The Influence of Coal Gangue on the Mechanical Properties of Ground-Granulated Blast Furnace Slag-Based Geopolymers

The reuse of coal gangue (CG) and ground-granulated blast furnace slag (GGBFS) to synthesize geopolymers presents a sustainable strategy for industrial waste recycling. This study investigates the influences of various GGBFS/CG mixtures on the mechanical behavior and microstructure of the synthesize...

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Main Authors: Xiaoping Wang, Feng Liu, Weizhi Chen, Kaifeng Xing, Kexian Zhuo, Lijuan Li
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Buildings
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Online Access:https://www.mdpi.com/2075-5309/15/15/2695
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author Xiaoping Wang
Feng Liu
Weizhi Chen
Kaifeng Xing
Kexian Zhuo
Lijuan Li
author_facet Xiaoping Wang
Feng Liu
Weizhi Chen
Kaifeng Xing
Kexian Zhuo
Lijuan Li
author_sort Xiaoping Wang
collection DOAJ
description The reuse of coal gangue (CG) and ground-granulated blast furnace slag (GGBFS) to synthesize geopolymers presents a sustainable strategy for industrial waste recycling. This study investigates the influences of various GGBFS/CG mixtures on the mechanical behavior and microstructure of the synthesized geopolymers. Results show that the geopolymer matrix is composed of calcium aluminosilicate (C-(A)-S-H) and sodium aluminosilicate (N-A-S-H) hydrates, which is essential for enhancing the compressive strength of the specimens. With 100% GGBFS, the geopolymer matrix sets in 17 min, reaching a compressive strength of 107.55 MPa after 28 days. As the CG content increases, both compressive strength and compactness decrease gradually, while the setting time prolongs. When the GGBFS/CG mass ratio is 1:1, the specimens’ setting time increases by 64.7% (from 17 to 28 min). The corresponding compressive strengths at 3 days, 7 days, and 28 days are recorded to be 46.73 MPa, 53.25 MPa, and 54.59 MPa, respectively. Specimens with 100% CG exhibit a prolonged setting time (122 min), but the compressive strength is just 21.80 MPa. Microscopic analysis reveals that specimens with 50% CG have smaller average pore diameters (22.84 nm) and a compact microstructure. These findings indicate that the GGBFS content significantly influences geopolymer performance, highlighting the effective utilization of GGBFS/CG wastes.
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spelling doaj-art-72cd3157ade3414a8c77f3ec524677ea2025-08-20T03:02:58ZengMDPI AGBuildings2075-53092025-07-011515269510.3390/buildings15152695The Influence of Coal Gangue on the Mechanical Properties of Ground-Granulated Blast Furnace Slag-Based GeopolymersXiaoping Wang0Feng Liu1Weizhi Chen2Kaifeng Xing3Kexian Zhuo4Lijuan Li5School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, ChinaSchool of Future Transportation, Guangzhou Maritime University, Guangzhou 510725, ChinaSchool of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, ChinaSchool of Architecture and Engineering, Huangshan University, Huangshan 245041, ChinaBureau of Public Works of Pingshan District, Shenzhen 518118, ChinaSchool of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, ChinaThe reuse of coal gangue (CG) and ground-granulated blast furnace slag (GGBFS) to synthesize geopolymers presents a sustainable strategy for industrial waste recycling. This study investigates the influences of various GGBFS/CG mixtures on the mechanical behavior and microstructure of the synthesized geopolymers. Results show that the geopolymer matrix is composed of calcium aluminosilicate (C-(A)-S-H) and sodium aluminosilicate (N-A-S-H) hydrates, which is essential for enhancing the compressive strength of the specimens. With 100% GGBFS, the geopolymer matrix sets in 17 min, reaching a compressive strength of 107.55 MPa after 28 days. As the CG content increases, both compressive strength and compactness decrease gradually, while the setting time prolongs. When the GGBFS/CG mass ratio is 1:1, the specimens’ setting time increases by 64.7% (from 17 to 28 min). The corresponding compressive strengths at 3 days, 7 days, and 28 days are recorded to be 46.73 MPa, 53.25 MPa, and 54.59 MPa, respectively. Specimens with 100% CG exhibit a prolonged setting time (122 min), but the compressive strength is just 21.80 MPa. Microscopic analysis reveals that specimens with 50% CG have smaller average pore diameters (22.84 nm) and a compact microstructure. These findings indicate that the GGBFS content significantly influences geopolymer performance, highlighting the effective utilization of GGBFS/CG wastes.https://www.mdpi.com/2075-5309/15/15/2695ground-granulated blast furnace slagcoal ganguegeopolymersmechanical propertiesmicrostructure
spellingShingle Xiaoping Wang
Feng Liu
Weizhi Chen
Kaifeng Xing
Kexian Zhuo
Lijuan Li
The Influence of Coal Gangue on the Mechanical Properties of Ground-Granulated Blast Furnace Slag-Based Geopolymers
Buildings
ground-granulated blast furnace slag
coal gangue
geopolymers
mechanical properties
microstructure
title The Influence of Coal Gangue on the Mechanical Properties of Ground-Granulated Blast Furnace Slag-Based Geopolymers
title_full The Influence of Coal Gangue on the Mechanical Properties of Ground-Granulated Blast Furnace Slag-Based Geopolymers
title_fullStr The Influence of Coal Gangue on the Mechanical Properties of Ground-Granulated Blast Furnace Slag-Based Geopolymers
title_full_unstemmed The Influence of Coal Gangue on the Mechanical Properties of Ground-Granulated Blast Furnace Slag-Based Geopolymers
title_short The Influence of Coal Gangue on the Mechanical Properties of Ground-Granulated Blast Furnace Slag-Based Geopolymers
title_sort influence of coal gangue on the mechanical properties of ground granulated blast furnace slag based geopolymers
topic ground-granulated blast furnace slag
coal gangue
geopolymers
mechanical properties
microstructure
url https://www.mdpi.com/2075-5309/15/15/2695
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