Preparation And Performance Research Of Sulfate-corrosion Resistance Preservative

Concrete corrosion protection material has outstanding effect on prolonging its service life and improving its structure and performance.Looking for cement based materials preservative with good performance is a hot spot in engineering application in recent years.In this paper,on the basis of the research on the MK-cement performance,A MK based mortar concrete sulfate erosion preservative was developed,and its sulfate attack resistance of concrete are studied.Paper's main work and achievements are as follows:1 MK can accelerate cement condensation sclerosis,increase mortar consistency,improve the mechanical performance of mortar,decrease the permeability of mortar,reduce mortar drying shrinkage and raise the resistance to sulfate erosion,it is a kind of good mineral admixture to promote the durability of cement based material,and its best dosage of is around 8%.2.Through the study on the corrosion resistance of different chemical additives,the research find that calcium stearate,barium carbonate,lithium carbonate,sodium citrate,latex powder and defoaming agent can improve the resistance performance to sulfate erosion of cement based material;the calcium stearate,lithium carbonate and barium carbonate has small impact on other aspects of the performance of cement based material and are suitable for used as a preservative;sodium citrate has detrimental influence on the condensation of cement-based materials,and latex powder greatly decrease the mechanical properties of cement based material.These two kinds of chemical additives is not suitable for use as a component of preservatives.Adding defoaming agent for cement based material can also improved cement baesd material's sulfate erosion resistance.3.Orthogonal experiment results showed that the optimal proportion for the preparation of sulfate erosion resistancer are:MK content around 8%,about 1.0%dosage of BaCO₃,calcium stearate content around 0.5%,about 0.01%dosage of li₂CO₃.4.The sulfate corrosion resistance manufactured from this study show a good performance of resistance to sulfate erosion on concrete,it can be used as reliable cement based material admixture for ther resistance to sulfate erosion,and after coupling with fly ash the performance is better.5.Each preservative components's sulfate erosion resistance mechanism in cement base material according to this study of are:BaCO₃'canwork with SO₄^2–to form a highly insolubility salt BaSO₄,the reaction thus inhibit the growth of ettringite?AFt?and CaSO₄.Li₂CO₃ can inhibit the ettringite formation in the cement,promote cement CaSO₄'s transform to low dilatability product,therefore can improve the resistance to sulfate attack of cement performance.Calcium stearate's can inhibit the Ca?OH?₂ precipitate,hinder the intrusion of SO₄^2-in the cement and its following reaction with Ca?OH?₂,thus reducing the formation of ettringite and CaSO₄.Due to its reaction with part of Ca?OH?₂,MK can improve the resistance to sulfate erosion performance of cement by greatly reduce the poor erosion resistance content of Ca?OH?₂.