Shrinkage characteristics of alkali-activated fly ash/slag paste and mortar at early ages
Shrinkage characteristics of alkali-activated fly ash/slag paste and mortar at early ages
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DOI：
10.1016/j.cemconcomp.2014.07.007
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发表时间：
2014-10-01
影响因子：
10.5
通讯作者：
Lee, H. K.
中科院分区：
文献类型：
--
作者：
Lee, N. K.;Jang, J. G.;Lee, H. K.
本研究的目的是研究碱活化粉煤灰/矿渣（以下简称AFS）的收缩特性及其影响因素。进行了化学收缩率、自收缩率和干燥收缩率的测定。通过XRD和SEM/EDS分析表征了反应产物的微观结构。当渣量从10%增加到30%时，基体密度增大，显微组织中Ca/Si比值C-N-A-S-H增大。较高的水玻璃和矿渣含量会引起更多的化学收缩、自收缩和干燥收缩，但会导致更高的抗压强度。从试验结果可以看出，AFS砂浆的自收缩主要是由于硬化状态下的自干燥，而不是由于新鲜状态下的化学收缩引起的体积收缩。AFS膏体比普通硅酸盐水泥（OPC）表现出更高的干收缩率，这可能是由于AFS膏体的介孔体积比OPC膏体大。(C) 2014 Elsevier Ltd.版权所有。
The purpose of this study is to investigate the shrinkage characteristics of alkali-activated fly ash/slag (henceforth simply AFS) and the factors affecting it. A series of tests were conducted to determine the chemical shrinkage, autogenous shrinkage and drying shrinkage. The microstructures and reaction products were also characterized through XRD and SEM/EDS analyses. An increase in the slag content from 10% to 30% resulted in a denser matrix and showed a higher Ca/Si ratio of C-N-A-S-H in the microstructure. Higher sodium silicate and slag contents in a mixture caused more chemical, autogenous, and drying shrinkage, but led to a higher compressive strength. From the test results, it can be concluded that the autogenous shrinkage of AFS mortar occurs mainly due to self-desiccation in hardened state rather than volume contraction by chemical shrinkage in fresh state. The AFS paste showed higher drying shrinkage than ordinary Portland cement (OPC), which may be caused by the higher mesopore volume of the AFS paste compared to that of OPC paste. (C) 2014 Elsevier Ltd. All rights reserved.