大流动性混凝土配合比优化及微结构表征  

MIX PROPORTION OPTIMIZATION OF HIGH FLUIDITY CONCRETE AND ITS MICROSTRUCTURE CHARACTERIZATION

作　　者：黎梦圆 曹丰泽[1] 阎培渝[1] 周予启 张一擎 李洪海 LI Mengyuan;CAO Fengze;YAN Peiyu;ZHOU Yuqi;ZHANG Yiqing;LI Honghai(Department of Civil Engineering,Tsinghua University,Beijing 100084,China;China Construction First Group Construction&Development Co.,Ltd.,Beijing 100013,China)

机构地区：[1]清华大学土木工程系,北京100084 [2]中建一局集团建设发展有限公司,北京100102

出　　处：《工业建筑》2021年第1期135-139,145,共6页Industrial Construction

基　　金：国家重点研发计划项目(2017YFB0310101);中国博士后科学基金(2019TQ0162);国家自然科学基金项目(51878381)。

摘　　要：针对非洲建设工程的实际条件,对比了两种不同配合比的大流动性混凝土的性能和微结构。与现在使用的掺有硅灰的矿渣硅酸盐水泥混凝土相比,优化后的普通硅酸盐水泥混凝土适当降低了水胶比,增加了浆骨比,调整了外加剂的种类和掺量。测定了新拌混凝土的扩展度和硬化混凝土抗压强度,研究了浆体的早期水化放热特性,并通过扫描电镜观察和压汞试验分析了硬化浆体的微观形貌和孔隙特征。结果表明:普通硅酸盐水泥混凝土拌和物的流动性能与保坍性能比掺有硅灰的矿渣硅酸盐水泥混凝土好,各个龄期的抗压强度高。普通硅酸盐水泥浆体早期水化程度比掺有硅灰的矿渣硅酸盐水泥浆体高,浆体结构更为致密。According to the actual conditions of construction projects in Africa,the properties and microstructure of two kinds of high fluidity concrete were compared.Compared with Portland slag cement concrete mixed with silica fumes used now,the optimized ordinary Portland cement concrete had been appropriately reduced the water-binder ratio,increased the paste-aggregate ratio,and adjusted the type and amounts of admixture.Slump flow of fresh concrete and compressive strength of hardened concrete were measured,early hydration exothermic characteristics of paste were studied,and microstructure and pore characteristics of harden paste were analyzed by SEM and MIP.The results showed that the performances of flow,slump retention,and compressive strength at each age of ordinary Portland cement concrete were better than that of slag Portland cement concrete mixed with silica fumes.The early hydration degree of ordinary Portland cement paste was higher than that of slag Portland cement paste mixed with silica fume,and the pore structure of ordinary Portland cement paste was denser.

关 键 词：大流动性混凝土 普通硅酸盐水泥 矿渣硅酸盐水泥 工作性 力学性能 微结构 

分 类 号：TU528[建筑科学—建筑技术科学]