| The developed countries such as Europe, America, Japan and Korea began to permeable concrete research and development more than fifty years ago. At present, it is widely used in road construction, municipal engineering and landscape engineering and achieves good social benefits, environmental benefits and ecological benefits. In our country, the experimental research of pervious concrete is still in the initial stage though some achievements are obtained. In view of this,"optimization of mixture and its life cycle environment evaluation system" are further researched in this paper. The main contents and conclusions of the paper are as follows:1.On the basis of existing research results, the pervious concrete aggregate gradation theory and principle are summarized. Based on the theory of particle interference and mixture design method, the relationships are established between aggregate gradation and aggregate air void, the unit volume aggregate particle number, and aggregate specific surface area.2.1n Binary cementations’system and multiple cementations’ material system, the effect of different types of mineral admixture content on cement paste viscosity, fluidity of mortars, compressive and flexural strength and other properties is compared and analyzed, the system and parameters of high performance pervious concrete is optimized.3.According to the special structure and function of pervious concrete, its performance evaluation method is improved. Based on the comparison of different feeding mode, molding, curing process the paste, wrapped stone method is put forward, standard curing (temperature:20+2℃, the relative humidity:95%) the preparation process can obviously improve basic properties of pervious concrete, and the mechanical properties increases by10%.4. Optimization analysis was made aimed at the design parameters of pervious concrete mix ratio, and the correlations between aggregate gradation and effective porosity, permeability coefficient and other design parameters were established. The influence law of water-cement ratio, aggregate-cement ratio on mechanical properties and drainage performance of pervious concrete was revealed. The optimized design parameters of mixture ratio were as below:the suitable water-cement ratio was between0.29and0.33, suitable aggregate-cement ratio was between4:1and5:1, suitable sand rate was between6%and10%. The maximum amount of artificial sand should be no more than10%. In addition, this paper proposed an efficient method of high performing of ordinary permeable concrete, such as, by increasing the number of contact points and contacet area, the strength of cement materials can be improved.5. According to "the technical regulation of pervious cement concrete pavement" CJJ/T135-2009, a new mix design method that can reflect the mix design parameters and performance of porous concrete the correlation more accurately is put forward. And Visual Basic language is selected to write PCM pervious concrete mix design software, the result shows that:the software can meet the design requirements, performance prediction results agree well with the experimental data, and it has good stability and reliability.6.Impact of ordinary concrete, ordinary pervious concrete and high performance of pervious concrete on the environment is compared and analyzed by LCA life cycle method, the input-output lists and environmental impact assessment results is obtained, adding fly ash, slag and other industrial waste can reduce raw material significantly,such as limestone, the consume of coal, oil, electricity,and so on energy can also be reduced; nanometer TiO2can decompose harmful gas effectively, and further improve the coordination between pervious concrete and environment. Result of economic analysis is that every square meter high performance pervious concrete is between50.7and154.7yuan every10years. |
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