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探讨了适量C_(11)A_7·CaF_2、C_4A_8显著提高粉煤灰水泥早期强度的机理。研究发现,适量C_(11)A_7·CaF_2、C_4A_8和石膏的掺入,使得在水泥水化早期就有较多的钙矾石生成,且A矿水化得以加速,所生成的钙矾石既形成网络结构又填补了水泥石中的孔洞和裂隙,以致粉煤灰水泥强度提高。实验表明,C_(11)A_7·CaF_2或C_4A_2的掺量为5wt%左右时,水泥凝结正常,强度提高幅度较大,可使粉煤灰水泥强度提高约1个标号,而当C_(11)A_7·CaF_2或C_4A_8掺量达10wt%以上时,水泥凝结急剧加速,水泥强度下降,掺入0.2wt%—0.3wt%柠檬酸可使水泥正常凝结。
The mechanism of the early strength improvement of fly ash cement was investigated by appropriate amounts of C_(11)A_7·CaF_2 and C_4A_8. The study found that the incorporation of appropriate amounts of C_(11)A_7·CaF_2, C_4A_8 and gypsum resulted in the formation of more ettringite in the early stage of cement hydration, and accelerated the hydration of A mineralization, resulting in the formation of ettringite. Both the network structure and the holes and crevices in the cement stone are filled so that the strength of the fly ash cement increases. Experiments show that when the content of C_(11)A_7·CaF_2 or C_4A_2 is about 5wt%, the cement coagulation is normal, the strength is increased greatly, and the strength of fly ash cement can be increased by about 1 label, and when C_(11) ) When the amount of A_7·CaF_2 or C_4A_8 yttrium exceeds 10% by weight, the cement concentration rapidly increases and the strength of the cement decreases. The addition of 0.2wt%-0.3wt% citric acid can cause the cement to condense normally.