Study On The Formation And Macrodyna Micsof Carboniferous Silicalite In Cement-based Materials Under The Action Of Sulfate

Sulfate erosion has been a problem for a long time.Especially in sulfate attack,Thaumasite from of sulfate attack(TSA)occurs under low temperature,humidity,sulfate and carbonate conditions.The erosion will cause cement-based materials to expand,disintegrate and soften into slud-like substances.However,Xinjiang contains a large amount of saline soil rich in sulfate and chlorine salts,and the duration of low temperature in winter is longer in Xinjiang.Therefore,compared with other areas,carbonate sulphurite sulfate erosion is very easy to occur.In China,the research time on carbatisilonite is not very long,and there is no consensus on the occurrence mechanism,prevention mechanism and quantitative analysis of carbatisilonite,and the research method is relatively simple,and the total immersion method is basically adopted.Therefore,it is necessary to characterize and analyze the erosion process of cement-based materials through multi-factor tests for complex carbonate sulphurite sulfate erosion,and to conduct quantitative analysis of carbonate sulphurite in cement-based materials by internal standard Rietveld method.In this paper,TSA of cement-based materials is studied and elaborated mainly through different soaking methods,different erosion solutions,different erosion temperatures,and different dosage of limestone powder.The deterioration law of cementbased materials was characterized by the macroscopic mechanical properties of cementbased materials under different ages of sulfate erosion,such as flexural resistance,compressive resistance,tensile resistance and relative dynamic elastic modulus.Raman spectral analysis,X-ray diffraction(XRD)and internal standard Rietveld refinement were also adopted.A set of rapid quantitative analysis methods for fast carbosylsiloxalite in cement-based materials has been established,which solves the problems of accurate quantification in cement-based materials containing multi-phase and multi-overlapping peaks,and improves the accuracy of quantitative study of each phase in cement-based materials.Full immersion cement base material in the process of erosion than half soaking cement base material erosion mechanism is relatively simple,full soaking cement mortar in the whole process of erosion due to prolonged late coupling the cement hydration and sulphate erosion chemical reaction,mechanical performance presents the trend of volatility,and half in the process of erosion due to the different soaking mortar erosion,erosion of medium temperature,The mechanical properties of different parts of mortar show different deterioration rules.As for the local damage degradation law of mortar sand specimen formed by semi-immersion under different erosion conditions with time,the tensile test and statistical multivariate logistic regression analysis show that under the influence of time effect,the change of mortar fracture position in the tensile process of the specimen soaked in 15%Mg SO4 solution has a significant influence on the temperature.The mechanism of liquid level rise caused by capillary action of semi-immersed pure slurry in different temperature and erosion media was explored and elaborated,and the Rietveld quantitative analysis of the erosion products at different upper and lower parts of the pure slurry was carried out.It was found that chemical sulfate erosion occurred at the upper and lower parts of the pure slurry in the semi-immersed 15% sodium sulfate solution.For the net slurry soaked in 15% magnesium sulfate solution,only the lower part of the chemical sulfate erosion occurred,and for the net slurry soaked in 0.3 water cement ratio and 16% gypsum cement,a large number of carbonosilicate was found in the erosion of 23 months,in contrast,exogenous sulfate can promote the occurrence of carbonosilicate.By Rietveld quantitative analysis of carbosilicate in cement slurry soaked in different erosion solutions at different temperatures,the macroscopic kinetics of carbosilicate was calculated from the relationship between carbonate conversion rate and reaction time,and the comprehensive apparent rate of formation and apparent activation energy of carbosilicate in different solutions were obtained.