Optimizing Mechanical Properties and Environmental Benefits of CFBFA Composite Gravels Through Gypsum, Hydrated Lime Addition, and CO<sub>2</sub> Carbonation Curing

This study explores the potential of utilizing circulating fluidized bed boiler fly ash (CFBFA) in the production of composite gravels, with the aim of achieving performance comparable to natural gravel while promoting sustainability. CFBFA, activated by hydrated lime and gypsum, was investigated fo...

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Main Authors: Nuo Xu, Yuqing He, Rentuoya Sa, Nana Wang, Yuandong Yang, Suxia Ma
Format: Article
Language:English
Published: MDPI AG 2025-02-01
Series:Solids
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Online Access:https://www.mdpi.com/2673-6497/6/1/9
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author Nuo Xu
Yuqing He
Rentuoya Sa
Nana Wang
Yuandong Yang
Suxia Ma
author_facet Nuo Xu
Yuqing He
Rentuoya Sa
Nana Wang
Yuandong Yang
Suxia Ma
author_sort Nuo Xu
collection DOAJ
description This study explores the potential of utilizing circulating fluidized bed boiler fly ash (CFBFA) in the production of composite gravels, with the aim of achieving performance comparable to natural gravel while promoting sustainability. CFBFA, activated by hydrated lime and gypsum, was investigated for its pozzolanic reaction and carbonation curing under simulated coal-fired power plant flue gas conditions (80 °C, 0.4 MPa, 15% CO<sub>2</sub>, 85% N<sub>2</sub>). The study focused on optimizing the ratios of gypsum and hydrated lime in CFBFA-based cementitious materials, with the goal of enhancing their mechanical properties and understanding the underlying hydration and carbonation mechanisms. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to analyze the mineral composition and microstructure of the composite gravels. The results revealed that the optimal gypsum-to-hydrated lime ratio for CFBFA composite gravels is 2:1, achieving a compressive strength of 9.01 MPa after 28 days of carbonation curing. Carbonation curing accelerated hydration, improving the material’s strength, stability, and microstructure. Additionally, the production of CFBFA composite gravels demonstrated significant environmental benefits, reducing Cumulative Energy Demand (CED) by 86.52% and Global Warming Potential (GWP) by 87.81% compared to cement road base materials. This research underscores the potential of CFBFA as a sustainable construction material, with insights into improving its mechanical performance and expanding its large-scale use through carbonation curing with flue gas.
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institution Kabale University
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publishDate 2025-02-01
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spelling doaj-art-e3660a39b1254fd9b9b5fbf88a8e05ca2025-08-20T03:44:05ZengMDPI AGSolids2673-64972025-02-0161910.3390/solids6010009Optimizing Mechanical Properties and Environmental Benefits of CFBFA Composite Gravels Through Gypsum, Hydrated Lime Addition, and CO<sub>2</sub> Carbonation CuringNuo Xu0Yuqing He1Rentuoya Sa2Nana Wang3Yuandong Yang4Suxia Ma5Shanxi Province Key Laboratory of Clean & High Efficient Combustion and Utilization of Circulating Fluidized Bed, Taiyuan University of Technology, 79 Yingze West Street, Taiyuan 030024, ChinaShanxi Province Key Laboratory of Clean & High Efficient Combustion and Utilization of Circulating Fluidized Bed, Taiyuan University of Technology, 79 Yingze West Street, Taiyuan 030024, ChinaShanxi Province Key Laboratory of Clean & High Efficient Combustion and Utilization of Circulating Fluidized Bed, Taiyuan University of Technology, 79 Yingze West Street, Taiyuan 030024, ChinaShanxi Province Key Laboratory of Clean & High Efficient Combustion and Utilization of Circulating Fluidized Bed, Taiyuan University of Technology, 79 Yingze West Street, Taiyuan 030024, ChinaInstitute of Thermal Science and Technology, Shandong University, Jinan 250061, ChinaShanxi Province Key Laboratory of Clean & High Efficient Combustion and Utilization of Circulating Fluidized Bed, Taiyuan University of Technology, 79 Yingze West Street, Taiyuan 030024, ChinaThis study explores the potential of utilizing circulating fluidized bed boiler fly ash (CFBFA) in the production of composite gravels, with the aim of achieving performance comparable to natural gravel while promoting sustainability. CFBFA, activated by hydrated lime and gypsum, was investigated for its pozzolanic reaction and carbonation curing under simulated coal-fired power plant flue gas conditions (80 °C, 0.4 MPa, 15% CO<sub>2</sub>, 85% N<sub>2</sub>). The study focused on optimizing the ratios of gypsum and hydrated lime in CFBFA-based cementitious materials, with the goal of enhancing their mechanical properties and understanding the underlying hydration and carbonation mechanisms. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to analyze the mineral composition and microstructure of the composite gravels. The results revealed that the optimal gypsum-to-hydrated lime ratio for CFBFA composite gravels is 2:1, achieving a compressive strength of 9.01 MPa after 28 days of carbonation curing. Carbonation curing accelerated hydration, improving the material’s strength, stability, and microstructure. Additionally, the production of CFBFA composite gravels demonstrated significant environmental benefits, reducing Cumulative Energy Demand (CED) by 86.52% and Global Warming Potential (GWP) by 87.81% compared to cement road base materials. This research underscores the potential of CFBFA as a sustainable construction material, with insights into improving its mechanical performance and expanding its large-scale use through carbonation curing with flue gas.https://www.mdpi.com/2673-6497/6/1/9circulating fluidized bed boiler fly ashCFBFA composite gravelscarbonation curingmechanical propertiescumulative energy demandglobal warming potential
spellingShingle Nuo Xu
Yuqing He
Rentuoya Sa
Nana Wang
Yuandong Yang
Suxia Ma
Optimizing Mechanical Properties and Environmental Benefits of CFBFA Composite Gravels Through Gypsum, Hydrated Lime Addition, and CO<sub>2</sub> Carbonation Curing
Solids
circulating fluidized bed boiler fly ash
CFBFA composite gravels
carbonation curing
mechanical properties
cumulative energy demand
global warming potential
title Optimizing Mechanical Properties and Environmental Benefits of CFBFA Composite Gravels Through Gypsum, Hydrated Lime Addition, and CO<sub>2</sub> Carbonation Curing
title_full Optimizing Mechanical Properties and Environmental Benefits of CFBFA Composite Gravels Through Gypsum, Hydrated Lime Addition, and CO<sub>2</sub> Carbonation Curing
title_fullStr Optimizing Mechanical Properties and Environmental Benefits of CFBFA Composite Gravels Through Gypsum, Hydrated Lime Addition, and CO<sub>2</sub> Carbonation Curing
title_full_unstemmed Optimizing Mechanical Properties and Environmental Benefits of CFBFA Composite Gravels Through Gypsum, Hydrated Lime Addition, and CO<sub>2</sub> Carbonation Curing
title_short Optimizing Mechanical Properties and Environmental Benefits of CFBFA Composite Gravels Through Gypsum, Hydrated Lime Addition, and CO<sub>2</sub> Carbonation Curing
title_sort optimizing mechanical properties and environmental benefits of cfbfa composite gravels through gypsum hydrated lime addition and co sub 2 sub carbonation curing
topic circulating fluidized bed boiler fly ash
CFBFA composite gravels
carbonation curing
mechanical properties
cumulative energy demand
global warming potential
url https://www.mdpi.com/2673-6497/6/1/9
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