大掺量磷石膏矿渣水泥的水化历程与长期强度研究  

Hydration Process and Long-Term Strength of Gypsum Slag Cement with High Content of Phosphogypsum

作　　者：廖宜顺[1,2,3] 汪凯 李豪 LIAO Yishun;WANG Kai;LI Hao(School of Urban Construction,Wuhan University of Science and Technology,Wuhan 430065,China;Institute of High-Performance Engineering Structure,Wuhan University of Science and Technology,Wuhan 430065,China;Hubei Provincial Engineering Research Center of Urban Regeneration,Wuhan 430065,China)

机构地区：[1]武汉科技大学城市建设学院,武汉430065 [2]武汉科技大学高性能工程结构研究院,武汉430065 [3]城市更新湖北省工程研究中心,武汉430065

出　　处：《硅酸盐通报》2023年第12期4408-4415,共8页Bulletin of the Chinese Ceramic Society

基　　金：国家自然科学基金(51608402);湖北省建设科技计划项目(厅头〔2021〕2075号-38)。

摘　　要：采用大掺量磷石膏、粒化高炉矿渣和熟石灰制备石膏矿渣水泥,通过水化热、化学收缩、孔溶液pH值和抗压强度试验,并结合XRD和SEM-EDS测试,探究磷石膏掺量对石膏矿渣水泥的水化历程与长期强度的影响规律。结果表明,当磷石膏的掺量从40%增大到70%(质量分数,下同)时,水泥浆体的第三放热峰峰值逐渐减小,14 d化学收缩从0.066 mL·g^(-1)增大到0.193 mL·g^(-1),早期(0~1 d)化学收缩速率明显增大,孔溶液pH值在28 d龄期内趋于稳定,且与28 d龄期相比,90 d龄期试件的抗压强度提高了12.3%~27.8%。XRD和SEM-EDS分析表明,水泥浆体中主要包含二水石膏、石英、钙矾石和C-S-H凝胶等物质。28 d龄期时,随着磷石膏掺量的增大,钙矾石的生成量从7.48%减小到2.84%,C-S-H凝胶的钙硅比(摩尔比)从1.08增大到2.24。A large amount of phosphogypsum,ground granulated blast-furnace slag and slaked lime were employed to prepare the gypsum slag cement.The effect of phosphogypsum content on the hydration process and long-term strength of gypsum slag cement was investigated through hydration heat,chemical shrinkage,pH value of pore solution and compressive strength tests,combined with XRD and SEM-EDS.The results show that the third peak of heat release curves of cement pastes gradually decreases when the phosphogypsum content increases from 40%to 70%(mass fraction,the same below).The chemical shrinkage at 14 d increases from 0.066 mL·g^(-1) to 0.193 mL·g^(-1),and chemical shrinkage rate significantly increases during the early hydration stage(0~1 d).The pH value of pore solution tends to stabilize within 28 d.Compared with 28 d compressive strength,the 90 d compressive strength is enhanced by 12.3%~27.8%.XRD and SEM-EDS reveales that the cement pastes mainly consists of gypsum,quartz,ettringite and C-S-H gel.At the age of 28 d,the ettringite content decreases from 7.48%to 2.84%,and the Ca/Si ratio(molar ratio)of C-S-H gel increases from 1.08 to 2.24 with the increase of phosphogypsum.

关 键 词：磷石膏 石膏矿渣水泥 粒化高炉矿渣 水化热 化学收缩 水化产物 抗压强度 

分 类 号：TQ172[化学工程—水泥工业]