Experimental Study On Properties Of Pervious Concrete Mixed With Steel Slag Powder And Basalt Fibers

Pervious concrete materials are an important part of the ’sponge city’ and are one of the more economical and practical solutions to the current urban ’flooding’ dilemma.However,its weak mechanical properties and antifreeze properties limit its application scope.In order to improve its mechanical properties and antifreeze properties and expand its application scope,the effect of mixed basalt fiber and steel slag powder on the permeability,mechanical properties and antifreeze properties of pervious concrete is studied by test.The main work and research results are as follows:(1)Study on the optimization of matching ratio and preparation process.The optimum water-cement ratio of 0.3,the appropriate water-reducing agent dose of 0.2%and the optimum silica fume dose of 7% were determined through a preference test.Optimise the forming process of the test blocks and determine the appropriate time for vibration forming of the test blocks to be 10 s.The research explores the demoulding process of the test blocks and proposes a light hammer and heavy impact demoulding method to improve the integrity of the test blocks after demoulding.(2)Study on water permeability.After adding steel slag powder,the effective porosity and permeability coefficient of pervious concrete gradually decrease with the increase of its content.With the increase of fiber steel slag powder,the effective porosity of permeable concrete decreases gradually,while the permeability coefficient increases first and then decreases.When the content of steel slag powder is 10% and basalt fiber is0.10%,the overall water permeability is at the optimal level.At this time,the water permeability coefficient is 2.63mm/s,and the corresponding effective porosity is 15.23%.Appropriate amount of fiber can inhibit the damage of steel slag powder to the permeability coefficient of the test block,but it will destroy the correlation between permeability coefficient and effective porosity.(3)Mechanical properties study.After adding steel slag powder,the flexural strength of permeable concrete gradually increases with the increase of its content,while the compressive strength first increases and then decreases.After adding fiber steel slag powder,they play a synergistic role in improving the compressive strength and flexural strength of permeable concrete,The compressive strength and flexural strength of the optimal group are 39.2MPa and 5.0MPa,respectively,which are 19.9% and 56.3%higher than those of permeable concrete with steel slag powder under the same conditions,and the compression-folding ratio of permeable concrete mixed with fiber steel slag powder decreases continuously,and the flexibility is enhanced to some extent.(4)Frost resistance study.The strength loss rate and mass loss rate of pervious concrete are reduced and then increased with the increase of steel slag powder,and the maximum freeze-thaw grade reaches D50.The enhanced frost resistance of the compound fibre and steel slag powder pervious concrete is mainly manifested in the slowing down of its strength loss rate,and its maximum frost resistance class is increased to D75.Freeze-thaw damage analysis shows that the early frost resistance of the compound fibre and steel slag powder pervious concrete is better and the later damage development is faster.Figure [65] table [29] reference [67]...