在氧化镁微膨胀水泥中掺入不同数量的粉煤灰,通过测定净浆膨胀以及分析水化产物和水泥石微结构,研究了粉煤灰对氧化镁微膨胀水泥膨胀性能的影响及其机制.结果表明:随着粉煤灰掺量的增加,水泥膨胀率减小,在掺量大于20%时,氧化镁膨胀几乎完全被抑制;粉煤灰使水泥石孔隙率增加、平均孔径降低,并分布大量的玻璃微珠;粉煤灰使水泥水化产物中CH减少.粉煤灰对氧化镁微膨胀水泥的膨胀性能的抑制作用,与粉煤灰使水泥石中细孔和玻璃微珠增加、水化产物中CH减少是一致的.为了更好理解粉煤灰对膨胀性能的影响机制,还提出了膨胀场理论.
The effects of fly ash on the expansive property of MgO expansive cement were investigated by determining expansion, analyzing hydrated products and pore structure of cement paste, and then the mechanism was also discussed. MgO expansion is restrained greatly by fly ash, almost completely restrained if the content of fly ash is over 20%. Fly ash provides a lot of "glass balls" embed in the cement paste, which increases porosity with a smaller average diameter and decreases CH content in hydrated products. The inhibiting effect of fly ash on expansion is in agreement with its effects on the microstructure of hydrated paste. To explain the effect, a hypothesis "expansive field" was suggested.
参考文献
| [1] | 楼宗汉,叶青,陈胡星,王宇清,沈锦林.水泥熟料中氧化镁的水化和膨胀性能[J].硅酸盐学报,1998(04):430-436. |
| [2] | 陈胡星,李东旭,叶青,王宇青,楼宗汉.钙矾石与方镁石双膨胀作用研究[J].硅酸盐学报,2000(Z1):1-5. |
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