Permeable Cement Concrete Pavement Application Technology In Sponge City

Due to the rapid development of the city,a large number of buildings and the "steel city" formed by the hardening of the ground have prevented the rainwater from penetrating into the ground.At present,the idea of urban rain and flood management is based on "quick drainage" as the main strategy to ensure water safety.The idea of rapid drainage is that it hopes to rapidly transfer rainwater to downstream areas through the pipeline system.However,such measures are still under development The early stage played a role,but it is a measure of risk transfer and can not fundamentally solve practical problems.Municipal Engineering "sponge" committed to combining green facilities and gray facilities,rainwater and sewage collection,transportation,purification,utilization,emissions and other aspects of the organic unity and coordination of operations,to maximize the city’s own drainage and water features.Therefore,the sponge city needs to shift from the traditional mode of concentration of pipelines to ecological and sustainable rain and flood management,which is also one of the important goals of green infrastructure.Sponge city road using LID technology facilities,not only to ensure the capacity of the road,but also to solve the problem of road drainage at the same time prevent the impact of rain on the road stability.As a product of the combination of LID concept and urban drainage system,permeable pavement has been applied to road drainage design in many countries.The main contents of this paper are as follows: Firstly,the research background of sponge city and the main research material —Permeable cement concrete are analyzed;secondly,the situation of rainfall(taking Chongqing as an example)The model was set up to lay a good foundation for further study.Thirdly,the relationship between target porosity,continuous porosity,water-cement ratio,seepage coefficient and strength was analyzed experimentally.The results show that with the increase of porosity,the porosity strength of Permeable cement concrete becomes smaller;on the contrary,the permeability coefficient of Permeable cement concrete becomes larger with the increase of porosity.In the process of increasing the value of water-cement ratio,the strength of Permeable cement concrete is firstly small and then small,while the water permeability coefficient decreases with the increase of water-cement ratio.Finally,using ABAQUS finite element software,Structure model to study the residence time of rainwater in the road to analyze the situation of water storage and drainage of permeable cement concrete pavement.This paper also has the direct instruction for the construction of road construction significance,depending on the situation in different regions,the use of stone as the main Permeable cement concrete’s aggregate,the strength is fully able to meet the road performance,but in the sponge city required permeability is weak,So should choose the appropriate water-cement ratio and porosity for construction.Through experimental simulation and comprehensive analysis of water-cement ratio of 0.28 ~ 0.32,the target porosity of 20% ± 2%,the strength and water permeability can meet the requirements.