复合促凝剂对CFBFA基泡沫混凝土性能的影响  

Effect of hybrid accelerator on the property of CFBFA-based foamed concrete

作　　者：董必钦[1] 张枭 刘源涛 王琰帅 DONG Biqin;ZHANG Xiao;LIU Yuantao;WANG Yanshuai(College of Civil and Transportation Engineering,Guangdong Province Key Laboratory of Durability for Marine Civil Engineering,Shenzhen Key Laboratory for Low-carbon Construction Material and Technology,Shenzhen University,Shenzhen 518060,Guangdong Province,P.R.China)

机构地区：[1]深圳大学土木与交通工程学院,广东省滨海土木工程耐久性重点实验室,深圳市低碳建筑材料与技术重点实验室,广东深圳518060

出　　处：《深圳大学学报(理工版)》2025年第1期1-9,共9页Journal of Shenzhen University(Science and Engineering)

基　　金：十四五国家科技部重点研发计划资助项目(2022YFB2602600);国家自然科学基金-铁路基础研究联合基金资助项目(U2368209);广东省科技厅粤港科技合作资助项目(2023A0505010020)。

摘　　要：循环流化床固硫灰(circulating fluidized bed fly ash,CFBFA)是现代新型燃煤发电工艺的主要副产品之一,利用CFBFA制备泡沫混凝土可以满足建筑隔墙保温的要求,但大掺量CFBFA会引起泡沫混凝土凝结速度减缓,导致工业化生产周转效率低,生产成本高.采用硫酸铝与氢氧化钙混合制备复合促凝剂,当硫酸铝质量分数为3%时,研究不同氢氧化钙含量(其与硫酸铝的质量比分别为0、0.25、0.50、0.75和1.00)对CFBFA基泡沫混凝土的凝结时间、抗压强度和导热系数的影响.利用X射线衍射、热重分析、扫描电子显微镜以及等温电导率量热法,研究了复合促凝剂对CFBFA基泡沫混凝土早期水化的促进作用机理,通过3D轮廓仪并结合Image-pro软件,分析了泡沫混凝土的孔隙结构.结果表明,当复合促凝剂中氢氧化钙与硫酸铝的质量比为0.25时,与对照组(氢氧化钙质量为0)相比,CFBFA泡沫混凝土的初凝时间缩短了220 min;当复合促凝剂中氢氧化钙与硫酸铝的质量比为0.75时,CFBFA泡沫混凝土3 d的强度可达到10.39 MPa,导热系数为0.30 W·m^(-1)·K^(-1).复合促凝剂促进混凝土在水化早期生成针状的钙矾石,使CFBFA基泡沫混凝土基体更加致密、孔径分布更均匀.复合促凝剂的掺入使CFBFA基泡沫混凝土具有高效批量化生产的潜力以及良好的工程应用前景.Circulating fluidized bed fly ash(CFBFA)is a major by-product of modern coal combustion technologies.Foamed concrete with a high CFBFA content can meet insulation requirements for building partition walls.However,a high CFBFA content slows the setting process of foamed concrete,reducing turnover efficiency in industrial production.A hybrid accelerator was developed using a mixture of aluminum sulfate and calcium hydroxide.With the mass fraction of aluminum sulfate fixed at 3%,the effects of varying mass ratio of calcium hydroxide to aluminum sulfate 0,0.25,0.50,0.75 and 1.00,respectively,on the setting time,compressive strength,and thermal conductivity of CFBFA-based foamed concrete were investigated.The effects of hybrid accelerator on the early hydration of CFBFA-based foamed concrete were studied by X-ray diffraction,thermogravimetric analysis,scanning electron microscopy and isothermal conductivity calorimetry.The pore structure was analyzed using a 3D profiler combined with Image-Pro.The results showed that when the mass ratio of calcium hydroxide to aluminum sulfate in the hybrid accelerator was 0.25,the initial setting time of CFBFA-based foamed concrete was reduced by 220 min compared to the control group without calcium hydroxide.When the mass ratio of calcium hydroxide to aluminum sulfate in the hybrid accelerator was 0.75,the 3 d strength of CFBFA-based foamed concrete reached 10.39 MPa,with a thermal conductivity of 0.30 W·m^(-1)·K^(-1).The hybrid accelerator promoted the generation of needle-like ettringite(AFt)during early hydration,making the CFBFA-based foamed concrete more compact and the pore size distribution more uniform.The hybrid accelerator enables efficient mass production of CFBFA-based foamed concrete and shows promising prospects for engineering applications.

关 键 词：泡沫混凝土 复合促凝剂 循环流化床固硫灰 隔热 孔隙结构 早期强度 钙矾石 

分 类 号：TU528[建筑科学—建筑技术科学]