Reaction, Phases, and Microstructure of Fly Ash-Based Alkali-Activated Materials
Reaction, Phases, and Microstructure of Fly Ash-Based Alkali-Activated Materials
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DOI：
10.3151/jact.17.93
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发表时间：
2019-03-01
影响因子：
2
通讯作者：
Araki, Yoshikazu
中科院分区：
文献类型：
--
作者：
Matsuda, Akira;Maruyama, Ippei;Araki, Yoshikazu
碱性活化剂对粉煤灰基碱活化制品的微观结构和力学性能有显着影响。本文旨在鉴定不同 Na2O 浓度和不同 SiO2/Na2O 比的碱性活化剂活化粉煤灰 (FA) 的反应产物。使用 NaOH 溶液 (NA)、NaOH 和硅酸钠溶液 (MIX) 的混合物以及硅酸钠溶液 (LG) 来活化粉煤灰。使用不同的技术来表征活化粉煤灰的反应产物，包括 Rietveld 精修的 X 射线衍射 (XRD)、衰减全反射傅里叶变换红外 (ATR-FTIR)、Si-29 偶极去耦 (DD) 磁天使旋转/核磁共振 (Si-29) MAS/NMR) 和 Al-27 MAS NMR、场发射扫描电子显微镜 (FE-SEM) 以及能量色散 X 射线 (EDX) 分析仪。并利用维氏压头对粉煤灰基碱活化产品进行了压痕测试。结果表明，当使用硅酸钠作为碱性活化剂时，粉煤灰碱活化的主要反应产物是高硅铝比的钠铝硅酸盐凝胶（地质聚合物），而当用NaOH溶液或NaOH与硅酸钠溶液的混合物活化粉煤灰时，沸石作为少数相出现。此外，活化剂溶液中的Na2O含量和SiO2/Na2O比影响碱活化材料中形成的非晶相和Q(4)(mAl)单元的量，并反映机械性能。
The alkaline activator has a significant effect on the microstructure and mechanical properties of fly ash-based alkali activated products. This paper aims to identify the reaction products of fly ash (FA) activated with alkaline activators of different concentrations of Na2O and different SiO2/Na2O ratios. NaOH solution (NA), a mixture of NaOH and sodium silicate solution (MIX) and sodium silicate solution (LG) were used to activate fly ash.Different techniques were used to characterize the reaction products of activated fly ash including X-ray diffraction (XRD) with Rietveld refinements, attenuated total reflectance Fourier transformer infrared (ATR-FTIR), Si-29 dipolar-decoupling (DD) magnetic angel spinning/nuclear magnetic resonance (Si-29 MAS/NMR) and Al-27 MAS NMR, field emission scanning electron microscopy (FE-SEM) attached with energy-dispersive X-ray (EDX) analyzer. Also, the fly ash-based alkali activated products were indentation tested using a Vickers indenter.The results revealed that the main reaction product of alkali activation of fly ash is a sodium aluminosilicate gel (geopolymer) with high Si/Al ratio when sodium silicate was used as alkaline activator, while zeolite appeared as minority phase when fly ash was activated with NaOH solution or a mixture of NaOH and sodium silicate solution. Moreover, Na2O content and SiO2/Na2O ratio in the activator solution influence on the amount of amorphous phase and Q(4)(mAl) units formed in the alkali activated materials and that reflect on the mechanical properties.