高铝水泥对脱硫建筑石膏的改性研究

Research on the modification of FDG building gypsum with high alumina cement

研究了高铝水泥对脱硫建筑石膏的标准稠度用水量、凝结时间及力学性能的影响,并结合复合胶凝材料的微观结构进行了机理分析。试验结果表明:高铝水泥的添加减小了脱硫建筑石膏的标准稠度用水量,延长了凝结时间,并且提高了试件的力学性能和耐水性。当掺量为20%时,试件的28 d抗折、抗压强度分别为6.03、11.05 MPa,比纯石膏提高了99.67%和80.56%,软化系数达0.70,比纯石膏提高了59.09%。通过微观表征可知,掺入高铝水泥后,石膏晶体表面生成了强度高且不溶于水的C-S-H凝胶和钙矾石,这是高铝水泥能提高脱硫建筑石膏力学强度和耐水性的原因。

The effect of high alumina cement to FGD building gypsum on water requirement of normal consistency, setting time and mechanical properties was investigated. The mechanism was also discussed with the microstructure of cementing materials. The test showed that the high alumiria cement can reduce water requirement of normal consistency of FGD building gypsum, extend the setting time and improve the mechanical properties and water resistance of the sample. When the content of the high alumina cement was 20%,the 28 d flexural strength and compressive strength increased up to 6.03 MPa and 11.05 MPa, higher than the pure FGD gypsum respectively by 99.67% and 80.56%,softening coefficient reached 0,70, improved by 59.09% when compared with the pure FGD gypsum. The surface of the gypsum crystals formed C-S-H gel anti ettringite after doping with high alumina cement by naicrostructural characterization,which is the main reason to improve the mechanical properties and water resistance of FDG building gypsum.