Interface structure between coal gangue ceramsite and cement matrix

Due to the shortage of sand and gravel in the construction industry and the growing accumulation of coal gangue in the coal industry, using coal gangue ceramsite (CGC) as the coarse aggregate for concrete presents a new approach for resource utilization. This study aims to investigate the interface...

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Main Authors: Tianyu Han, Renliang Shan, Guoye Jing, Weiping Zhao, Zhenyu Xu, Dongjie Qiao, Haotian Wu
Format: Article
Language:English
Published: Elsevier 2025-07-01
Series:Case Studies in Construction Materials
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Online Access:http://www.sciencedirect.com/science/article/pii/S2214509525004899
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author Tianyu Han
Renliang Shan
Guoye Jing
Weiping Zhao
Zhenyu Xu
Dongjie Qiao
Haotian Wu
author_facet Tianyu Han
Renliang Shan
Guoye Jing
Weiping Zhao
Zhenyu Xu
Dongjie Qiao
Haotian Wu
author_sort Tianyu Han
collection DOAJ
description Due to the shortage of sand and gravel in the construction industry and the growing accumulation of coal gangue in the coal industry, using coal gangue ceramsite (CGC) as the coarse aggregate for concrete presents a new approach for resource utilization. This study aims to investigate the interface between CGC and cement matrix. First, the reactivity of raw coal gangue aggregate (CGAraw) and CGC was analyzed, revealing that the pozzolanic activity of the Al and Si elements in CGC was higher than that of CGAraw. CGC exhibited relatively high cylinder compressive strength compared to other lightweight aggregates. The impact of varying CGC contents on the physical, mechanical, and microstructural properties of concrete was characterized by various methods. Additionally, a modification mechanism of CGC on interface structure was determined. The result indicated that as the CGC content ranged from 0 % to 100 %, the cube compressive strength decreased by 15.04 %, the oven-dry density decreased by 18.07 %, the microhardness of the ITZ increased from 52.12 HV to 106.76 HV, and the thickness of the ITZ decreased from 47.23 μm to 17.21 μm. The activated SiO2 and Al2O3 on the surface layer of CGC reacted with calcium hydroxide during secondary hydration, producing needle-like ettringite (Aft) crystals and flocculent C-S-H gel, which enhanced the bond between the cement matrix and CGC. Considering the secondary hydration of CGC, the oven-dry density formula was modified by genetic algorithm. Additionally, coal gangue ceramsite lightweight high-strength concrete was determined as green concrete by a specific CO2 intensity index. This study could offer technical support for utilizing CGC in the high-strength concrete industry.
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spelling doaj-art-9ecc01a6c87a42b993a8a659a56c1c0c2025-08-20T02:18:34ZengElsevierCase Studies in Construction Materials2214-50952025-07-0122e0469110.1016/j.cscm.2025.e04691Interface structure between coal gangue ceramsite and cement matrixTianyu Han0Renliang Shan1Guoye Jing2Weiping Zhao3Zhenyu Xu4Dongjie Qiao5Haotian Wu6School of Mechanics and Civil Engineering, China University of Mining and Technology-Beijing, Beijing 100083, ChinaSchool of Mechanics and Civil Engineering, China University of Mining and Technology-Beijing, Beijing 100083, China; Corresponding authors.National Key Laboratory of Intelligent Coal Mining and Rock Formation Control, Beijing 100013, China; Corresponding authors.School of Mechanics and Civil Engineering, China University of Mining and Technology-Beijing, Beijing 100083, ChinaSchool of Mechanics and Civil Engineering, China University of Mining and Technology-Beijing, Beijing 100083, ChinaSchool of Mechanics and Civil Engineering, China University of Mining and Technology-Beijing, Beijing 100083, ChinaSchool of Mechanics and Civil Engineering, China University of Mining and Technology-Beijing, Beijing 100083, ChinaDue to the shortage of sand and gravel in the construction industry and the growing accumulation of coal gangue in the coal industry, using coal gangue ceramsite (CGC) as the coarse aggregate for concrete presents a new approach for resource utilization. This study aims to investigate the interface between CGC and cement matrix. First, the reactivity of raw coal gangue aggregate (CGAraw) and CGC was analyzed, revealing that the pozzolanic activity of the Al and Si elements in CGC was higher than that of CGAraw. CGC exhibited relatively high cylinder compressive strength compared to other lightweight aggregates. The impact of varying CGC contents on the physical, mechanical, and microstructural properties of concrete was characterized by various methods. Additionally, a modification mechanism of CGC on interface structure was determined. The result indicated that as the CGC content ranged from 0 % to 100 %, the cube compressive strength decreased by 15.04 %, the oven-dry density decreased by 18.07 %, the microhardness of the ITZ increased from 52.12 HV to 106.76 HV, and the thickness of the ITZ decreased from 47.23 μm to 17.21 μm. The activated SiO2 and Al2O3 on the surface layer of CGC reacted with calcium hydroxide during secondary hydration, producing needle-like ettringite (Aft) crystals and flocculent C-S-H gel, which enhanced the bond between the cement matrix and CGC. Considering the secondary hydration of CGC, the oven-dry density formula was modified by genetic algorithm. Additionally, coal gangue ceramsite lightweight high-strength concrete was determined as green concrete by a specific CO2 intensity index. This study could offer technical support for utilizing CGC in the high-strength concrete industry.http://www.sciencedirect.com/science/article/pii/S2214509525004899Coal gangue ceramsite (CGC)Interface structureMicrohardnessOven-dry densityLightweight high-strength concrete
spellingShingle Tianyu Han
Renliang Shan
Guoye Jing
Weiping Zhao
Zhenyu Xu
Dongjie Qiao
Haotian Wu
Interface structure between coal gangue ceramsite and cement matrix
Case Studies in Construction Materials
Coal gangue ceramsite (CGC)
Interface structure
Microhardness
Oven-dry density
Lightweight high-strength concrete
title Interface structure between coal gangue ceramsite and cement matrix
title_full Interface structure between coal gangue ceramsite and cement matrix
title_fullStr Interface structure between coal gangue ceramsite and cement matrix
title_full_unstemmed Interface structure between coal gangue ceramsite and cement matrix
title_short Interface structure between coal gangue ceramsite and cement matrix
title_sort interface structure between coal gangue ceramsite and cement matrix
topic Coal gangue ceramsite (CGC)
Interface structure
Microhardness
Oven-dry density
Lightweight high-strength concrete
url http://www.sciencedirect.com/science/article/pii/S2214509525004899
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AT weipingzhao interfacestructurebetweencoalgangueceramsiteandcementmatrix
AT zhenyuxu interfacestructurebetweencoalgangueceramsiteandcementmatrix
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