation of mix proportion-workability test of new mixed concrete – verification of technical performance of concrete was proposed. The difference between the connected porosity of the porous concrete and the target porosity is 1.5% ~ 3%, and there is a good correlation between both, the connected porosity can be predicted by the target porosity in practice. Porous concrete has a excellent road l and mechanical performance, its shrinkage characteristic is better than semi-rigid base material and there’s a good dependency between its connected porosity and performance. When the target porosity of porous concrete is 15%,which can meet the needs of the base course of heavy load traffic asphalt pavement, and have effects on water damage.