Formation Of Tsa And Its Effect On Cement Hydration Reaction

Carbon-sulfuronite-type sulfate attack is a special sulfate attack(referred to as TSA).The damage form is very hidden,because it does not cause a significant volume change in the structure,but directly destroys the C-S-H gel in the cement stone,causing the structure to gradually become white and mud-like,non-cementing material,which destroys the structure.It’s huge,so it’s a huge loss to the structure.Because of the similarity in microstructure and chemical composition of ettringite and ettringite,early researchers mistakenly believed that ettringite-type failure sulfate destruction was a type of ettringite-type,but with the gradual dedestruction examples gradually With the increase,carbon-sulfuronite-type sulfate attack has become one of the research hotspots of many scholars.Carbionite is usuall formed easily under low tempeature,sufficient sulfate,carbonate ion and other conditions.Combined with the climatic characteristics of Xinjiang in the saline soil area and low winter temperature,it provides favorable conditions for carbon,sulfur,wollastonite type sulfate erosion.For this reason,the research in this paper has certain positive significance.Carbon-sulfuronite type erosion mainly destroys the CSH gel in cement stone,causing gradual destruction of the structure,and the hydration process of cement will generate a large number of CSH gels.Therefore,the formation of carbon-sulfuronite was investigated to cement hydration The impact of the response is significant.This article is mainly divided into two parts for research.The first half mainly accelerates the formation of carbosulfurite in experiments,and studies the influence of three different factors(water-to-gel ratio,the amount of dihydrate gypsum,the amount of magnesium sulfate,etc)on the formation of carbosulfurite.The second half mainly studies the influence of the formation of carbon-sulfuronite on the hydration reaction of cement from aspects of appearance change,quality change rate,compressive strength,chemically combined water and cement hydration kinetic model.The main contents and conclusions of the study are as follows:(1)Cement paste test blocks were prepared according to the specifications.Through the use of X-ray diffraction(XRD)qualitative analysis,relative content(semi-quantitative)analysis,and K-value method combined with chemical method,the quantitative analysis method was studied.The effect of the amount of gypsum and different amounts of magnesium sulfate on the content of caraformite is as follows: As the water-binder ratio increases,the content of carbaformite decreases gradually.When the water-to-gel ratio is 0.4,it is most beneficial to the formation of carbon-sulfuronite;the destruction effect of three kinds of content of different gypsum on carbon-sulfonite-type sulfate attack is from strong to weak:16% content> 10 % Dosing amount> 4% dosing amount;three kinds of doped magnesium sulfate content have a destructive effect on the carbasulfurite sulfate attack: 16% dosing amount> 10% dosing amount> 4% dosing amount.(2)Characterize the effect of the formation of carbon-sulfuronite on the hydration reaction of the cement from the aspects of the appearance change,quality change rate,compressive strength,chemically bound water and kinetic model of cement hydration reaction.The following conclusions were reached:The trend of the mass change rate of the test piece with a water-to-gel ratio of 0.4 is significantly larger than that of the test piece with a water-to-gel ratio of 0.3;with the increase of the content of carbasite,the degree of appearance damage of the sample is gradually increasing,and the resistance of the test piece is gradually increased.The compressive strength shows a downward trend;the chemically bound water content in the specimen gradually increases,so that the overall hydration of the cement in the cement-based material is higher;the kinetic rate of the cement hydration process in the cement-based material is compared: I> D> NG,that is,the formation of carbon-sulfuronite has the greatest influence on the I process of cement hydration reaction.In this paper,a combination of qualitative and quantitative,macro and micro research methods are used to thoroughly investigate the influence of different factors on the wollastonite and the effect of TSA on the hydration kinetics of cement.The study on the erosion of TSA provides a certain theoretical basis.