Compressive strength and hydration of high-volume wet-grinded coal fly ash cementitious materials
Compressive strength and hydration of high-volume wet-grinded coal fly ash cementitious materials
复制标题
大掺量湿磨粉煤灰胶凝材料的抗压强度和水化
DOI：
10.1016/j.conbuildmat.2019.02.038
复制
发表时间：
2019-05-10
影响因子：
7.4
通讯作者：
Yang, Jin
中科院分区：
文献类型：
--
作者：
Tan, Hongbo;Nie, Kangjun;Yang, Jin
大掺量粉煤灰（FA）胶凝体系（C-FA）在水泥和混凝土工业中具有巨大的经济效益和环境效益，但其强度发展缓慢限制了其在真实的工程实践中的应用。在这项研究中，FA进行湿磨，以获得超细颗粒。采用D50为19.70 μ m的粗粉煤灰、D50为2.67 μ m的湿磨粉煤灰和7.80 μ m的湿磨粉煤灰三种粉煤灰，设计了C-FA体系中30%、50%和70%的取代率。研究了该体系的抗压强度、水化率和孔结构，并考虑了该体系的成本和CO2排放。结果表明，湿磨2 h可得到D50 = 2.67 μ m的粉煤灰，30%取代率的粉煤灰1d抗压强度比对照提高16%，28 d抗压强度提高22%，50%取代率的粉煤灰28 d抗压强度比对照略有提高;粉煤灰细化了孔隙结构，致密化了硬化体系，促进了火山灰反应，是水泥石强度提高的主要原因。湿磨粉煤灰替代率为30%和50%（D50 = 2.67 μ m）的系统与水泥-生粉煤灰系统相比，具有更大的环境和经济优势。研究结果为粉煤灰的利用和低碳胶凝材料的设计提供了新的思路。(C)2019爱思唯尔有限公司版权所有。
High volume coal fly ash (FA) cementitious system (C-FA) was reported to present great economic and environmental benefits in cement and concrete industry, but the slow strength development limited its use in real engineering practice. In this study, FA was processed by wet-grinding in order to obtain super-fine particles. Three kinds of FA, namely raw FA with D50 (Median particle size) of 19.70 mu m, wet-grinded FA with D50 of 2.67 mu m and 7.80 mu m, were used; 30%, 50%, and 70% replacement ratio in C-FA system were designed. The compressive strength, hydration, and pore structure were investigated, and the cost and CO2 emission of the system were also considered. The results showed that FA with D50 = 2.67 mu m could be obtained by 2 hours' wet-grinding; 30% replacement ratio increased the compressive strength by 16% at 1 d age and 22% at 28 d age in comparison with the reference; surprisingly, 50% replacement ratio even showed slightly higher 28 d strength than that of the reference; the main reason for the increased strength was due to the refined the pore structure, the densified hardened system, and the promoted pozzolanic reaction of FA. The system with 30% and 50% replacement ratio of wetgrinded FA (D50 = 2.67 mu m) showed greater environmental and economic advantages in comparison with cement-raw FA system. Such results would be expected to offer one new way for utilization of FA and the design of low carbon cementitious materials. (C) 2019 Elsevier Ltd. All rights reserved.