Reasearch On Preparation And Performance Of Porous Cement Concrete Pavement Material

The porous concrete is a kind of environmentally-friendly concrete with continuous porosit mixed with special technology.It has certain intensiy and permeability of air and water.Pervious pavement,whinc uses the porous concrete,can permit rain and storm water run off to percolate throug it rather than flood surrounding areas or storm drains,enhance drivingsafety and comfort by preventing water spray,hydroplaning and decrease of skidding duing rain,noise reduction and alleviate the effect of urban heat island.The conclusions can be drawn investigation as following:First,the paper analysis the structure characteristics of the porous concrete,the physical and machanical properties of these mixtures were studied in detail.Compressive and flexural strength were both studied in detail.Second,the paper also outline the research on the acoustic property of porous cement concrete,both mechanism of tire-pavement interaction noise and noise propagation were studied.The acoustic absorption coefficient of porous cement concrete were determined using an impedance tube.lt studies the relations among of w/c ratio,porosity and strength,recommends the best range of w/c ratio 0.22～0.26,the goal porosity 15%～20%.What's more, using pulverized fuel ash and silica fume to enhance the strength of the porous concrete,the paper recommends the best ratio of pulverized fuel 20% and silica fume 6%,and the two smaller-sized aggregate mineral mixture best ratio is 10%-6%.Third,the paper analyzes the strengthy effect of the polypropylene fiber on the porous concrete,and drive the index of fiber/cementslurry to control the dosage.The experiments indicate that polypropylene fiber can speacially enhance the strength of bending.When the dosage,variety and specifications changes,the effect dissimilar with others.Forth,noise reduction and drainage and environmental protection function of the porous concrete are studied in detail.The paper also proposes the rational porosity and thickness,and do some research of permeability coefficient.