Aluminate containing phases such as tricalcium aluminate (C₃A) and dodecacalcium heptaaluminate (C₁₂A₇) play a key role in the reaction between Portland cement and cellulose ether. In order to simplify such impact from calcium aluminate, calcium aluminate cement (CAC) was applied as a carrier. Effects of hydroxyethyl methyl cellulose ether (HEMC) on the hydration of CAC were characterized by means of isothermal calorimetry, X-ray diffraction analysis, thermal analysis and scanning electron microscopy, respectively. Meanwhile, the setting times, water retention, air content and compressive strengths of HEMC modified CAC pastes or mortars were also determined. Results indicate that HEMC prominently delays the hydration of CAC within 1 day, and the higher dosage of HEMC, the longer setting times. HEMC exerts no obvious impact on the formation amount of CAH₁₀, only leads to a smaller crystal size. From aspect of physical and mechanical properties, the addition of HEMC improves the water retention of fresh CAC mortars, and only with addition of 0.1% HEMC, the water retention of fresh CAC mortars almost approaches 100%. Additionally, the addition of HEMC also significantly promotes the air content of fresh CAC mortars, leading to an obvious decrease in the compressive strengths.

中文翻译：

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羟乙基甲基纤维素醚对铝酸钙水泥水化和抗压强度的影响

含铝酸盐的相，例如铝酸三钙（C ₃ A）和十二铝酸七铝酸盐（C ₁₂ A ₇）在波特兰水泥与纤维素醚之间的反应中起关键作用。为了简化这种对铝酸钙的影响，铝酸钙水泥（CAC）被用作载体。通过等温量热法，X射线衍射分析，热分析和扫描电子显微镜分别表征了羟乙基甲基纤维素醚（HEMC）对CAC水合的影响。同时，还测定了HEMC改性的CAC糊或砂浆的凝结时间，保水率，空气含量和抗压强度。结果表明，HEMC在1天内显着延迟了CAC的水合作用，HEMC的剂量越高，凝结时间越长。HEMC对CAH ₁₀的形成量没有明显影响，只会导致较小的晶体尺寸。从物理和机械性能的角度来看，加入HEMC可以改善新鲜CAC砂浆的保水性，仅加入0.1％HEMC，新鲜CAC砂浆的保水率就接近100％。此外，加入HEMC还可以显着提高新鲜CAC砂浆的空气含量，从而导致抗压强度明显降低。