Study On The Performance Of Cement Based Brine Against Sulfate Attack

There are a lot of Saline Lake in the northwest region of China.Saline soil contains much sulfate ion and chlorine,it can caused obvious damage to reinforced concrete and cement concrete,then make the mechanical property and durability of concrete degeneration,cause the service life shortened.Cement-based grouting material is a kind of dry-mixed material that is composed of cement(being its substrate material),proper amount of fine aggregate,other admixtures and additives.After mixing with water it has such characteristics such as high fluidity,early strength,high strength,and micro-expansion.In this paper,based on the particular environment of a northwest lake district and requirements of the construction,we selected sulfur aluminate cement and ordinary portland cement separately.For test water,and conservative water,we selected the running water from Xi'an city and brine water that is of high salt,mixed with fly ash,expansive and polycarboxylate.According to the orthogonal experiment,we intend to formulate a new kind of cement-based grouting material.This material will grout through the pressure of the middle pipe,and the slurry will cover the surface of the concrete pile body from below under pressure,clogging the pores inside the concrete,prevent the concrete inside from the hazardous substances,thus protecting the concrete structures.Finally provide some information and advice for engineering application.Via orthogonal experiment scheme.Though the mechanical properties of cement based grouting material by the erosion of the brine,this paper analyzes the influence of type of cement,water,water cementing material ratio,cement-sand ratio,flyash amount,naphthalene superplasticizer,and swelling agent on the fluidity,the rupture streng and compression strength of cement based grouting material,and the difference of corrosion resistance In different situations by using room temperature water.And reaching conclusions as follows:1)After proper ratio,the initial flow of grounting material is mostly above 300mm.1)With some modified measures,confecting a new type of cement based grouting material mainly uses ordinary portland cement as ingredient,which performances better than sulphur-aluminate-based cement in certain requirements on the performance.3)With ordinary cement as raw material,we get the sulfate resistant cement slurrywhose initial fluidity is 345mm,3d compress strength close to 43 MPa,28d strength close to 69 MPa and the age of resistance coefficient was above 0.9 when water to binder ratio of 0.3 5,fly ash mixing capacity is 15%,the expansive agent dosage is 10%,polycarboxyl ate supe rpl-asticizer content in 1.3%and cement sand ratio control in 1:1?4)After the durability test,the new water machine base grouting material for resisting sulf-ate attackcan reach more than 125 times,and the corrosion resistance coefficient is still mo-re than 0.75 after 30 times of Sulfate resistance and anti seawater wet dry cycle.