Thermal behavior of construction and demolition waste-based geopolymer

IF 7.4 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Construction and Building Materials Pub Date : 2024-10-31 DOI:10.1016/j.conbuildmat.2024.138969

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Abstract

Unsorted Construction and Demolition Waste (CDW) from residential building was tested as solid precursor for obtaining eco-sustainable alkali activated materials with potential applications in the building industry. Suitable reactive systems for material consolidation were tested, including alkaline solutions of sodium hydroxides and/or silicates at different concentrations. Metakaolin (MK) was also tested as an additional precursor together with CDW in different ratios to optimize geopolymerization. An MK/CDW weight ratio of 40/60 and sodium silicate as alkaline activator allowed the production of a well-reacted and cohesive material, with a bulk density of 1.35 g/cm³, a monomodal mesoporosity with a modal pore size of 0.0214 µm (open porosity ∼42 vol%), and a compressive strength of 25 MPa, thus showing similar features to those of pure metakaolin based-geopolymers. Thermal characterization was performed up to 1000°C showing that the material can exhibit thermal stability up to 650°C. Above that temperature a shrinkage due to viscous flow occurred, followed by an expansion over 750°C with the formation of macropores and dense struts. Based on these results, the developed CDW-based geopolymer has the potential for use in green building applications, with adequate thermal stability up to medium-high temperatures.

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基于建筑和拆除废物的土工聚合物的热性能

对住宅楼中未分类的建筑和拆卸废物（CDW）进行了测试，以作为获得生态可持续的碱活性材料的固体前体，这些材料在建筑业中具有潜在的应用价值。测试了合适的材料固化反应体系，包括不同浓度的氢氧化钠和/或硅酸盐碱性溶液。此外，还测试了偏高岭土（MK）作为一种额外的前驱体，以不同的比例与 CDW 一起优化土工聚合。MK/CDW 重量比为 40/60，硅酸钠作为碱性活化剂，可生产出反应良好的内聚材料，体积密度为 1.35 g/cm3，单模态中孔率，模态孔径为 0.0214 µm（开孔率 ∼ 42 vol%），抗压强度为 25 MPa，因此显示出与纯偏高岭土基土工聚合物相似的特性。在高达 1000°C 的温度下进行的热特性分析表明，该材料的热稳定性可达 650°C。温度超过 650°C 时，材料会因粘性流动而收缩，超过 750°C 时材料会膨胀，并形成大孔和致密支柱。基于这些结果，所开发的基于 CDW 的土工聚合物具有在中高温下保持足够热稳定性的潜力，可用于绿色建筑应用。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Construction and Building Materials 工程技术-材料科学：综合

CiteScore

13.80

自引率

21.60%

发文量

3632

审稿时长

82 days

期刊介绍： Construction and Building Materials offers an international platform for sharing innovative and original research and development in the realm of construction and building materials, along with their practical applications in new projects and repair practices. The journal publishes a diverse array of pioneering research and application papers, detailing laboratory investigations and, to a limited extent, numerical analyses or reports on full-scale projects. Multi-part papers are discouraged. Additionally, Construction and Building Materials features comprehensive case studies and insightful review articles that contribute to new insights in the field. Our focus is on papers related to construction materials, excluding those on structural engineering, geotechnics, and unbound highway layers. Covered materials and technologies encompass cement, concrete reinforcement, bricks and mortars, additives, corrosion technology, ceramics, timber, steel, polymers, glass fibers, recycled materials, bamboo, rammed earth, non-conventional building materials, bituminous materials, and applications in railway materials.