Study On Rheological Properties And Application Of Polymer Cement Slurry

The difference between polymer cement paste and ordinary cement paste is that in the polymer cement more organic polymers can be dispersed in water.The addition of redispersible polymer powder and cellulose ether can effectively improve the water retention and adhesion of cement paste or the cohesiveness,flexibility and so on.This article mainly focuses on the rheological properties of redispersible polymer powder-cellulose ether polymer cement paste,and studies the effect of mix ratio on the rheological behavior of polymer cement paste.Furthermore this paper combines the rheological properties of polymer cement mortar with its application.The main findings are as follows:(1)The incorporation of cellulose ether changed the rheological properties of polymer cement mortar.The cement mortar without cellulose ether belonged to the expansion plastic fluid with yield value;and the cement mortar with cellulose ether belonged to pseudoplastic fluid with yield value.The shear stress increases with the:increase of shear rate,viscosity decreases with the increase of shear rate,and shows the phenomenon of shear thinning.The polymer can significantly improve the workability of the mortar,The larger the amount of latex powder and cellulose ether is,the greater the plastic viscosity of polymer cement paste is,the more cohesive the slurry is,the more stable the slurry is,and tihie higher the content of dispersible emulsion powder is,the higher the plastic viscosity of polymer cement paste is from 1%to 2%,and the plastic viscosity is increased by 63.47%when the content of redispersible emulsion powder increases from I%to 2%.(2)At the same shear rate,the larger the ratio of fly ash to sand,the smaller the shear stress and apparent viscosity of polymer cement paste.The effect of particle gradation on the rheological parameters of polymer cement mortar is greater,with the increase of the ratio of 70 mesh sand to the total sand mass.When the mass ratio of 70 mesh sand to 25 mesh sand is 2:3,the yield stress of mortar first increases and then decreases,and the plastic viscosity decreases first and then increases,the yield stress reaches a maximum and the plastic viscosity reaches a minimum.This shows that at this time,the adhesion and friction between the particles in the mortar are the smallest,the cohesion force is the largest,and the easy flow is difficult to segregate.(3)The addition of mineral admixture does not change the rheological properties of polymer cement paste with shear thinning,but the effect of the addition of mineral admixture on the rheological properties of polymer cement mortar is different.The effect of mineral admixture on the rheological properties of polymer cement paste was analyzed in combination with the particle characteristics of mineral admixture.The relationship of yield stress between the four admixtures is as follows:silica fume polymer cement net.Slurry>metacolinite polymer cement paste>fly ash polymer cement paste>slag polymer cement paste.(4)When the content of silica fume and metakaolin increases,the yield stress of polymer cement paste increases and the growth trend is the same.When the content of silica fume increases from 5%to 10%,The yield stress of slurry increased by 68.27%and the content of metakaolin increased from 15%to 20%.The yield stress of slurry increased by 56.05%.The yield stress and plastic viscosity of polymer cement paste mixed with fly ash and slag varied with the content of cement,and the variation law of yield stress and plastic viscosity of polymer cement paste with addition of fly ash and slag were similar.The plastic viscosity of polymer cement paste increases with the increase of fly ash and slag content,and the yield stress increases with fly ash and then decreases with the increase of slag content.For 20%fly ash and 10%slag,the yield stress of slurny is 19.247 Pa?13.984Pa.Fly ash and slag content increased,and the yield stress of polymer cement mortar first increased and then decreased,and the plastic viscosity first.Reduction and increase,reaching a minimum at 10%,respectively 42.670 Pa·s,56.662 Pa·s.This is related to the specific surface area.Among the four admixtures,the specific surface area of silica fume and metakaolin is similar,fly ash and slag,he specific surface area is similar.(5)The content of metakaolin is increased,and the fluidity of the polymer cement mortar is reduced;the amount of fly ash is increased,and the fluidity of the slurny is increased;When the amount of slag is increased,the fluidity of the slurny increases first and then decreases.When the content is 5%,the fluidity of the slurry reaches the maximum value of 151mm;The influence of mineral admixture on the fluidity of mortar is mainly due to its specific surface area and morphology.It is assumed that rheological parameters have a direct linear relationship.(6)The content of latex powder is between 1.5%and 2.5%,and the tensile adhesive strength increases with the increase of the amount;the tensile adhesive strength increases first and then decreases with the increase of the cellulose ether content.When the amount is 0.3%,the original strength of the stretched adhesive reaches a maximum value of 1.251 MPa,and when the amount is 0.4%,the tensile adhesive strength reaches a maximum value of 0.871 MPa when immersed in water.The coupling agent to the polymer cement mortar tensile adhesive strength.There is a clear lifting effect,which has little effect on the tensile adhesive strength after water immersion.After the polymer cement mortar is immersed in water,the tensile adhesive strength is always less than the tensile adhesive strength.