煅烧保温时间对 CMA 水泥水化和流变特性的影响

摘要

Two kinds of spinel containing calcium aluminates cements (CMA cements:CMA-3 and CMA-6 h) were synthesized using industrial alumina,light burnt magnesite and heavy weight calcium carbonate as starting materials,firing and soaking for 3 h and 6 h at 1 500 ℃,respectively.The phase composition and mi-crostructure were studied.The hydration and rheological behavior of CMA cement slurry were determined using Vicat apparatus and rheometer.The results show that:(1)the MA grain size of CMA-3 h cement is small,and CA crystals develop incompletely and disperse in the MA particles,the coagulating time of the ce-ment is short;the CMA-6 h cement has bigger MA crystals,CA crystals develop well,and the initial setting time of the cement accords with the service standard of aluminate cement;(2)the τ-γcurves of cement slur-ry are in accordance with Bingham fluid model;compared with CMA-3 h cement,CMA-6 h cement has smal-ler hydration degree and smaller flocculation strength;(3)during the cement slurry time scanning test,the ce-ment slurries storage modulus G′increases rapidly with the time prolonging and tends to be stable finally,and the increasing speed of G′of CMA-3 h cement is the fastest,indicating its hydration speed is the fastest.%为了研究煅烧保温时间对含镁铝尖晶石的铝酸盐水泥（CMA）的水化特性和流变特性的影响，选用工业氧化铝、轻烧镁砂、重质碳酸钙为原料，在1500℃分别保温3和6 h，制备了 CMA－3 h 和 CMA－6 h 两种 CMA 水泥，进行了物相组成和显微结构分析，使用维卡仪和流变仪测定了 CMA 水泥泥浆的水化和流变特性。结果表明：1）CMA－3 h 水泥的 MA 晶粒较小，CA 晶粒发育不完整，分散于 MA 颗粒之间，水泥凝结时间较短；CMA－6 h水泥的 MA 晶粒较大，CA 晶粒发育完整，水泥初凝时间符合铝酸盐水泥的使用标准。2）水泥浆体的τ－γ曲线符合宾汉流体模型；较之 CMA－3 h 水泥试样，CMA－6 h 的水化程度更小，絮凝强度较小。3）水泥净浆的时间扫描测试中，水泥净浆的储能模量 G′随时间增加而快速增加，然后趋于稳定，并且 CMA－3 h 水泥试样 G′增长速率更快，表明其水化速率更快。