CO_(2)矿化改性高钙粉煤灰对水泥砂浆力学性能和微结构的影响  

Effect of CO_(2)-Mineralized High-Calcium Fly Ash on Mechanical Properties and Micro-Structure of Cement Mortar

作　　者：黄煌煌 陈铁锋 高小建[3,4] HUANG Huanghuang;CHEN Tiefeng;GAO Xiaojian(Hubei Longzhong Laboratory,Xiangyang 441000,China;School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,China;School of Civil Engineering,Harbin Institute of Technology,Harbin 150090,China;Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education,Harbin Institute of Technology,Harbin 150090,China)

机构地区：[1]湖北隆中实验室,襄阳441000 [2]武汉理工大学材料科学与工程学院,武汉430070 [3]哈尔滨工业大学土木工程学院,哈尔滨150090 [4]哈尔滨工业大学结构工程灾变与控制教育部重点实验室,哈尔滨150090

出　　处：《硅酸盐通报》2024年第5期1889-1896,共8页Bulletin of the Chinese Ceramic Society

基　　金：湖北隆中实验室自主创新研究项目(2022ZZ-37);宁波市重点研发计划(2023Z101);黑龙江省自然科学基金(LH2023E120)。

摘　　要：为改善高钙粉煤灰在混凝土中的体积安定性和水化活性,本文对高钙粉煤灰进行了CO_(2)矿化改性,研究了不同CO_(2)矿化反应时长下高钙粉煤灰的固碳量和游离氧化钙含量,及CO_(2)矿化改性高钙粉煤灰对水泥砂浆水化热、力学性能和孔隙结构的影响。结果表明,经12 h CO_(2)矿化改性处理,高钙粉煤灰固碳量可超过10%(质量分数),高钙粉煤灰中的游离氧化钙含量明显降低。随着矿化反应时间的延长,掺高钙粉煤灰的水泥浆体水化诱导期缩短,早期水化放热量明显降低。CO_(2)矿化改性处理还能减轻高钙粉煤灰对水泥砂浆强度的负面影响,改善水泥砂浆孔隙结构,降低孔隙率和大孔含量,促进水泥的早期水化和水化硅酸钙的成核结晶。To improve the volume stability and hydration activity of high-calcium fly ash(HFA),CO_(2)mineralization treatment was applied in this paper.The CO_(2)uptake percentage and free CaO content of HFA undergone different CO_(2)mineralization duration were experimentally determined.The influence of CO_(2)-mineralized HFA on hydration heat,mechanical properties and pore structure of cement mortar was investigated.The results show that after 12 h of CO_(2)mineralization modification treatment,the carbon sequestration of high calcium fly ash exceeds 10%(mass fraction),and the content of free calcium oxide in high calcium fly ash is significantly reduced.As the prolongation of CO_(2)mineralization,the hydration induction period of cement slurry mixed with HFA is shortened,and the early hydration heat release is significantly reduced.CO_(2)mineralization can also mitigate the adverse impacts of HFA on mechanical strength,as well as improving the pore structure of cement mortar by reducing porosity and volume fraction of large capillary pores.Besides,CO_(2)-mineralized HFA provides more nucleation sites for precipitation of C-S-H,accelerating the early hydration reaction of cement paste.

关 键 词：高钙粉煤灰 CO_(2)矿化 力学性能 孔结构 游离氧化钙 水泥砂浆 

分 类 号：TU528[建筑科学—建筑技术科学]