Fresh and hardened properties of one-part fly ash-based geopolymer binders cured at room temperature: Effect of slag and alkali activators
Fresh and hardened properties of one-part fly ash-based geopolymer binders cured at room temperature: Effect of slag and alkali activators
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室温固化单组分粉煤灰基地质聚合物粘合剂的新鲜和硬化性能：矿渣和碱活化剂的影响
DOI：
10.1016/j.jclepro.2019.03.290
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发表时间：
2019-07-10
影响因子：
11.1
通讯作者：
Shah, Syed Farasat Ali
中科院分区：
文献类型：
--
作者：
Oderji, Sajjad Yousefi;Chen, Bing;Shah, Syed Farasat Ali
地质聚合物被认为是普通波特兰水泥的可持续和环境友好的替代品，因为它们可以减少碳足迹。已知前体和碱活化剂的剂量和类型是影响地质聚合物的新鲜和硬化性质的重要参数。研究了矿渣掺量、碱激发剂种类和用量对单组分粉煤灰基地质聚合物室温固化的影响。不同比例的粉煤灰被替换为炉渣作为富含CaO的前体。通过凝固时间和流动性试验评价了土聚物的新鲜性能，通过抗压和抗折强度试验测定了土聚物的力学性能。利用光学显微镜、X射线衍射仪（XRD）和扫描电镜（SEM-EDS）对样品的矿物学和显微结构进行了分析。试验结果表明，随着矿渣掺量的增加，强度提高，工作性降低。此外，当矿渣取代15%以上的粉煤灰时，出现了微裂纹。在激发剂方面，无水偏硅酸钠提供了最佳的强度和更高的流动性相比，其他。显微结构分析结果表明，当碱激发剂Na 2SiO 3含量小于8%，矿渣替代量小于15%时，体系中存在较多未反应颗粒。(C)2019爱思唯尔有限公司版权所有。
Geopolymers are considered to be a sustainable and environmentally friendly replacement for ordinary Portland cement as they lead to a reduction in carbon footprint. The dosage and type of precursors and alkali activators have been known to be important parameters affecting the fresh and hardened properties of geopolymers. This study investigates the effect of slag content as well as type and dosage of alkali activators on one-part fly ash-based geopolymers cured at room temperature. Different ratios of fly ash were replaced with slag as a CaO-rich precursor. Setting time and flowability tests were carried out to evaluate the fresh properties, compressive and flexural strength experiments were conducted to determine the mechanical properties of the geopolymers. The mineralogy and microstructure of the samples were evaluated by Optical microscope, X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM-EDS) analysis. The experimental results revealed that the increase of slag content improved the strength and reduced workability. Moreover, some microcracks were observed when over 15% of fly ash was replaced with slag. In terms of activators, the sodium metasilicate anhydrous provided optimum strength and higher flowability compared to the others. Microstructural analysis results showed the presence of more unreacted particles when less than 8% Na2SiO3 content as alkaline activator and also less than 15% slag as replacement was used in the system. (C) 2019 Elsevier Ltd. All rights reserved.