Roles of recycled concrete powder on the properties of alkali-activated slag: Reaction products and microstructure development

IF 12.7 1区材料科学 Q1 ENGINEERING, MULTIDISCIPLINARY

Composites Part B: Engineering Pub Date : 2025-04-10 DOI:10.1016/j.compositesb.2025.112493

Yuwei Ma , Jihao Gong , Xiaowei Ouyang , Zongjin Li , Hao Wang , Jiyang Fu

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引用次数: 0

Abstract

This study investigated the potential utilization of recycled concrete powders (RCP), obtained from demolished old buildings as precursors to produce alkali-activated slag (AAS). These RCPs contained significantly higher amounts of SiO₂ and CaCO₃ while low level of hydration products, thus limiting their potential application for high substitution in Portland cement-based materials. The present study examined the influence of RCP on the heat evolution, reaction product, pore structure, and mechanical strength of the AAS-RCP system. The results revealed that the incorporation of RCP delayed the alkali-activated reaction at the early age. At later ages (28 days), however, the reactive silica and calcium components in RCP gradually dissolved, facilitating the formation of gel phases with high silicate polymerization and contributing to a higher gel pore volume. Additionally, a zeolite-like product, i.e., gismondine, was identified in AAS-RCP. As a result, AAS-RCP exhibited satisfactory mechanical properties at 28 days even with a high RCP addition. The present study demonstrated the promising potential of large-scale incorporation of RCP with alkali-activation technology in producing low-carbon concrete.

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再生混凝土粉对碱活性渣性能的影响：反应产物及微观结构发展

本研究探讨了从废弃旧建筑中获得的再生混凝土粉（RCP）作为生产碱活性渣（AAS）的前驱体的潜在利用潜力。这些rcp含有大量的SiO2和CaCO3，而水化产物含量较低，因此限制了它们在硅酸盐水泥基材料中的高替代应用潜力。研究了RCP对AAS-RCP体系的热演化、反应产物、孔隙结构和机械强度的影响。结果表明，RCP的掺入延缓了早期碱活化反应的发生。然而，在后期（28天），RCP中的活性二氧化硅和钙组分逐渐溶解，促进了高硅酸盐聚合的凝胶相的形成，并有助于更高的凝胶孔体积。此外，在AAS-RCP中鉴定了一种类似沸石的产物，即吉斯蒙丁。结果表明，AAS-RCP在高RCP添加量的情况下，28天的力学性能也令人满意。本研究表明，将RCP与碱活化技术大规模结合生产低碳混凝土具有广阔的潜力。

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来源期刊

Composites Part B: Engineering 工程技术-材料科学：复合

CiteScore

24.40

自引率

11.50%

发文量

784

审稿时长

21 days

期刊介绍： Composites Part B: Engineering is a journal that publishes impactful research of high quality on composite materials. This research is supported by fundamental mechanics and materials science and engineering approaches. The targeted research can cover a wide range of length scales, ranging from nano to micro and meso, and even to the full product and structure level. The journal specifically focuses on engineering applications that involve high performance composites. These applications can range from low volume and high cost to high volume and low cost composite development. The main goal of the journal is to provide a platform for the prompt publication of original and high quality research. The emphasis is on design, development, modeling, validation, and manufacturing of engineering details and concepts. The journal welcomes both basic research papers and proposals for review articles. Authors are encouraged to address challenges across various application areas. These areas include, but are not limited to, aerospace, automotive, and other surface transportation. The journal also covers energy-related applications, with a focus on renewable energy. Other application areas include infrastructure, off-shore and maritime projects, health care technology, and recreational products.