本文研究粉煤灰对ASR的抑制作用.测定了不同粉煤灰掺量砂浆棒膨胀率、水泥石中Ca(OH)2含量以及主要水化产物C-S-H凝胶的微观结构和化学组成,并对粉煤灰抑制ASR的机制进行探讨.结果表明:随粉煤灰掺量增加,其对ASR具有显著的抑制效果.水泥石中Ca(OH)2含量不断减少,二次反应生成大量低n(Ca)/n(Si)的C-S-H凝胶.随n(Ca)/n(Si)降低,C-S-H凝胶中固溶了大量的Al,凝胶的固碱能力增强,从而使混凝土孔溶液中的有效碱大大减少,减轻了ASR程度.凝胶的固碱能力增强除了因n(Ca)/n(Si)降低,使C-S-H凝胶的固碱能力增强之外.还可能因为Al3+代替Si4+形成[AlO4]5-四面体,由于Al3+比Si4+少一价,引起电价不平衡,系统带负电,因此碱离子更容易进入C-S-H凝胶中,减少了碱与活性集料反应的机会.
参考文献
| [1] | M A BERUBE;B FOURNIER;B DURAND.Proceedings of 11 International Conference on AAR in Concrete[M].Québec City.Canada:[s.n.],2000:Ⅲ-Ⅳ. |
| [2] | 封孝信,冯乃谦.天然沸石对碱-硅酸反应的抑制及其机理[J].硅酸盐学报,2002(06):669-674. |
| [3] | P J Nixon et al.The effect of a pfa with a high total alkali content on pore solution composition and alkali silica reaction[J].Magazine of Concrete Research,1986,38:30-50. |
| [4] | V S Ramachandram;黄士元.混凝土科学[M].北京:中国建筑工业出版社,1986 |
| [5] | Medhat H. Shehata;Michael D.A. Thomas .Use of ternary blends containing silica fume and fly ash to suppress expansion due to alkali - silica reaction in concrete[J].Cement and Concrete Research,2002(3):341-349. |
| [6] | M H Shehata .The Effects of Fly Ash and Silica Fume on Alkali silica Reaction in Concrete[D].University of Toronto,2001. |
| [7] | M H Shehata;M D A Thomas .The effects of fly ash composition on the expansion of concrete due to alkali-silica reaction[J].Cement and Concrete Research,2000,30:1063-1072. |
| [8] | Sung-Yoon Hong;F P Glasser .Alkali binding in cement pastes part Ⅰ.The C-S-H phase[J].Cement and Concrete Research,1999,29:1893-1903. |
| [9] | 杨忠义.硅灰对碱-硅反应及膨胀的抑制机理[J].水电站设计,2000(02):105-110,112. |
| [10] | P Faucon;A Delagrave;J C Petit et al.Aluminum Incorporation in Calcium Silicate Hydrates (C-S-H) Depending on Their Ca/Si Ratio[J].Journal of Physical Chemistry B,1999,103:7796-7802. |
| [11] | I G Richardson;A R Brough;R Brydson et al.Substituted Calcium Silicate Hydrate (C-S-H) Gels as Determined by 29Si and 27Al NMR and EELS[J].Journal of the American Ceramic Society,1993,76:2285-2288. |
| [12] | 南京化工大学材料科学与工程系.硅质集料碱活性试验方法一中国快速砂浆棒法[M].,1998 |
| [13] | Digest 330, Part 2: Alkali silica reaction in concrete, detailed guideline for new construction[S].,1997. |
| [14] | S Y Hong;F P Glasser .Alakli sorption by C-S-H and C-A-S-H gels part Ⅱ , Role of alumina[J].Cement and Concrete Research,2002,2:1101-111. |
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