Experimental Study On Prefabricated Pervious Composite Cement Concrete Pavement

Water and soil are important natural resources in China.Urban and rural transportation construction is closely related to the protection of natural resources.The application research of pervious concrete is also constantly bringing forth the new along with the integration of urban and rural construction.This paper started with the assembly design of pervious composite concrete pavement and analyzed the problems in the application of pervious concrete pavement system.On the basis of improving the performance of the pervious surface layer and the base concrete respectively,the pervious surface layer and the modified base layer were compositely prefabricated by selecting a suitable bonding layer material.The mechanical response of the determined pavement composite structure was analyzed by the finite element software ABAQUS.It was proposed to solve the problems of traditional pervious concrete pavement:hard to balance strength and permeability,easy to empty and crack,difficult to repair and maintain.The effects of aggregate gradation,silica fume content,reinforcing agent content and basalt fiber content on pervious concrete were analyzed by single factor test,and then the orthogonal experiment with four factors and three levels were carried out.The technical indexes of compressive strength,flexural strength,effective porosity and permeability coefficient were evaluated.Based on the optimum ratio obtained from preliminary experiments,the anti-crack water repellent and polyvinyl alcohol fiber were added to modify the C40 base concrete to characterize the mechanical properties,durability and pore structure of the base concrete.By selecting different cement-based interfacial agent,the properties of the composite cement layer with pervious concrete and modified cement-concrete were studied by using different interfacial agents.A three-dimensional finite element pavement composite structure model was established by ABAQUS,and an orthogonal experiment was designed that the side length,surface thickness and base thickness of the composite prefabricated plate were used as independent variables.The main factors affecting the mechanical characteristics of the prefabricated pavement slab were analyzed by using the maximum vertical displacement,maximum tensile stress and maximum shear stress of the pavement under moving load.Through the research on the design of prefabricated concrete pavement system at home and abroad,including the joint design,size and shape design of pavement plate,combined with the characteristics of pervious composite prefabricated plate in this paper,the following conclusions were drawn:(1)It was found that the basalt aggregates had the most significant influence on the mechanical and permeability properties of pervious concrete,and the optimal ratio of pervious concrete was obtained by comprehensive analysis.(2)The modified base concrete had more compact pore structure and durability.(3)When the base layer reaches the initial setting state,J_B cement-based interface agent was used to obtain the best bonding layer performance of the composite specimen.(4)The optimal size of the prefabricated pavement slab was designed,and the vertical stress displacement and shear stress variation rule of each layer of the assembled composite pavement slab were found when the moving load moved to the center of the pavement slab.(5)A prefabricated pervious composite pavement system combining the tongue-and-groove connection of trapezoidal concave and convex grooves with the L-type interface connection was proposed.Figure:[33];table:[42];reference:[65];...