Properties And Microstructure Of Silica Fume And Coupling Agent And PB-g-PS Cement Modifier Complex Cement Mortars

In this paper,the polybutadiene grafted polystyrene(PB-g-PS)latex were synthesised.The PB-g-PS cement modifier was gotten by adding the twain – 20,the performances and microstructure of the polystyrene(PB-g-PS)latex was examined by adding the modifier,silica fume and coupling agent into cement mortar,Theimpact of modifying agent on cement hydration was examined by using DSCand FTIR analytical methods,the detailed steps as under:The PB-g-PS graft copolymer was prepared by using semi-continuous emulsion polymerization technique and was characterized by FTIR.The results showed that,the target product was obtained.The PB-g-PS cement modifier was gotten by adding twain – 20 which accounts for 5% of the latex’s quality into the latex.The silica fume,coupling agent and cement modifying agent were used in modified mortar,when the quality of the water to cement ratio controlledat 0.45,by using adopting water curing methods.Theresults showedthat,asadding a certain amount of silica fume,with the increase in the content of coupling agent,the compressive strength,flexural strength,bulk density of the composite modified cement mortar were inproved,as adding a certain amount of coupling agent,with the increase in the content of silica fume,the compressive strength,flexural strength,bulk density of the composite modified cement mortar were also inproved.The microstructure of modified mortar was investigated by using SEM method.The results showed that,the dendritic structure of latex film and the calcium hydroxide crystal structure were detected from modified mortar.The structure of the calcium hydroxide crystal was appeared to hexagonal flake.The influence of silica fume,coupling agent on the cement hydration wereanalyzed by using FTIR,DSC analytical methods.The results showed that,as adding a certain amount of silica fume,coupling agent added 0.2%,highest degree of cement hydration;as adding a certain amount of coupling agent,silica fume 10%,the highest level of cement hydration.