非晶态C12A7/CaSO4·2H2O体系对OPC早期性能的影响及作

关键字：非晶态C12A7,钙矾石,早强,水化

[1.中国矿业大学（北京） 化学与环境工程学院，混凝土与环境材料研究所，北京  100083；
2.中建材中岩科技有限公司，北京  100024]

    摘要：研究了5%掺量下，不同质量比的非晶态C12A7/CaSO4·2H2O体系对OPC净浆凝结时间、流动性和早期抗压强度的影响，通过XRD和SEM对水化产物的物相和形貌进行了表征。结果表明：非晶态C12A7/CaSO4·2H2O体系能够促进C3S和C2S的水化，生成C-S-H凝胶相互交织搭接形成网络结构而促进凝结；同时也促使OPC水化早期产生针状晶体钙矾石，钙矾石与前期生成的C-S-H凝胶相互填充，使水化产物结构密实，提高早期强度；当非晶态C12A7/CaSO4·2H2O体系掺量为5%，非晶态C12A7与CaSO4·2H2O的质量比为1.0∶1.0时，水泥早期强度最高，7 d抗压强度达到100 MPa，说明此体系反应比较完全。
    关键词：非晶态C12A7；钙矾石；早强；水化
    中图分类号：TU528.041        文献标识码：A        文章编号：1001-702X（2017）07-0104-04

Study on effects and mechanical performance of amorphous state C12A7/CaSO4·2H2O system on early properties of OPC
LI Wenping1，WANG Dongmin1，FAN Deke2，ZHANG Jiangtao1，WANG Yiren1
（1.Research Institute of Concrete and Eco-materials，School of Chemical & Environmental Engineering，China University of Mining & Technology，Beijing 100083，China；2.China Building Materials Science and Technology Co. Ltd，Beijing 100024，China）

    Abstract：This paper was to investigate that when the dosage of amorphous C12A7/CaSO4·2H2O system in OPC is 5%，the effect of different mass ratio of amorphous C12A7/CaSO4·2H2O system on setting time，mobility，early compressive strength of OPC. Physical phase and morphology of hydration products were characterized by XRD and SEM. The results showed that the system accelerated the hydration of C3S and C2S，the hydration product C-S-H gel intertwined overlap to form the network structure which resulted the quick setting of cement paste；it also formed a large amount of acicular ettringite，the structure of hydration products was more and more compact，because of the ettringite filled with C-S-H gel each other，it improved the early strength of cement paste；when the C12A7/CaSO4·2H2O system used 5% of unit weight of cement，the mass ratio of C12A7 and CaSO4·2H2O was 1.0 to 1.0，the early strength of OPC is the highest and the 7 d strength is 100 MPa，which shows that this system reacts completely.
    Key words：amorphous state C12A7，ettringite，early strength，hydration