浸水养护下混合水泥浆体孔溶液pH值对钢筋锈蚀的影响
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摘要
研究了粉煤灰和矿渣粉不同掺量对后期水泥浆体孔溶液p H值的影响,采用金属腐蚀原理-Pourbaix图法分析了混合水泥砂浆中钢筋锈蚀现象,探讨了浸水养护下浆体孔溶液p H值与钢筋锈蚀的关系。结果表明:水泥浆体孔溶液p H值随粉煤灰掺量增加而降低,当掺量为90%时,730 d浆体孔溶液p H值可降至8.5左右;矿渣粉水泥的浆体孔溶液p H值均保持在12以上;浆体孔溶液p H值低于12.2时,钢筋就会发生锈蚀,降至9以下时,钢筋锈蚀严重。
The effect of contents of fly ash and slag on the pH value of the cement paste pore solution was investigated. The corrosion phenomenon of different alkalinities cement mortars under water curing condition was analyzed based on the principles of electrochemistry of corrosion-pourbaix figure. The correlation between the pH value and corrosion-resistance was discussed. The results show that the pH value of fly ash cement paste pore solution reduces with the increase of fly ash content, when the content of fly ash in blended cement is up to 90%, the pH value drops to 8.5 at 730 d. When the pH value is < 12.2, the steel in mortar corrodes slightly. When the pH value of the paste pore solution is < 9, the steel in the mortar corrodes seriously.
The effect of contents of fly ash and slag on the pH value of the cement paste pore solution was investigated. The corrosion phenomenon of different alkalinities cement mortars under water curing condition was analyzed based on the principles of electrochemistry of corrosion-pourbaix figure. The correlation between the pH value and corrosion-resistance was discussed. The results show that the pH value of fly ash cement paste pore solution reduces with the increase of fly ash content, when the content of fly ash in blended cement is up to 90%, the pH value drops to 8.5 at 730 d. When the pH value is < 12.2, the steel in mortar corrodes slightly. When the pH value of the paste pore solution is < 9, the steel in the mortar corrodes seriously.
引文
[1]曹楚南.腐蚀电化学原理(第三版)[M].化学工业出版社,2008:18–26.
[2]曹楚南.金属电化学腐蚀基本原理(上)[J].冶金建筑,1981(5):50–53.Cao Chunan.Metall Construct,1981(5):50–53.
[3]SHEHATA M H,THOMAS M D A.Use of ternary blends containing silica fume and fly ash to suppress expanse ion due to alkali–silica reaction in concrete[J].Cem Concr Res,2002,32(3):341–349.
[4]DIAMOND S.Effects of two Danish fly ashes on alkali contents or pore solutions of cement–fly ash pastes[J].Cem Concr Res,1981(11):383–394.
[5]GLASSER F P,LUKE K,ANGUS M J.Modification of cement pore fluid compositions by pozzolanic additives[J].Cem Concr Res,1988,18(2):165–178.
[6]李响,阎培渝.粉煤灰掺量对水泥孔溶液碱度与微观结构的影响[J].建筑材料学报,2010,13(6):787–791.LI Xiang,YAN Peiyu.J Build Mater,2010,13(6):787–791.
[7]VERNET C,DéMOULIAN E,GOURDIN P,et al.Kinetics of slag cement hydration[C].7th International Congress on the Chemistry of Cement,III,1980:128–133.
[8]VERNET C.Comport cement de l'ion S–aucours de l'hydratation des ciments riche-en laitier(CLK)[J].Silicates Ind,1982(47):85–89.
[9]白常举.p H值与钢筋的锈蚀[J].混凝土及建筑构件.1982(3):23–26.BAI Changju.Concr Build Component,1982(3):23–26.
[10]BARNEYBACK R S,DIAMOD S.Expression and analysis of pore fluids from hardened cement pastes and mortars[J].Cem Concr Res,1981(1):279–285.
[11]董荣珍,卫军,张克强,等.钢筋锈蚀产物在界面处分布状态及成分[J].武汉理工大学学报.2008,30(3):67–69,78.DONG Rongzhen,WEI Jun,ZHANG Keqiang,et al.J Wuhan Univ Technol,2008,30(3):67–69,78.
[2]曹楚南.金属电化学腐蚀基本原理(上)[J].冶金建筑,1981(5):50–53.Cao Chunan.Metall Construct,1981(5):50–53.
[3]SHEHATA M H,THOMAS M D A.Use of ternary blends containing silica fume and fly ash to suppress expanse ion due to alkali–silica reaction in concrete[J].Cem Concr Res,2002,32(3):341–349.
[4]DIAMOND S.Effects of two Danish fly ashes on alkali contents or pore solutions of cement–fly ash pastes[J].Cem Concr Res,1981(11):383–394.
[5]GLASSER F P,LUKE K,ANGUS M J.Modification of cement pore fluid compositions by pozzolanic additives[J].Cem Concr Res,1988,18(2):165–178.
[6]李响,阎培渝.粉煤灰掺量对水泥孔溶液碱度与微观结构的影响[J].建筑材料学报,2010,13(6):787–791.LI Xiang,YAN Peiyu.J Build Mater,2010,13(6):787–791.
[7]VERNET C,DéMOULIAN E,GOURDIN P,et al.Kinetics of slag cement hydration[C].7th International Congress on the Chemistry of Cement,III,1980:128–133.
[8]VERNET C.Comport cement de l'ion S–aucours de l'hydratation des ciments riche-en laitier(CLK)[J].Silicates Ind,1982(47):85–89.
[9]白常举.p H值与钢筋的锈蚀[J].混凝土及建筑构件.1982(3):23–26.BAI Changju.Concr Build Component,1982(3):23–26.
[10]BARNEYBACK R S,DIAMOD S.Expression and analysis of pore fluids from hardened cement pastes and mortars[J].Cem Concr Res,1981(1):279–285.
[11]董荣珍,卫军,张克强,等.钢筋锈蚀产物在界面处分布状态及成分[J].武汉理工大学学报.2008,30(3):67–69,78.DONG Rongzhen,WEI Jun,ZHANG Keqiang,et al.J Wuhan Univ Technol,2008,30(3):67–69,78.