ABSTRACT

In this investigation, it was studied the effect of curing temperature on the mechanical properties of pastes made with calcium sulfoaluminate cements synthesised from industrial wastes at a relatively low temperature of 1100°C. Fluorgypsum, fly ash, aluminium slag and calcium carbonate were used as raw materials. The main phases of synthesis were calcium sulfoaluminate and gehlenite. Pastes were prepared with different water/cement ratios, 15–25 wt-% hemihydrate and cured at 20 and 40°C. It was found that with higher total amounts of sulphates and increase in temperature, compressive strength is enhanced in the first days of curing and setting times decreased. Ettringite was found to be the main reaction product forming dense structures over time. Calcium sulphates hydration changed the ettringite formation causing fluctuations in the strength development, nevertheless, in some cases the strength surpassed 40 MPa at 28 days. Microstructures and hydration products were studied by SEM and XRD.

摘要

在这项调查中，研究了固化温度对用工业废料合成的硫铝酸钙水泥在 1100°C 的相对较低温度下制成的糊状物的机械性能的影响。以氟石膏、粉煤灰、铝渣和碳酸钙为原料。合成的主要阶段是硫铝酸钙和钙黄长石。用不同的水/水泥比例制备糊状物，15-25wt% 的半水合物，并在 20 和 40°C 下固化。发现随着硫酸盐总量的增加和温度的升高，在固化的第一天抗压强度增强，固化时间减少。发现钙矾石是随时间形成致密结构的主要反应产物。硫酸钙水合改变了钙矾石的形成，导致强度发展出现波动，但在某些情况下，强度在 28 天时超过 40 MPa。通过SEM和XRD研究显微结构和水合产物。