Study On Preparation And Properties Of Recycled Aggregate Geopolymer Concrete

In this experiment,fly ash and slag are used as raw materials,sand and stone are used as aggregates,under the excitation of alkaline activator formed by mixing sodium silicate and sodium hydroxide,fly ash geopolymer concrete and slag-fly ash geopolymer concrete are maded.The polymer mixture of recycled aggregate was prepared by replacing a certain proportion of recycled aggregate,and the mechanical properties of the polymer were studied under normal temperature curing.In the initial stage of the experiment,the best modulus and liquid-solid ratio were determined.In the preparation stage of the concrete,the liquid-solid ratio,the amount of water reducing agent and the amount of slag were compared to analyze the strength of each parameter influences.Finally,the analysis of the splitting tensile strength,elastic modulus and microstructure of geopolymer concrete are stuided.Study on mechanical properties of polymer concrete with recycled aggregates replaced by a certain proportion of recycled aggregates on the basis of optimal ratio.The research results are as follows:(1)In the geopolymer mortar test of fly ash,when the sodium silicate ’s modulus is 1.4,the liquid-solid ratio is 0.65,and the ratio of sand to sand is 1:1.6,its fluidity and compressive resistance under high temperature curing conditions is better,and the folding strength is relatively good.(2)Analysis of the effects of water reducing agent,liquid-solid ratio and other parameters on the compressive strength,splitting tensile strength and fluidity of geopolymer concrete,it is found that the incorporation of water reducing agent will improve the fluidity and reduce the compressive strength and splitting tensile strength of geopolymer concrete;when the liquid-solid ratio is between 0.35 and 0.65,the greater the liquid-solid ratio,the better the fluidity and the lower the compressive strength,but the reduction is not large and the splitting tensile strength is reduced.The 28 days’ compressive strength under high temperature curing conditions is higher than the compressive strength under normal temperature curing conditions,and the strength under normal temperature curing conditions is up to 50MPa.(3)Adding a certain proportion of slag can significantly improve the compressive strength of geopolymer concrete under high temperature and normal temperature curing conditions,but the fluidity will be slightly reduced.When the slag content is 40%,the fluidity,compressive strength and splitting tensile strength are relatively good.(4)Through the preparation of geopolymer concrete,referring to the strength grade of ordinary Portland cement concrete,it is attempted to determine the proportioning parameters of geopolymer concrete with four different strength grades under normal temperature curing conditions to provide a reference,provide a reference for its application in concrete-filled steel tubular structures.(5)Replacing a certain proportion of recycled aggregate to prepare polymer recycled aggregate concrete,it has the meaning of green environmental protection,and studies its influence on the strength of geopolymer concrete,so that it has good strength under normal temperature curing conditions.(6)The elastic modulus of geopolymer concrete is low,and the elastic modulus increases slightly as the compressive strength increases.(7)According to the SEM image analysis,when the compressive strength of the geopolymer is higher,the powder coal ash glass-microballons will be present in a smaller amount,activated more by the alkaline activator,and the reaction is more complete,the gelled structure is denser.