Effects of Na2O/SiO2 molar ratio on properties of aggregate-paste interphase in fly ash-based geopolymer mixtures through multiscale measurements
Effects of Na2O/SiO2 molar ratio on properties of aggregate-paste interphase in fly ash-based geopolymer mixtures through multiscale measurements
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DOI：
10.1016/j.conbuildmat.2018.10.024
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发表时间：
2018-12-10
影响因子：
7.4
通讯作者：
Moussavi, Sussan
中科院分区：
文献类型：
--
作者：
Khedmati, Mandieh;Alanazi, Hani;Moussavi, Sussan
本文提出了一个多尺度实验研究的影响，不同的Na 2 O/SiO2摩尔比的粉煤灰基地质聚合物混合物的骨料-膏体界面的力学和微观结构特性。通过分析扫描电子显微镜图像，识别微观结构中存在的固相，并量化每个相的出现频率。此外，用压汞法测定了地聚合物试样的孔隙率和孔径分布。通过对大量压痕进行纳米压痕测试，并对测试结果进行统计分析，提取了各个相的弹性模量。通过单边切口梁三点弯曲试验，研究了骨料与浆体的粘结性能。不同长度尺度的测试结果的整合表明，界面区域产生更多的铝硅酸钠水合物（即，N-A-S-H）凝胶比相邻的糊剂区域更好，而与本研究中使用的Na 2 O/SiO2比率无关。此外，Na 2 O/SiO2摩尔比越高，混合物中界面区N-A-S-H凝胶越多，骨料与浆体的结合强度越高。(C)2018爱思唯尔有限公司版权所有。
This paper presents a multiscale experimental study on the influence of different Na2O/SiO2 molar ratios on the mechanical and microstructural characteristics of the aggregate-paste interphase in fly ash-based geopolymer mixtures. By analyzing the scanning electron microscope images, the solid phases present in the microstructure were identified, and the frequency of occurrence of each phase was quantified. In addition, the porosity and pore size distribution of geopolymer specimens were measured by mercury intrusion porosimetry. By conducting nanoindentation tests on a large array of indentations and subsequent statistical analysis of the test results, the elastic moduli of individual phases were extracted. The bond behavior between aggregate and paste was also investigated by conducting the three-point bending test of single edge notched beam specimens. Integration of test results in different length scales showed that interphase region generates more sodium aluminosilicate hydrate (i.e., N-A-S-H) gel than the adjacent paste region regardless of the Na2O/SiO2 ratios used in this study. In addition, the mixture prepared with the higher Na2O/SiO2 molar ratio exhibited more N-A-S-H gel in the interphase zone, which led to increased bonding strength between aggregate and paste. (C) 2018 Elsevier Ltd. All rights reserved.