Experimental Research On Permeable Concrete Prepared By QIAN GANG Unaged Steel Slag As Addregate

To save non-renewable natural aggregate resource and rational use of large emissions,low utilization rate of steel slag solid waste,made the permeable concrete by using the unaged steel slag as aggregate.In this paper,mainly research on the influence of the paste thickness on coated aggregates,water-cement ratio,aggregate diameter,admixture and auxiliary cementitious materials to the strength and permeable performance of the permeable concrete.On this basis,using boiling and autoclave test method,also research the volume stability and improvement method.Microscopic analysis has also been conducted through XRD and FT-IR.The results show that:with the increase of paste thickness and water-cement ratio,the compressive strength of steel slag permeable concrete increases and the permeability decreases.The strength and permeability of permeable concrete prepared by aggregate with particle size of 4.75-9.5mm are better on the whole,and the comprehensive performance of steel slag permeable concrete compounded with two kinds of aggregate with similar particle size is better.Consistency has great influence on the strength and permeability of permeable concrete.Adding silica fume and steel slag powder can raise the strength of porous concrete,to reduce the permeable performance,adding fly ash and steel slag powder can raise the strength of porous concrete,but with the increase of the dosage of fly ash,the intensity of the effect will be decreased,adding to redispersible latex powder can improve the strength of porous concrete,and little effect on the permeability;The porous structure of permeable concrete can alleviate the damage of its volume expansion,the greater the porosity,the better the volume stability.Silica fume and steel slag powder,fly ash and steel slag powder,redispersible latex powder can all improve its volume stability to varying degrees.The smaller the particle size is,the worse the stability of permeable concrete is.The volume stability of permeable concrete can be improved by using waste concrete recycled aggregate to replace some steel slag aggregate.The volume stability of permeable concrete can be improved to a certain extent by pretreatment of steel slag aggregate at 80?1d.The volume stability of permeable concrete can be improved by adding silica fume and steel slag powder,but the amount of steel slag powder should not be too much.The volume stability of steel slag permeable concrete can be better improved by pretreating steel slag aggregate with water heat of 80?1d and adding silica fume and steel slag powder at the same time.The permeable concrete made of steel slag aggregate and auxiliary cementitious material containing steel slag powder has excellent mechanical properties,permeable properties,wear-resisting properties and anti-freezing properties.The microscopic test show that:f-Ca O in unaged steel slag is the main factor affecting the volume stability of permeable concrete.The volume stability of waste concrete recycled aggregate is improved by reducing f-Ca O in the system after replacing steel slag aggregate.The redispersible latex powder can resist the expansion and damage mainly by improving the bonding ability of slurry.The hydrothermal pretreatment of the aggregate can make the partial f-cao in the steel slag aggregate predigestion hydration to generate Ca?OH?₂,so as to reduce the expansion failure of the pervious concrete after hardening.Silica active admixtures improve their volume stability mainly by consuming Ca?OH?₂ produced by f-Ca O hydration.Therefore,the combination of hydrothermal pretreated aggregate and siliceous active admixture is more conducive to reducing the expansion failure of steel slag permeable concrete and improving its volume stability.