Durability-related properties of alkali-activated recycled aggregate concrete: Effect of alkali equivalent, recycled coarse aggregate replacement rate and slag content

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

Construction and Building Materials Pub Date : 2025-05-30 DOI:10.1016/j.conbuildmat.2025.142018

Guanghui Gao , Hui Xu , Jiuwen Bao , Yanru Wang , Yifei Cui , Qiang Song , Jianwei Sun

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引用次数: 0

Abstract

This study investigated the durability-related properties of alkali-activated recycled aggregate concrete (AA-RAC) incorporating fly ash and slag. The chloride transport, capillary absorption and freeze-thaw cycles tests of AA-RAC with various dosages were further conducted. The compressive strength tests for a series of specimens and their microstructural observations were carried out. The optimizing proportions combination of the alkali equivalent, RCA replacement rate and slag content by comprehensively considering the tested indicators was finally determined. The results indicate that the specimen with 10 % alkali equivalent, no RCA and 40 % slag content (C10-R0) generally exhibited the excellent mechanical and durability properties, and on the contrary, the specimen with 8 % alkali equivalent and 100 % RCAs (A8-R100) showed the poorest performance. The addition of slag significantly promotes the hydration of fly ash, improving the mechanical and durability properties of AA-RAC. Increasing alkali equivalent and slag content effectively decreases the water absorption rate and improves frost resistance of AA-RAC, but chloride diffusion coefficient and its penetration depth increase with an increase of RCA replacement rate. It is preferable to set up compatibility with high slag content, high alkali equivalent, and low RCA replacement rate for achieving the optimized durability-related performance, providing scientific justification for its extensive application in the practical engineering.

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碱活化再生骨料混凝土耐久性相关性能：碱当量、再生粗骨料替代率和矿渣含量的影响

研究了粉煤灰和矿渣掺入碱活化再生骨料混凝土（AA-RAC）的耐久性能。进一步进行了不同剂量AA-RAC的氯离子输运、毛细吸收和冻融循环试验。对一系列试样进行了抗压强度试验和显微组织观察。综合考虑试验指标，最终确定了碱当量、RCA替代率和含渣量的最佳配比组合。结果表明，碱当量为10 %、不含RCA、渣含量为40 % （C10-R0）的试样具有较好的力学性能和耐久性，碱当量为8 %、RCA含量为100 % （A8-R100）的试样力学性能最差。矿渣的加入显著促进了粉煤灰的水化，提高了AA-RAC的力学性能和耐久性。增加碱当量和渣含量可有效降低AA-RAC的吸水率，提高其抗冻性，但氯离子扩散系数和渗透深度随RCA置换率的增加而增大。优选高渣含量、高碱当量、低RCA替代率的相容性，实现最佳的耐久性能，为其在实际工程中的广泛应用提供了科学依据。

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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.