Research On Application Of Permeable Cement Concrete Pavement In The Construc Tion Of Sponge City Of Changde

In recent years,due to serious waterlogging and drought,China;s natural rainwater resources have not been well used.City rainfall is directly drained into drainpipe without being treated.At the same time,low standard of design is unable to meet the demand of drainage caused by extreme weather or heay rainfall.In order to control the city water problems,China put forward the new concept of city—sponge city.It is constructed to absorb water like sponge when it rains,and to use the purified water when needed.In the process of construction of sponge city,the traditional ordinary concrete is replaced by new permeable concrete.The new concrete is made up of coarse aggregate and cement mortar,different from the ordinary concrete for its penetration of rainwater and pavement runoff.At present,permeable cement concrete is mostly used in surface layer does not have high requirements on strength,such as sidewalks,parking lot,bicycle paths,called the permeable pavement.The construction of sponge city is still in the exploratory stage in China,and the permeable road is a very important section in the whole construction.However,the mix proportion design for permeable concrete is still not mature.In order to promote the construction of city sponge,deeper research must be conducted on the permeable cement concrete.The thesis focuses on the selection of raw materials of permeable cement concrete,mix proportion design,strength,permeability coefficient,sponge city function,construction technology and so on.The specific contents are as follows:1 The paper mainly refers to Technical Specification for Permeable Cement Concrete Pavement and adopts the volume method for the calculation of mix proportion.In the actual operation,volume method is used to calculate mix proportion for performance test,so as to prove the feasibility of volume method.2 Various mixing methods are selected for test,to compare once feeding method,twice feeding method,mixed cement mortar method,cement wrapped sand method,in order to o choose the best way to stir as a test method according to relevant research literature.3 According to the experimental results,the factors affecting the strength and water permeability of permeable concrete are analyzed.4 Combined with o,the runoff water experiment and cooling performance test analysis are carried out in combination of other facilities of sponge city(ecological grass ditch),to analyse cooling performance of permeable concrete and its environmental performance.5 Application in actual construction process...