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Development of high performance and low-carbon red mud based lightweight concrete: A novel strategy for transforming red mud into sustainable concrete.

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Title: Development of high performance and low-carbon red mud based lightweight concrete: A novel strategy for transforming red mud into sustainable concrete.
Authors: Zhang, Chao1,2 (AUTHOR), Zhang, Xiangkun1 (AUTHOR), Wu, Chiqiu3 (AUTHOR), Yang, Shizhao1 (AUTHOR), Yu, Tao1,2 (AUTHOR) tao-cee.yu@polyu.edu.hk, Wang, Wenlong1 (AUTHOR), Hu, Zhijuan1 (AUTHOR) huzhijuan@sdu.edu.cn
Source: Construction & Building Materials. Sep2025, Vol. 491, pN.PAG-N.PAG. 1p.
Subjects: Carbon emissions, Concrete industry, Thermal conductivity, Compressive strength, Economic impact, Lightweight concrete
Abstract: To facilitate large-scale red mud (RM) utilization in sustainable concrete and reduce industry dependence on cement and natural aggregates, this study developed a high-performance and low-carbon RM-based lightweight concrete (RM-LWC) by using RM based sulfur-aluminate cementitious material (RM-SAC) and RM based lightweight aggregates (RM-LWA). The effects of aggregates type (i.e. high-strength, lightweight and core-shell) on engineering properties of RM-LWC were investigated. The microstructure and micromechanical performance of the interfacial regions of RM-SAC paste and RM-LWA were revealed by elemental mapping and nanoindentation. The results demonstrate that substituting OPC with RM-SAC significantly enhanced mechanical properties and penetration resistance, while incorporating RM-LWA substantially reduced density and thermal conductivity of the concrete. Moreover, the internal curing effect provided by pre-wetting RM-LWA was more efficient in enhancing the performance of interface transition zone (ITZ) in concrete, compare to natural aggregates. The core-shell RM-LWA can further reduce the ITZ width and improve the micromechanics of ITZ in concrete. Based on RM-SAC and three types of RM-LWA, various RM-LWC with density of 1890–2100 kg/m3, compressive strength of 45.5–63.5 MPa, thermal conductivity of 0.47–1.13 W/(m·K) were obtained in this study. Furthermore, to evaluate the environmental and economic impact of the RM-LWC, the CO 2 emission and cost of the RM-LWC, during the whole preparation process were calculated based on the actual production line. Compared to that of traditional concrete, the carbon emission and cost of the RM-LWC was reduced by 21.5 % and 20.1 %, respectively. Overall, this research may provide a novel strategy for transforming RM into sustainable concrete. • High-performance RM-LWC was developed by using RM-SAC and RM-LWA as alternatives to OPC and NAs. • The engineering properties and microstructure evolution of the RM-LWC with different RM-LWA was clarified. • RM-LWC with density of 1890–2100 kg/m3 and compressive strength of 45.5–63.5 MPa were obtained. • The carbon emission and cost of the RM-LWC was evaluated 21.5 % and 20.1 % lower than that of traditional concrete. • A critical perspective and further strategy for recycling RM into sustainable concrete was discussed. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
Description
Abstract:To facilitate large-scale red mud (RM) utilization in sustainable concrete and reduce industry dependence on cement and natural aggregates, this study developed a high-performance and low-carbon RM-based lightweight concrete (RM-LWC) by using RM based sulfur-aluminate cementitious material (RM-SAC) and RM based lightweight aggregates (RM-LWA). The effects of aggregates type (i.e. high-strength, lightweight and core-shell) on engineering properties of RM-LWC were investigated. The microstructure and micromechanical performance of the interfacial regions of RM-SAC paste and RM-LWA were revealed by elemental mapping and nanoindentation. The results demonstrate that substituting OPC with RM-SAC significantly enhanced mechanical properties and penetration resistance, while incorporating RM-LWA substantially reduced density and thermal conductivity of the concrete. Moreover, the internal curing effect provided by pre-wetting RM-LWA was more efficient in enhancing the performance of interface transition zone (ITZ) in concrete, compare to natural aggregates. The core-shell RM-LWA can further reduce the ITZ width and improve the micromechanics of ITZ in concrete. Based on RM-SAC and three types of RM-LWA, various RM-LWC with density of 1890–2100 kg/m3, compressive strength of 45.5–63.5 MPa, thermal conductivity of 0.47–1.13 W/(m·K) were obtained in this study. Furthermore, to evaluate the environmental and economic impact of the RM-LWC, the CO 2 emission and cost of the RM-LWC, during the whole preparation process were calculated based on the actual production line. Compared to that of traditional concrete, the carbon emission and cost of the RM-LWC was reduced by 21.5 % and 20.1 %, respectively. Overall, this research may provide a novel strategy for transforming RM into sustainable concrete. • High-performance RM-LWC was developed by using RM-SAC and RM-LWA as alternatives to OPC and NAs. • The engineering properties and microstructure evolution of the RM-LWC with different RM-LWA was clarified. • RM-LWC with density of 1890–2100 kg/m3 and compressive strength of 45.5–63.5 MPa were obtained. • The carbon emission and cost of the RM-LWC was evaluated 21.5 % and 20.1 % lower than that of traditional concrete. • A critical perspective and further strategy for recycling RM into sustainable concrete was discussed. [ABSTRACT FROM AUTHOR]
ISSN:09500618
DOI:10.1016/j.conbuildmat.2025.142714