Corrosion Law And Microstructure Evolution Of Cement Mortar Submitted To Sulfuric Acid And Citric Acids

A lot of concrete and gel material used in wastewater treatment system.For a lot of infrastructure,the microorganisms in the wastewater can form a corrosive solution,which could damage gelled material,reduce the service life of materials.In the sewage environment,sewage disposal concrete structures subject to various kinds of acid,alkali,organic matter,inorganic matter and microbial corrosion,mechanical impact and abrasion,and the effect of climatic factors,the corrosion mechanism is extremely complex,involve the biological sciences,chemistry,material science,water treatment science and structural engineering,and other fields,is a cross discipline.This topic mainly studied the corrosion of acid on the corrosion mechanism of cement mortar and cement slurry in sewage.Using chemical sulfuric acid and citric acid to simulate the accelerated process of corrosion,special experiment was designed,and typical concrete acid corrosion environment was simulated.Under different environment,corrosion of acid for cement mortar and cement slurry and the relevant conclusions was studied.First,the change of mass and strength during the corrosion process was studied,and the corrosion.The quality evolution of acid corrosion was determined,and the corrosion products were analyzed by SEM and XRD.Secondly,through the chemical reaction kinetics principle,the chemical reaction series is determined and analyzed.Secondly,through the chemical reaction kinetics principle,the chemical reaction series is determined and analyzed,the calculation model of porosity change of cement stone in acid corrosion environment was established.In the same temperature,the higher the concentration of acid,the higher the concentration of acid,the higher the concentration of the sample,the higher the temperature,increase the chemical activity of the reaction substance,so that the reaction is more rapid and the reaction is also deeper,Corrosion is more likely to occur,which means that the temperature rise can promote the conduct of this corrosion reaction.Sulfuric acid corrosion products under the scanning electron microscope were thin rods of calcium sulfate whiskers,citric acid corrosion products were short rods of calcium citrate.The chemical reactions of two kinds of acid corrosion were determined as the first order reaction,and the activation energies were 32.6kJ/mol and 15.3kJ/mol,respectively.The first-order reaction rate equation λ=a’(1-e-tltb) was used to characterize the mass evolution of mortar after acid corrosion,and the parameters ’a and tb of sulfuric acid and citric acid at different temperatures and different concentrations were determined.Based on the chemical reaction model of sulfuric acid-eroded concrete,the erosion of cement was compared and analyzed.The calculation model of porosity change of cement under the corrosion of sulfuric acid and citric acid was established.In the sewage environment,the corrosion of concrete is more complex,chemical and biochemical interaction results.Therefore,a single acid corrosion test can not completely simulate the sewage environment of concrete corrosion.