Research On Preparation And Properties Of No Sand Internal Hydrophobic Pervious Concrete

With the advance of urbanization,a large area of impervious materials are used in urban construction,causing serious harm to the ecological environment.Such as heat island effect,urban waterlogging,shortage of groundwater,ground subsidence and surface runoff pollution.Pervious concrete is an eco-friendly concrete.Some developed countries have made good research on their research and application,and have achieved good ecological and social benefits in municipal engineering and garden engineering.In recent years,China's research and application of permeable concrete is positive,but still in its infancy.In this paper,a new type of architectural coating modifier(lotus leaf hydrophobic agent)into the development of pervious concrete.The main contents and achievements of the study are as follows:(1)It is appropriate to apply the volume method to the design of the internal hydrophobic concrete mix.(2)In this study,the combination of the empirical method and Vibe consistency method can be used to evaluate the workability of pervious concrete more accurately.(3)The addition of lotus leaf hydrophobic agent,the permeability of concrete has a certain increase,Compressive strength of test had a maximum increase of 38 percent.(4)According to the influence of porosity,water-cement ratio,hydrophobic agent content and aggregate type on the strength and water permeability of permeable concrete,recommended the porosity is 20 percent,The water-cement ratio is between 0.24 and0.28,the lotus leaf hydrophobic agent content of 4%,aggregate use 9.5~11.5mm larger size aggregate.(5)A compressive strength of 28.7Mpa,permeable coefficient of4.11mm/s and flexural strength of 4.47 Mpa was prepared.(6)The permeability coefficient was tested by using a self-made water permeable instrument.The relationship between the permeability coefficient and the effective porosity was established.When the effective porosity was more than 23.8%,the water permeability coefficient of the hydrophobic concrete would be higher than that without adding the hydrophobic agent(7)Internal hydrophobic concrete microstructure is more dense,and has a uniform waxy small bumps,the formation of lotus leaf hydrophobic effect,which is consistent with the theoretical study of this paper.