The role of fly ash microsphere in the microstructure and macroscopic properties of high-strength concrete

被引：179

作者：

Wang, Qiang ^{[1
]}

Wang, Dengquan ^{[1
]}

Chen, Honghui ^{[1
]}

机构：

[1] Tsinghua Univ, Dept Civil Engn, Beijing 100084, Peoples R China

来源：

CEMENT & CONCRETE COMPOSITES | 2017年 / 83卷

基金：

中国国家自然科学基金;

关键词：

Fly ash microsphere; Silica fume; Hydration; Pore structure; Macroscopic properties; HIGH-PERFORMANCE CONCRETE; DENSIFIED SILICA FUME; AUTOGENOUS SHRINKAGE; MECHANICAL-PROPERTIES; COMPRESSIVE STRENGTH; CEMENT PASTE; PORTLAND-CEMENT; HYDRATION; SLAG; DURABILITY;

D O I：

10.1016/j.cemconcomp.2017.07.021

中图分类号：

TU [建筑科学];

学科分类号：

0813 ;

摘要：

This study applied a type of fly ash microsphere (FAM) collected directly from a high-temperature furnace using ceramic dust tubes to high-strength concrete, and with silica fume as a control admixture, investigated the effects of FAM on the hydration and hardening processes of the cementitious materials and the macroscopic properties of the high-strength concrete. Two cement replacement levels (8% and 15%) and two water-to-binder (WEB) ratios (035 and 0.25) were utilized. The results show that FAM has a relatively high level of early activity; SEM images indicate that a significant portion of the FAM reacted at early ages in the cement-FAM hardened paste. Though the early activity of FAM is lower than that of silica fume, the cement-FAM complex binder has similar hydration properties with the cement silica fume complex binder. At 90 d, FAM consumed less Ca(OH)(2) than silica fume and a significant amount of unreacted FAM remained in the hardened pastes. The contributions of FAM to the pore structure of the hardened pastes are lower than those of silica fume at early ages; however, FAM can significantly improve pore structure at late ages, similar to silica fume. In addition, FAM can improve the flowability, late-age strength, and permeability to chloride ions of concrete, while decreasing early-age autogenous shrinkage. (C) 2017 Elsevier Ltd. All rights reserved.

引用

页码：125 / 137

页数：13

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