Laboratory of Waste Valorization and Sustainable Materials (ValoRes), Department of Civil Engineering, Federal University of Santa Catarina (UFSC), Florianópolis 88040900, Brazil.
Eduardo Torroja Institute, National Research Council (CSIC), 28033 Madrid, Spain.
Molecules. 2021 Mar 30;26(7):1938. doi: 10.3390/molecules26071938.
This work analyzes the effect of the presence of 5 wt.% of solid sodium salts (NaSO, NaCO, and NaSiO) on calcium sulfoaluminate cement (CSA) hydration, addresses hydration kinetics; 2-, 28-, and 90-d mechanical strength, and reaction product microstructure (with X-ray diffraction (XRD), and Fourier transform infrared spectroscopy, (FTIR). The findings show that the anions affect primarily the reactions involved. Ettringite and AH, are the majority hydration products, while monosulfates are absent in all of the samples. All three salts hasten CSA hydration and raise the amount of ettringite formed. NaSO induces cracking in the ≥28-d pastes due to post-hardening gypsum and ettringite formation from the excess SO present. Anhydrite dissolves more rapidly in the presence of NaCO, prompting carbonation. NaSiO raises compressive strength and exhibits strätlingite as one of its reaction products.
这项工作分析了 5wt%的固体钠盐（NaSO、NaCO 和 NaSiO）对钙矾石水泥（CSA）水化的影响，研究了水化动力学；2、28 和 90 天的机械强度，以及反应产物的微观结构（使用 X 射线衍射（XRD）和傅里叶变换红外光谱（FTIR））。研究结果表明，阴离子主要影响所涉及的反应。钙矾石和 AH3 是主要的水化产物，而所有样品中均不存在单硫酸盐。这三种盐都加速了 CSA 的水化，并增加了形成的钙矾石的量。由于存在过量的 SO，NaSO 会在 ≥28 天的浆体中引起开裂，形成后硬石膏和钙矾石。在 NaCO 的存在下，硬石膏溶解得更快，引发碳化。NaSiO 提高了抗压强度，并表现出 strätlingite 作为其反应产物之一。
