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

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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Bibliographic Details
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
Subjects:
ground-granulated blast furnace slag
coal gangue
geopolymers
mechanical properties
microstructure
Online Access:https://www.mdpi.com/2075-5309/15/15/2695
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Summary: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.
ISSN:2075-5309

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