Use of Different Barium Salts to Inhibit the Thaumasite Form of Sulfate Attack in Cement-based Materials
来源期刊：Journal Of Wuhan University Of Technology Materials Science Edition2016年第2期
论文作者：苏英 WEI Xiaochao 黄健 WANG Yingbin HE Xingyang WANG Xiongjue MA Baoguo
文章页码：361 - 366
摘 要：We investigated the effects of different barium compounds on the thaumasite form of sulphate attack（TSA）resistance of cement-based materials when they were used as admixtures in mortars.Moreover,we analyzed the inhibition mechanisms within different types of barium salts,namely BaCO3 and Ba（OH）2,on the thaumasite formation.The controlcement mortar and mortars with barium salts to cement and limestone weight ratios of 0.5%,1.0%,and 1.5% were immersed in 5%（by weight）MgSO4 solution at 5 ℃ to mimic TSA.Appearance,mass,and compressive strength of the mortar samples were monitored and measured to assess the generaldegradation extent of these samples.The products of sulphate attack were further analyzed by XRD,FTIR,and SEM,respectively.Experimentalresults show that different degradation extent is evident in allmortars cured in MgSO4 solution.However,barium salts can greatly inhibit such degradation.Barium in hydroxide form has better effectiveness in protection against TSA than carbonate form,which may be due to their solubility difference in alkaline cement pore solution,and the presence of these barium compounds can reduce the degree of TSA by comparison with the almost completely decomposed controlsamples.
苏英1，WEI Xiaochao1，黄健2，WANG Yingbin1，HE Xingyang1，WANG Xiongjue1，MA Baoguo2
1. School of Civil Engineering and Architecture,Hubei University of Technology2. State Key Laboratory of Silicate Materials for Architectures,Wuhan University of Technology
摘 要：We investigated the effects of different barium compounds on the thaumasite form of sulphate attack（TSA）resistance of cement-based materials when they were used as admixtures in mortars.Moreover,we analyzed the inhibition mechanisms within different types of barium salts,namely BaCO3 and Ba（OH）2,on the thaumasite formation.The controlcement mortar and mortars with barium salts to cement and limestone weight ratios of 0.5%,1.0%,and 1.5% were immersed in 5%（by weight）MgSO4 solution at 5 ℃ to mimic TSA.Appearance,mass,and compressive strength of the mortar samples were monitored and measured to assess the generaldegradation extent of these samples.The products of sulphate attack were further analyzed by XRD,FTIR,and SEM,respectively.Experimentalresults show that different degradation extent is evident in allmortars cured in MgSO4 solution.However,barium salts can greatly inhibit such degradation.Barium in hydroxide form has better effectiveness in protection against TSA than carbonate form,which may be due to their solubility difference in alkaline cement pore solution,and the presence of these barium compounds can reduce the degree of TSA by comparison with the almost completely decomposed controlsamples.
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