Non-traditional and Natural Pozzolans as Precursors for Sustainable Alkali-Activated Binders: Reactivity, Phase Assemblage, and Composition Analysis

IF 10.1 1区工程技术 Q1 ENGINEERING, MULTIDISCIPLINARY

Engineering Pub Date : 2025-05-14 DOI:10.1016/j.eng.2025.05.003

Roshan Muththa Arachchige, Shubham Mishra, Jan Olek, Farshad Rajabipour, Sulapha Peethamparan

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引用次数: 0

Abstract

This study evaluates four groups of non-traditional aluminosilicate industrial coal byproducts and natural pozzolans—ground bottom ashes (GBAs), low-purity calcined clays (CCs), volcanic ashes (VAs), and fluidized bed combustion ashes (FBCAs)—as potential precursors for alkali-activated binders. Each group was activated using a mixture of sodium silicate and sodium hydroxide solution under optimized solution parameters. Their reaction behavior, pore solution changes, phase assemblage, and composition were analyzed using various material characterization tools. Results indicate that the reaction rate and total heat are similar to those of conventional fly ash precursors, with total heat release 38%–82% lower than that of Portland cement. Pore solution analyses reveal the formation of typical alkali-activated gel phases, and nuclear magnetic resonance (NMR) revealed calcium sodium aluminosilicate hydrates with aluminum/silicon (Al/Si) ranging 0.07–0.36. A novel reactivity index was proposed using Al-NMR. CCs and GBAs exhibited superior performance compared to other two materials used.

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非传统和天然火山灰作为可持续碱活化粘合剂的前体：反应性、相组合和成分分析

本研究评估了四组非传统铝硅酸盐工业煤副产品和天然火山灰——底灰（GBAs）、低纯度煅烧粘土（CCs）、火山灰（VAs）和流化床燃烧灰（FBCAs）——作为碱活化粘合剂的潜在前体。在优化的溶液参数下，采用水玻璃-氢氧化钠混合溶液对各组进行活化。利用各种材料表征工具分析了它们的反应行为、孔隙溶液变化、相组合和组成。结果表明，该材料的反应速率和总放热与常规粉煤灰前驱体相似，总放热比硅酸盐水泥低38% ~ 82%。孔溶液分析显示形成了典型的碱活化凝胶相，核磁共振（NMR）显示铝硅酸钙钠水合物，铝硅比（Al/Si）在0.07-0.36之间。利用Al-NMR提出了一种新的反应性指标。与使用的其他两种材料相比，CCs和gba表现出优越的性能。

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来源期刊

Engineering Environmental Science-Environmental Engineering

自引率

1.60%

发文量

335

审稿时长

35 days

期刊介绍： Engineering, an international open-access journal initiated by the Chinese Academy of Engineering (CAE) in 2015, serves as a distinguished platform for disseminating cutting-edge advancements in engineering R&D, sharing major research outputs, and highlighting key achievements worldwide. The journal's objectives encompass reporting progress in engineering science, fostering discussions on hot topics, addressing areas of interest, challenges, and prospects in engineering development, while considering human and environmental well-being and ethics in engineering. It aims to inspire breakthroughs and innovations with profound economic and social significance, propelling them to advanced international standards and transforming them into a new productive force. Ultimately, this endeavor seeks to bring about positive changes globally, benefit humanity, and shape a new future.