Study On Organic Modified Cement-Based Pervious Concrete

With the advancement of the sponge city process,the use of pervious concrete has become more widespread.Due to the pore structure of pervious concrete,it has good water permeability and air permeability,which can effectively infiltrate the superfluous rain water underground.At the same time under the surface of the water will be through the communication hole is evaporated into the air,absorbing a lot of heat,reducing the surface temperature,but also adjust the surface humidity,will not be aware of the hot climate,but also can slow down the city’s "heat island effect".So the application prospect of pervious concrete is very broad.In this paper,three kinds of pervious concrete,which are inorganic pervious concrete with cement as cementitious material,organic pervious concrete with resin as binder and organic modified pervious cementitious pervious concrete,are studied respectively.Through parallel experiments,taking the compressive strength and permeability coefficient of pervious concrete as an index.The influence of factors such as aggregate size and grading,bone cement ratio,water reducer,mineral admixture,sand and resin type and dosage on the properties of pervious concrete were studied.Experimental research shows that:Aggregate size and gradation play a role of skeleton support in pervious concrete,which determines the compressive strength of pervious concrete.In the 9 groups of coarse aggregate grading selected in the experiment,when the aggregate mass ratio is 4.75～10mm:10～16mm=1.5:1,it is the best gradation.At this time,the close-packed porosity of the aggregate is the smallest,reaching37.6%,the preparation of pervious concrete block has the highest compressive strength;The compressive strength and permeability coefficient of the porous concrete are controlled by the bone glue ratio.When the bone glue ratio is 3.9,the pervious concrete has the highest compressive strength and the water permeability coefficient meets the requirements.0.8%water reducing agent and silica fume,fly ash and slag powder three kinds of mineral admixture of double-doped technology can effectively improve the performance of pervious concrete,and the best effect of silica fume content is 6%.At the same time,incorporation of 10%sand can increase the bond point between aggregates and improve the compressive strength of pervious concrete,but has little effect on water permeability.Three different types of resins,polyurethane,methyl methacrylate and epoxy resin E-51,were chosen to study the properties of resin-pervious concrete.Among the three resins,methyl methacrylate has the lowest compressive strength,and epoxy resin E-51 has the highest compressive strength of 26.14 MPa,which is 37.2%and 19.7%higher than that of methyl methacrylate and polyurethane.And the water permeability coefficient satisfies the requirement,so the epoxy resin E-51 is better.The preparation of pervious concrete by using water-based epoxy resin and cement slurry as a cementitious material can solve the problems of low strength,high rigidity,easy cracking and high cost of resin-based pervious concrete.Compared with cement-based pervious concrete,the modified pervious concrete has improved its strength.Through the analysis of stress-strain curves and Paul’s parallel model of pervious concrete,it is not difficult to find that compared with cement-based permeable concrete,the toughness of water-based epoxy resin and cement is 3.22 times that of cement-based,and the elastic modulus is significantly reduced.The toughness of pervious concrete is greatly increased,and the risk of cracking is reduced.