Experimental Study On Influence Factors Of Permeable Concrete Properties

Pervious concrete has the advantages of improving water resources,reducing urban floods,and reducing urban “heat island effect”.However,due to its low strength,the application is not widespread enough.Therefore,perfecting the permeability and mechanical properties of pervious concrete,promoting the promotion and application of pervious concrete,and better building a “sponge city” are of great significance.In this paper,through theoretical analysis and experimental research,research work has been done on the influencing factors of pervious concrete performance.The main research contents and research results are as follows:(1)Through the study of the mechanism of pervious concrete performance,it was found that the four factors of aggregate grading,thickness of slurry film,water-binder ratio and replacement rate of silica fume all have great influence on the performance of pervious concrete.The use of crushed stone,42.5R ordinary portland cement as raw material,silica fume,polycarboxylic acid water reducer and tackifier as admixtures,secondary feeding method for the preparation process,standard box maintenance and other methods to prepare permeable concrete Suggest.(2)The influence of thickness of slurry film,aggregate grading,water-binder ratio and replacement rate of silica fume on the compressive strength of permeable concrete was studied.The compressive strength first increases and then decreases with the increase of the thickness of the serosal,and reaches a maximum at a serosal thickness of 1.0 mm,and then decreases.The denser the aggregate,the greater the compressive strength.The compressive strength reaches its maximum when the water-binder ratio is 0.30,and then decreases with increasing water-binder ratio.The compressive strength reaches a maximum at the replacement rate of silica fume of 6% and then decreases.(3)The effects of film thickness,aggregate grading,water-binder ratio and replacement rate of silica fume on the porosity and water permeability of pervious concrete were studied.The porosity decreases with the increase of the thickness of the slurry film;the denser the aggregate accumulation,the smaller the porosity;at the optimum water-to-binder ratio of 0.30,the porosity is small;the porosity increases with the replacement rate of silica fume And decrease.The factors that affect the permeability coefficient and porosity are basically the same.(4)Through the test data,the relationship between porosity,permeability coefficient and compressive strength was fitted to obtain the calculation formula between the test targets.The porosity is proportional to the water permeability coefficient.The greater the internal porosity,the more interconnected pores are formed,and the better the water permeability is.The compressive strength is inversely proportional to the porosity,the porosity increases,the area of the internal aggregate joints decreases,and the compressive strength decreases.The compressive strength is inversely proportional to the permeability coefficient.The permeability coefficient depends mainly on the interconnected porosity.Therefore,the greater the permeability coefficient,the lower the compressive strength.However,the relationship between them is also related to factors such as the ratio design,preparation process,and maintenance methods in the preparation process.