Optimization Design Of Porous Concrete With Two Kinds Of Mixing Sizes Based On Orthogonal Test And Microscopic Study On Pore Structure

At present,with the increasingly serious global warming,the ozone layer,the greenhouse effect and ecosystem destruction and other ecological and survival issues,people's awareness of environmental protection continues to increase.This requires the society to provide a wide range of ecological materials to protect human resources.Continuous development.At present,with the acceleration of urbanization,cement concrete pavement is laid on a large area,and the surface area with water permeability is gradually shrinking.This has brought a lot of disadvantages to the ecological environment.In the face of increasingly serious water shortages,water resources are seriously affected.Pollution and other environmental issues,the application and popularization of ecological concrete more in line with the current ecological civilization construction requirements,improve the urban ecological environment,and realize the recycling of water is of great significance.In this paper,pervious concrete is taken as the research object,and the mechanical properties and permeability of pervious concrete are strengthened,and the fine microstructure of pervious concrete is studied.According to the research progress of the research group,it was found that the 5-10mm particle size permeable concrete has high strength such as compressive strength and flexural strength,but the porosity is not very high,and the permeation effect is not ideal.The 10-15mm size permeated concrete has a high porosity and good water permeability,but the compressive strength and flexural strength are not too high.Based on the existing problems,to explore whether the blending of two different sizes of stone can not only greatly increase the strength of pervious concrete such as compressive strength and flexural strength,but also increase the porosity of pervious concrete and achieve ideal water permeability.The permeable concrete mix ratio orthogonal test design mainly focuses on the ratio of water to cement,the proportion of stone,and the amount of reinforcing agent.In addition,the mechanical properties,water permeability and microstructure parameters of pervious concrete were studied.Finally,the use of computerized tomography(CT)technology,which is a non-destructive inspection method,discusses the fine-microscopic structure of pervious concrete,and provides a theoretical basis for the popularization and application of pervious concrete in a wider range.The orthogonal test results were used to analyze the influence of water-cement ratio,gravel proportion,and reinforcing agent content on the compressive strength,flexural strength,and permeability coefficient of pervious concrete.The optimal ratio of pervious concrete was obtained through the analysis experiment.The microscopic test of the pre-made permeable concrete specimens was conducted to obtain the three-dimensional pore distribution visual map of the antifreeze permeable concrete.Through the image data,it can be shown that the entire test block is connected,which is of great significance to our study of pervious concrete.The relationship between the cross-sectional porosity and height curve shows that the porosity of all cross-sections of the whole test block is kept within a certain range,indicating that the overall performance of the water-permeability is good,and the distribution volume,diameter,surface area,and sphericity of the three-dimensional pores are measured.Pervious concrete micro analysis provides a certain theoretical basis.Through the experimental research,the main conclusions are as follows:Based on the orthogonal test,the water-cement ratio,the proportion of small and large stones,and the amount of reinforcing agent were designed to greatly improve the compressive and flexural strength and water permeability of the permeable concrete.CT technology was used to analyze the true mesostructure of concrete such as aggregate particles,hardened cement mortar,and pores;the three-dimensional pore distribution visualized qualitatively to show that the entire test block was connected;the relationship between the porosity and height of a single section indicated the entire The porosity of all sections of the test block is kept within a certain range,and the overall performance of the water permeability is good.Through the three-dimensional pore diameter distribution and volume distribution,it is found that the diameter is mainly distributed between 3mm and 7mm;and the pore volume is in the range of0mm~3-40mm~3.In the interval,the size of the pore diameter and the volume range of the pore are more concentrated;the sphericity of the pore is roughly in the range of 0.45-0.65,indicating that the fluidity of the mixture is good and the skeleton structure of the aggregate space is dense,the concrete strength is high;the pores of the concrete The specific surface area tends to be constant,and the adsorption for water is also stable.It is helpful for the concrete's water permeability and it can satisfy the water-retaining function of the pervious concrete.