Clean and high-value recycling approach for waste concrete powder: Mechano-chemical activation of pozzolanic activity

IF 4.5 2区工程技术 Q2 ENGINEERING, CHEMICAL

Powder Technology Pub Date : 2025-03-28 DOI:10.1016/j.powtec.2025.120988

Qiang Gao , Xi-guang Li , Xiao-dong Shi , Xin-long Li , Xian-jun Lyu , Xiang-nan Zhu , Yang-guang Ren

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引用次数: 0

Abstract

With the precipitous advancement of the construction industry, the resource utilization of construction waste has attracted extensive attention worldwide. In this study, the effect of mechano-chemical coupling activation on the activation of recycled concrete powder (RCP) pozzolanic activity was explored. Firstly, the effect of mechanical activation on the particle size characteristics and specific surface area (SSA) of RCP was analyzed. The D₅₀ of RCP attains 7.03 μm and the SSA reaches 1429.8 m²/kg after 120 min of grinding, indicating that mechanical activation enhanced the reactivity of RCP. Subsequently, the effects of mechanical activation time and alkali activation on the macroscopic properties of recycled concrete powder-based geopolymer (RCBG) were analyzed to indirectly determine the pozzolanic reactivity of RCP. The maximum compressive strength of RCBG can reach 4.475 MPa at 28 d when the RCP is milled for 120 min and the addition amounts of both CaO and CaSO₄ are 5 %. The pozzolanic activity of RCP is positively correlated with the mechanical milling time, and the excessive addition of alkali activators is detrimental to the development of compressive strength. Conclusively, X-ray diffraction (XRD), thermogravimetric-differential thermogravimetric (TG-DTG), and high-resolution scanning electron microscopy-energy spectroscopy (SEM-EDS) were used to analyze the hydration mechanism of RCBG. XRD and TG analyses show that the presence of CaO and CaSO₄ is favorable to increase the generation amount of hydration products (C-(A)-S-H gel and ettringite), and dense microstructures are formed, thus improving the strength of RCBG.

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来源期刊

Powder Technology 工程技术-工程：化工

CiteScore

9.90

自引率

15.40%

发文量

1047

审稿时长

46 days

期刊介绍： Powder Technology is an International Journal on the Science and Technology of Wet and Dry Particulate Systems. Powder Technology publishes papers on all aspects of the formation of particles and their characterisation and on the study of systems containing particulate solids. No limitation is imposed on the size of the particles, which may range from nanometre scale, as in pigments or aerosols, to that of mined or quarried materials. The following list of topics is not intended to be comprehensive, but rather to indicate typical subjects which fall within the scope of the journal's interests: Formation and synthesis of particles by precipitation and other methods. Modification of particles by agglomeration, coating, comminution and attrition. Characterisation of the size, shape, surface area, pore structure and strength of particles and agglomerates (including the origins and effects of inter particle forces). Packing, failure, flow and permeability of assemblies of particles. Particle-particle interactions and suspension rheology. Handling and processing operations such as slurry flow, fluidization, pneumatic conveying. Interactions between particles and their environment, including delivery of particulate products to the body. Applications of particle technology in production of pharmaceuticals, chemicals, foods, pigments, structural, and functional materials and in environmental and energy related matters. For materials-oriented contributions we are looking for articles revealing the effect of particle/powder characteristics (size, morphology and composition, in that order) on material performance or functionality and, ideally, comparison to any industrial standard.