石膏对硫铝酸盐水泥水化特性的影响

Impact of Calcium Sulfate on Hydration Features of Calcium Sulfoaluminate Cement

摘要:

研究了无水石膏及脱硫石膏对硫铝酸盐水泥抗压强度、干燥收缩率、早期水化放热及浆体组成的影响.结果表明：石膏能加速硫铝酸盐水泥的早期水化，低掺量（≤20%，质量分数）时1 d抗压强度提高，干燥收缩有所降低；随石膏掺量增加，3 d和28 d抗压强度先增后减；掺量过高时硬化浆体的后期强度甚至会倒缩；抗压强度与钙矾石生成量并无直接关联，与铝胶量成正相关.脱硫石膏可替代无水石膏配制出更优良的硫铝酸盐水泥，具有广阔前景.

Abstract:

The impact of calcium sulfate (anhydrite and desulphurization gypsum) on the hydration of calcium sulfoaluminate (CSA) cement, such as compressive strength, drying shrinkage ratio, hydration heat of early stage and microstructure evolution, was measured. Results reveal that, the early hydration of CSA cement is accelerated by the addition of calcium sulfate, resulting in higher 1day compressive strength and lower drying shrinkage once the dosage is less than 20% (mass ratio). However, with the increasing amount of calcium sulfate, 3day and 28day strength is prominently decreased, and even the retraction of strength happens when doping with excessive calcium sulfate. Compressive strength has no direct correlations with ettringite amount, while it has positive correlation with the alumina gel amount. Additionally, to achieve CSA cement with better properties, it is very promising to replace anhydrite with desulphurization gypsum.