硫酸钠侵蚀对蒸养粉煤灰水泥石氯离子固化性能的影响
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摘要
采用等温吸附平衡法,并借助X射线衍射仪,研究了硫酸钠腐蚀溶液对蒸养条件下不同静养时间水泥石中固化态氯离子稳定性的影响。结果表明:固化态氯离子在硫酸钠溶液腐蚀环境下易失去稳定性,重新转变成游离态;标准养护条件下水泥石固化氯离子能力以及水泥石中固化态氯离子耐硫酸盐腐蚀能力均高于蒸汽养护条件下;掺加粉煤灰会有效提高水泥石固化氯离子的能力,但对硫酸盐环境下水泥石中固化态氯离子的稳定性存在一定程度的负面影响;静养时间4 h时,水泥石氯离子固化性能最优,静养时间6 h时,水泥石中固化态氯离子的稳定性较好。
The adsorption equilibrium method and X-ray diffraction was used to study the effect of sodium sulfate solution for the stability of bounded chloride in harden cement paste( HCP) under different curing conditions. The results show that the stability of bound chloride ions is very susceptible to Na2 SO4 attack,which lead to the transformation of chloride from bound state to free state. The chloride binding capacity of HCP and the resistance of bounded chloride ions face to sulfate corrosion under standard curing conditions is higher than that under steam curing conditions. The addition of fly ash can effectively improve the chloride binding capacity of HCP,but it will lead to negative impact for the stability of the bounded chloride ions under the sulfate environment; the best delay time for HCP to bounded chloride ions is 4 h,and for the stability of bounded chloride ions,the delay time is 6 h.
The adsorption equilibrium method and X-ray diffraction was used to study the effect of sodium sulfate solution for the stability of bounded chloride in harden cement paste( HCP) under different curing conditions. The results show that the stability of bound chloride ions is very susceptible to Na2 SO4 attack,which lead to the transformation of chloride from bound state to free state. The chloride binding capacity of HCP and the resistance of bounded chloride ions face to sulfate corrosion under standard curing conditions is higher than that under steam curing conditions. The addition of fly ash can effectively improve the chloride binding capacity of HCP,but it will lead to negative impact for the stability of the bounded chloride ions under the sulfate environment; the best delay time for HCP to bounded chloride ions is 4 h,and for the stability of bounded chloride ions,the delay time is 6 h.
引文
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[15]胡红梅,马保国.矿物功能材料的Cl-结合能力[J].建筑材料学报,2004,7(4):406-410.
[2]王绍东,黄煜镔,王智.水泥组分对混凝土固化氯离子能力的影响[J].硅酸盐学报,2000,28(6):570-574.
[3]黎鹏平,苏达根,王胜年,等.水泥中S/Al和外渗硫酸盐对氯离子临界浓度的影响[J].华南理工大学学报:自然科学版,2010,38(9):80-84.
[4]耿健,杨海明,莫立伟.硫酸钠溶液腐蚀对固化态氯离子稳定性的影响[J].建筑材料学报,2015,18(6):919-925.
[5]管斌君,耿健.水泥中固化态氯离子在硫酸盐腐蚀环境中变化特征[J].硅酸盐通报,2015,34(3):824-828.
[6] Xu J,Zhang C,Jiang L,et al. Releases of bound chlorides from chloride-admixed plain and blended cement pastes subjected to sulfate attacks[J]. Construction and Building Materials,2013,45:53-59.
[7] Brown P W,Badger S. The distributions of bound sulfate and chlorides in concrete subjected to mixed Na Cl,Mg SO4,Na2SO4attack[J].Cement&Concrete Composites,2000,30(10):1535-1542.
[8]潘冬冬,李东,毛荣一,等.蒸养下矿渣微粉对水泥基材料氯离子固化特性研究[J].矿冶,2017,26(3):87-90.
[9] Thomas M D A,Hooton D,Scott A,et al. The effect of supplementary cementitious materials on chloride binding in hardened cement paste[J].Cem. Concr. Res.,2012,42(1):1-7
[10] Tang L,Nilsson L O. Chloride binding capacity and binding isotherms of OPC pastes and mortars[J]. Cement and Concrete Research,1993,23(2):247-253.
[11] Ipavec A,Vuk T,Gabrovsek R. Chloride binding into hydrated blended cements:the influence of limestone and alkalinity[J]. Cement and Concrete Research,2013,48:74-85.
[12]毛荣一,耿健,李鹏鹏,等.蒸养静停时间对标养水泥石氯离子固化性能的影响[J].硅酸盐通报,2017,36(7):2215-2219.
[13] Tritthart T J. The influence of the hydroxide concentration in the pore solution of hardened cement paste on chloride binding[J]. Cement and Concrete Research,1989,19(5):683-691.
[14]马保国,李相国,王信刚,等.粉煤灰的形态效应与氯离子吸附固化特性[C].Ⅱ中国硅酸盐学会混凝土水泥制品分会第七届理事会议暨学术交流大会.北京:中国硅酸盐学会,2005:284-288.
[15]胡红梅,马保国.矿物功能材料的Cl-结合能力[J].建筑材料学报,2004,7(4):406-410.