Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, School of Materials Science and Engineering, Tongji University, Shanghai 200092, China.
Waste Manag. 2012 Jul;32(7):1468-72. doi: 10.1016/j.wasman.2012.02.014. Epub 2012 Mar 21.
A series of novel mortars were developed from composite binder of uncalcined FGD gypsum, fly ash (FA) and ground granulated blast furnace slag (GGBFS) for the good utilization of flue gas desulphurization (FGD) gypsum. At a fixed ratio (20%) of GGBFS to the composite binder, keeping consistency of the mortar between 9.5 and 10.0 cm, the properties of the composite mortar were studied. The results show that higher water/binder (W/B) is required to keep the consistency when increasing the percentage of FGD gypsum. No obvious influences of the W/B and content of FGD gypsum on the bleeding of paste were observed which keeps lower than 2% under all experimental conditions tried. The highest compressive and flexural strengths (ratio is 20% FGD gypsum, 20% GGBFS and 60% FA) are 22.6 and 4.3 MPa at 28 days, respectively. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) results indicate that massive ettringite crystals and C-S-H gels exist in the hydration products. At 90 days the mortars with FGD gypsum is dramatically smaller drying shrinkage (563-938 micro strain) than that without FGD gypsum (about 2250 micro strain). The release of the SO(4)(2-) from the mortar was analyzed, indicating that the dissolution of sulfate increases with FGD gypsum. The concentration of SO(4)(2-) releasing from the mortar with 10% FGD gypsum is almost equal to that obtained from the mortar without FGD gypsum. The release of SO(4)(2-) from the mortar with 20% FGD gypsum is 9200 mg·m(-2), which is lower than that from the mortar with 95% cement clinker and 5% FGD gypsum.
一系列新型的砂浆是由未经煅烧的脱硫石膏、粉煤灰（FA）和磨细高炉矿渣（GGBFS）的复合胶凝材料开发的，旨在实现脱硫石膏的良好利用。在保持砂浆稠度为 9.5 到 10.0cm 的条件下，GGBFS 与复合胶凝材料的比例固定在 20%，研究了复合砂浆的性能。结果表明，随着脱硫石膏比例的增加，需要更高的水胶比（W/B）来保持稠度。在所有尝试的实验条件下，浆体的泌水率都保持在 2%以下，W/B 和脱硫石膏含量对其几乎没有明显影响。在 28 天时，抗压强度和抗折强度最高（20%脱硫石膏、20%GGBFS 和 60%FA）分别为 22.6MPa 和 4.3MPa。扫描电子显微镜（SEM）和 X 射线衍射（XRD）结果表明，水化产物中存在大量的钙矾石晶体和 C-S-H 凝胶。在 90 天时，掺有脱硫石膏的砂浆的干燥收缩率（563-938 微应变）明显小于未掺脱硫石膏的砂浆（约 2250 微应变）。分析了砂浆中 SO(4)(2-)的释放情况，表明硫酸盐的溶解随脱硫石膏的增加而增加。掺有 10%脱硫石膏的砂浆中 SO(4)(2-)的释放浓度几乎与不掺脱硫石膏的砂浆相同。掺有 20%脱硫石膏的砂浆中 SO(4)(2-)的释放量为 9200mg·m(-2)，低于掺有 95%水泥熟料和 5%脱硫石膏的砂浆。
