Ba ions are known to immobilise sulfates by forming BaSO4. The use of BaCO3 as a full or partial substitute for gypsum to regulate C3A (3CaO·Al2O3) hydration was consequently studied with a view to establishing its correct dosage in sulfate-resistant cements presently under development.\ud\udThe hydration rate of synthetic C3A was determined in the presence of varying percentages of gypsum, BaCO3, and gypsum + BaCO3 by running conduction calorimetry analyses on early age (up to 20 h) samples. The hydration products were subsequently identified with XRD, FTIR and DTA/TG.\ud\udThe addition of (20–42 wt.%) BaCO3 to C3A neither regulated the speedy reaction of the latter with water nor reacted with the aluminate. Gypsum + BaCO3 blends proved able to regulate C3A hydration; the heat flow curves for the mixes studied exhibited an induction period, an indication that gypsum acted as a C3A hydration regulator whilst at the same time reacting with BaCO3 to form barite.
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机译：已知Ba离子通过形成BaSO4固定硫酸盐。因此，研究了使用BaCO3作为石膏的全部或部分替代品来调节C3A（3CaO·Al2O3）的水合作用，以期确定其在目前正在开发的耐硫酸盐水泥中的正确用量。\ ud \ ud合成C3A的水合速率通过在早期样品（长达20小时）中运行传导量热分析，在存在不同百分比的石膏，BaCO3和石膏+ BaCO3的情况下测定碳含量。随后用XRD，FTIR和DTA / TG鉴定水合产物。\ ud \ ud向C3A中添加（20-42 wt。％）BaCO3既不能调节后者与水的快速反应，也不能与铝酸盐反应。石膏+ BaCO3混合物被证明能够调节C3A的水合作用。所研究混合物的热流曲线显示出诱导期，表明石膏充当C3A水化调节剂，同时与BaCO3反应形成重晶石。
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