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Abubakar UA, Lemar GS, Bello AAD, Ishaq A, Dandajeh AA, Jagun ZT, Houmsi MR. Evaluation of traditional and machine learning approaches for modeling volatile fatty acid concentrations in anaerobic digestion of sludge: potential and challenges. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024:10.1007/s11356-024-33281-2. [PMID: 38649611 DOI: 10.1007/s11356-024-33281-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 04/07/2024] [Indexed: 04/25/2024]
Abstract
This study evaluates models for predicting volatile fatty acid (VFA) concentrations in sludge processing, ranging from classical statistical methods (Gaussian and Surge) to diverse machine learning algorithms (MLAs) such as Decision Tree, XGBoost, CatBoost, LightGBM, Multiple linear regression (MLR), Support vector regression (SVR), AdaBoost, and GradientBoosting. Anaerobic bio-methane potential tests were carried out using domestic wastewater treatment primary and secondary sludge. The tests were monitored over 40 days for variations in pH and VFA concentrations under different experimental conditions. The data observed was compared to predictions from the Gaussian and Surge models, and the MLAs. Based on correlation analysis using basic statistics and regression, the Gaussian model appears to be a consistent performer, with high R2 values and low RMSE, favoring precision in forecasting VFA concentrations. The Surge model, on the other hand, albeit having a high R2, has high prediction errors, especially in dynamic VFA concentration settings. Among the MLAs, Decision Tree and XGBoost excel at predicting complicated patterns, albeit with overfitting issues. This study provides insights underlining the need for context-specific considerations when selecting models for accurate VFA forecasts. Real-time data monitoring and collaborative data sharing are required to improve the reliability of VFA prediction models in AD processes, opening the way for breakthroughs in environmental sustainability and bioprocessing applications.
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Affiliation(s)
- Umar Alfa Abubakar
- Department of Water Resources and Environmental Engineering, Ahmadu Bello University, Zaria, 1045, Kaduna, Nigeria
| | - Gul Sanga Lemar
- Department of Botany, Faculty of Biology, Kabul University, Kart-E-Char, Kabul, Afghanistan
| | - Al-Amin Danladi Bello
- Department of Water Resources and Environmental Engineering, Ahmadu Bello University, Zaria, 1045, Kaduna, Nigeria
| | - Aliyu Ishaq
- Department of Water Resources and Environmental Engineering, Ahmadu Bello University, Zaria, 1045, Kaduna, Nigeria
| | - Aliyu Adamu Dandajeh
- Department of Water Resources and Environmental Engineering, Ahmadu Bello University, Zaria, 1045, Kaduna, Nigeria
| | - Zainab Toyin Jagun
- School of Built Environment Engineering and Computing, Leeds Beckett University City Campus, Leeds, UK.
| | - Mohamad Rajab Houmsi
- New Era and Development in Civil Engineering Research Group, Scientific Research Center, Al-Ayen University, Thi-Qar, Nasiriyah, 64001, Iraq
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Sai A, Baomin W, Wenxiu C, Ze Y, Chengcheng F. Preparation of geopolymer based on municipal solid waste incineration fly ash-phosphorus slag and its function for solidification of heavy metals. WASTE MANAGEMENT (NEW YORK, N.Y.) 2024; 178:186-198. [PMID: 38401432 DOI: 10.1016/j.wasman.2024.02.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 02/19/2024] [Accepted: 02/21/2024] [Indexed: 02/26/2024]
Abstract
Municipal solid waste incineration fly ash (MSWIFA) contains potential contaminants and needs to be efficiently solidified/stablized and so should be managed properly. To achieve this goal, alkali-activated MSWIFA and phosphorus slag (PS) based geopolymer solidified bodies were investigated. Therefore, the mechanical properties of the solidified body, heavy metal leaching characteristics, heavy metal chemical forms, and heavy metal solidification/stabilization mechanisms were also analyzed. The results show that: The addition of an appropriate amount of PS can promote the strength development of a solidified body. When the mass ratio of MSWIFA to PS is 7:3, the strength of the solidified body reaches 22.8 MPa at 90d curing age, which is 5.3 times higher than that of the unmodified material. The MSWIFA/PS immobilized Zn 99.9 %, Pb 99.4 % and Cd 99.8 % in 60 day leaching tests. Meanwhile, PS can significantly increase the proportion of chemically stabilized forms of heavy metals in the solidified body. PS affects on the hydration process of the solidified body. When the mass fraction of PS doping was 30 %, the main hydration products of the solidified body were calcium silicate hydrate (C-S-H) and calcium alumina (AFt). When the mass fraction of PS is 50 %, the main hydration products are calcium aluminosilicate hydrate (C-A-S-H), sodium aluminosilicate hydrate (N-A-S-H), and AFt. These hydration products have good solidification effects on heavy metals. Therefore, it can be concluded that the MSWIFA/PS solidified body is an environmentally friendly and efficient binder.
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Affiliation(s)
- An Sai
- School of Infrastructure Engineering, Dalian University of Technology, Dalian 116024, Liaoning, China; College of Urban Construction, Hebei Normal University of Science and Technology, Qinhuangdao 066004, China
| | - Wang Baomin
- School of Infrastructure Engineering, Dalian University of Technology, Dalian 116024, Liaoning, China.
| | - Chen Wenxiu
- Qinhuangdao Quality and Technology Supervision and Inspection Institute, Qinhuangdao 066004, China
| | - Yu Ze
- School of Infrastructure Engineering, Dalian University of Technology, Dalian 116024, Liaoning, China
| | - Fan Chengcheng
- School of Infrastructure Engineering, Dalian University of Technology, Dalian 116024, Liaoning, China
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Li Z, Zhang J, Lei Z, Gao M, Sun J, Tong L, Chen S, Wang Y. Designing low-carbon fly ash based geopolymer with red mud and blast furnace slag wastes: Performance, microstructure and mechanism. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 354:120362. [PMID: 38364543 DOI: 10.1016/j.jenvman.2024.120362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 01/07/2024] [Accepted: 02/08/2024] [Indexed: 02/18/2024]
Abstract
In order to tackle the environmental problems induced by Portland cement production and industrial solid wastes landfilling, this study aims to develop novel ternary cementless fly ash-based geopolymer by recycling red mud and blast furnace slag industrial solid wastes. The fresh-state properties, mechanical strength, water permeability, phase assemblage and microstructure were systematically investigated to evaluate the performance variation and reveal the hydration mechanism for geopolymers with different mixing proportions. The results showed that a higher slag content or a lower red mud content could result in the higher fluidity and shorter setting time for fresh mixture. The existence of slag promoted the transformation of N-A-S-H to C-A-S-H gel, which contributed to higher compressive strength and better resistance to water penetration. However, an excessive incorporation of 30% red mud may impede the generation of N-A-S-H gel and form more flocculent-like loose hydrates, thus to mildly degrade the mechanical strength and anti-permeability. The synergetic utilization of red much and blast furnace slag in fly ash-based geopolymer led to much less CO2 emission compared with the condition that red much or slag was singly added, which demonstrated prominent environmental advantages for such kind of ternary cementless geopolymer with equivalent mechanical strength.
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Affiliation(s)
- Zhiping Li
- School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang 330013, China; State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure, East China Jiaotong University, Nanchang 330013, China
| | - Junyi Zhang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
| | - Zuxiang Lei
- School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang 330013, China; State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure, East China Jiaotong University, Nanchang 330013, China.
| | - Mengshi Gao
- School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang 330013, China
| | - Junbo Sun
- Institute for Smart City of Chongqing University in Liyang, Chongqing University, Liyang 213300, China
| | - Lihong Tong
- School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang 330013, China; State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure, East China Jiaotong University, Nanchang 330013, China
| | - Shunman Chen
- School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang 330013, China
| | - Yufei Wang
- School of Design and the Built Environment, Curtin University, Perth, WA 6102, Australia
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Derouiche R, Lemougna PN, Hernandez GM, Gu J, Baklouti S, Rahier H. The Influence of the Thermal Treatment of Copper Slag on the Microstructure and Performance of Phosphate Cements. MATERIALS (BASEL, SWITZERLAND) 2023; 16:6249. [PMID: 37763527 PMCID: PMC10532714 DOI: 10.3390/ma16186249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 09/10/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023]
Abstract
In general, phosphate cements have a very rapid setting reaction at room temperature. The same holds for copper slag-based phosphate cements. This means that using them as a binder, for instance as mortar, is always possible on a small scale, but very difficult on a large scale. In this paper, the heat treatment of the copper slag was shown to be an effective way to increase the setting time and keep the mix workable for an adequate period. The main objective of this research was to examine the changes in the phase composition of quenched copper slag after exposure to 500 °C and to evaluate the impact of these changes on the reactivity of the material in an acidic environment, as well as on the mechanical properties, microstructure, and structure of the produced phosphate cement materials. Various experimental methods were utilized to characterize the raw materials and the obtained phosphate cementitious materials, including isothermal microcalorimetry (TAM Air), thermogravimetric analysis (TGA), infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), as well as the determination of the chemical composition using X-ray fluorescence (XRF) and the particle size distribution. Furthermore, compressive strength tests were conducted to gauge the mechanical resistance of the materials. The main findings of this work revealed that subjecting the copper slag to a thermal treatment of 500 °C induced a partial transformation in its structure. The high temperature caused the oxidation of some of the divalent iron oxide in the slag, leading to the formation of hematite. This treatment increased the setting time and reduced the reactivity of the copper slag with phosphoric acid, ultimately enabling the production of a dense phosphate-based cementitious material with outstanding mechanical properties. The compressive strength of the newly developed cement was recorded to be greater than 78.9 MPa after 7 days, and this strength continued to increase, reaching 82.5 MPa after 28 days.
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Affiliation(s)
- Rania Derouiche
- Department of Materials and Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; (P.N.L.); (G.M.H.); (J.G.); (H.R.)
- Laboratory of Advanced Materials, National School of Engineers of Sfax, University of Sfax, Sfax 3038, Tunisia;
- Strategic Initiative Materials in Flanders (SIM), 9052 Zwijnaarde, Belgium
| | - Patrick Ninla Lemougna
- Department of Materials and Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; (P.N.L.); (G.M.H.); (J.G.); (H.R.)
- Strategic Initiative Materials in Flanders (SIM), 9052 Zwijnaarde, Belgium
- Department of Minerals Engineering, School of Chemical Engineering and Mineral Industries (EGCIM), University of Ngaoundere, Ngaoundere P.O. Box 454, Cameroon
| | - Guillermo Meza Hernandez
- Department of Materials and Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; (P.N.L.); (G.M.H.); (J.G.); (H.R.)
- Strategic Initiative Materials in Flanders (SIM), 9052 Zwijnaarde, Belgium
| | - Jun Gu
- Department of Materials and Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; (P.N.L.); (G.M.H.); (J.G.); (H.R.)
| | - Samir Baklouti
- Laboratory of Advanced Materials, National School of Engineers of Sfax, University of Sfax, Sfax 3038, Tunisia;
| | - Hubert Rahier
- Department of Materials and Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; (P.N.L.); (G.M.H.); (J.G.); (H.R.)
- Strategic Initiative Materials in Flanders (SIM), 9052 Zwijnaarde, Belgium
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5
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Ziejewska C, Bąk A, Hodor K, Hebda M. Eco-Friendly Coal Gangue and/or Metakaolin-Based Lightweight Geopolymer with the Addition of Waste Glass. MATERIALS (BASEL, SWITZERLAND) 2023; 16:6054. [PMID: 37687748 PMCID: PMC10489159 DOI: 10.3390/ma16176054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 08/28/2023] [Accepted: 08/30/2023] [Indexed: 09/10/2023]
Abstract
Massive amounts of deposited coal gangue derived from the mining industry constitute a crucial problem that must be solved. On the other hand, common knowledge about the recycling of glass products and the reuse of waste glass is still insufficient, which in turn causes economic and environmental problems. Therefore, this work investigated lightweight geopolymer foams manufactured based on coal gangue, metakaolin, and a mix of them to evaluate the influence of such waste on the geopolymer matrix. In addition, the effect of 20% (wt.) of waste glass on the foams was determined. Mineralogical and chemical composition, thermal behaviour, thermal conductivity, compressive strength, morphology, and density of foams were investigated. Furthermore, the structure of the geopolymers was examined in detail, including pore and structure thickness, homogeneity, degree of anisotropy, porosity with division for closed and open pores, as well as distribution of additives and pores using micro-computed tomography (microCT). The results show that the incorporation of waste glass increased compressive strength by approximately 54% and 9% in the case of coal-gangue-based and metakaolin-based samples, respectively. The porosity of samples ranged from 67.3% to 58.7%, in which closed pores constituted 0.3-1.8%. Samples had homogeneous distributions of pores and additions. Furthermore, the thermal conductivity ranged from 0.080 W/(m·K) to 0.117 W/(m·K), whereas the degree of anisotropy was 0.126-0.187, indicating that the structure of foams was approximate to isotropic.
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Affiliation(s)
- Celina Ziejewska
- Faculty of Materials Engineering and Physics, Cracow University of Technology, Warszawska 24, 31-155 Cracow, Poland; (C.Z.); (A.B.)
| | - Agnieszka Bąk
- Faculty of Materials Engineering and Physics, Cracow University of Technology, Warszawska 24, 31-155 Cracow, Poland; (C.Z.); (A.B.)
| | - Krzysztof Hodor
- NETZSCH (Netzsch Instrumenty Sp. z o.o.), Halicka 9, 31-036 Cracow, Poland;
| | - Marek Hebda
- Faculty of Materials Engineering and Physics, Cracow University of Technology, Warszawska 24, 31-155 Cracow, Poland; (C.Z.); (A.B.)
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6
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Jaramillo-Fierro X, Gaona S, Ramón J, Valarezo E. Porous Geopolymer/ZnTiO 3/TiO 2 Composite for Adsorption and Photocatalytic Degradation of Methylene Blue Dye. Polymers (Basel) 2023; 15:2697. [PMID: 37376343 DOI: 10.3390/polym15122697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 06/09/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023] Open
Abstract
In this study, GP (geopolymer) and GTA (geopolymer/ZnTiO3/TiO2) geopolymeric materials were prepared from metakaolin (MK) and characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), energy dispersive X-rays (EDX), specific surface area (SSA), and point of zero charge (PZC). The adsorption capacity and photocatalytic activity of the compounds prepared in the form of pellets was determined by degradation of the methylene blue (MB) dye in batch reactors, at pH = 7.0 ± 0.2 and room temperature (20 °C). The results indicate that both compounds are highly efficient at adsorbing MB, with an average efficiency value of 98.5%. The Langmuir isotherm model and the pseudo second order kinetic model provided the best fits to the experimental data for both compounds. In the MB photodegradation experiments under UVB irradiation, GTA reached an efficiency of 93%, being higher than that achieved by GP (4%). Therefore, the incorporation of ZnTiO3/TiO2 in the geopolymeric matrix allowed GTA to achieve higher overall efficiency, by combining adsorption and photocatalysis, compared to the GP compound. The results indicate that the synthesized compounds could be used for up to five consecutive cycles for the removal of MB from wastewater through adsorption and/or photocatalysis processes.
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Affiliation(s)
- Ximena Jaramillo-Fierro
- Departamento de Química, Facultad de Ciencias Exactas y Naturales, Universidad Técnica Particular de Loja, San Cayetano Alto, Loja 1101608, Ecuador
| | - Sneyder Gaona
- Ingeniería Química, Facultad de Ciencias Exactas y Naturales, Universidad Técnica Particular de Loja, San Cayetano Alto, Loja 1101608, Ecuador
| | - John Ramón
- Ingeniería Química, Facultad de Ciencias Exactas y Naturales, Universidad Técnica Particular de Loja, San Cayetano Alto, Loja 1101608, Ecuador
| | - Eduardo Valarezo
- Departamento de Química, Facultad de Ciencias Exactas y Naturales, Universidad Técnica Particular de Loja, San Cayetano Alto, Loja 1101608, Ecuador
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7
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Atienza EM, De Jesus RM, Ongpeng JMC. Development of Foam Fly Ash Geopolymer with Recycled High-Density Polyethylene (HDPE) Plastics. Polymers (Basel) 2023; 15:polym15112413. [PMID: 37299212 DOI: 10.3390/polym15112413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 05/19/2023] [Accepted: 05/19/2023] [Indexed: 06/12/2023] Open
Abstract
Adapting sustainable construction, which involves responsible consumption of natural resources and reducing carbon emissions, could be a unified action to address the intensifying effects of global warming and the increasing rate of waste pollution worldwide. Aiming to lessen the emission from the construction and waste sector and eliminate plastics in the open environment, a foam fly ash geopolymer with recycled High-Density Polyethylene (HDPE) plastics was developed in this study. The effects of the increasing percentages of HDPE on the thermo-physicomechanical properties of foam geopolymer were investigated. The samples' measured density, compressive strength, and thermal conductivity at 0.25% and 0.50% HDPE content was 1593.96 kg/m3 and 1479.06 kg/m3, 12.67 MPa and 7.89 MPa, and 0.352 W/mK and 0.373 W/mK, respectively. Obtained results are comparable to structural and insulating lightweight concretes with a density of less than 1600 kg/m3, compressive strength of greater than 3.5 MPa, and thermal conductivity of less than 0.75 W/mK. Thus, this research concluded that the developed foam geopolymers from recycled HDPE plastics could be a sustainable alternative material and be optimized in the building and construction industry.
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Affiliation(s)
- Emmanuel M Atienza
- Department of Civil Engineering, De La Salle University, Manila 0922, Philippines
| | - Richard M De Jesus
- Department of Civil Engineering, De La Salle University, Manila 0922, Philippines
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Li Q, Cui H, Li Y, Song X, Liu W, Wang Y, Hou H, Zhang H, Li Y, Wang F, Song J, Ye H, Song S, Che T, Shao S, Kong D, Liang B. Challenges and engineering application of landfill leachate concentrate treatment. ENVIRONMENTAL RESEARCH 2023; 231:116028. [PMID: 37150383 DOI: 10.1016/j.envres.2023.116028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 04/27/2023] [Accepted: 04/29/2023] [Indexed: 05/09/2023]
Abstract
Landfill leachate concentrate (LLC) is a concentrated waste stream from landfill leachate treatment systems and has been recognized as a key challenge due to its high concentration of salts, heavy metals, organic matters, etc. Improper management of LLC (e.g. reinjection) would exacerbate the performance of upstream treatment processes and pose risks to the surrounding environments near landfill sites. Addressing the challenge and recovering resources from LLC have thus been attracting considerable attention. Although many LLC treatment technologies have been developed, a comprehensive discussion about the challenges still lacks. This review critically evaluates mainstream LLC treatment technologies, namely incineration, coagulation, advanced oxidation, evaporation and solidification/stabilization. We then introduce a geopolymer-based solidification (GS) process as a promising technology owning to its simple casting process and reusable final product and summarizes engineering applications in China. Finally, we suggest investigating hybrid systems to minimize LLC production and achieve the on-site reuse of LLC. Collectively, this review provides useful information to guide the selection of LLC treatment technologies and suggests a sustainable alternative for large-scale application, while also highlighting the need of joint efforts in the industry to achieve efficient, ecofriendly and economical on-site management of landfill waste streams.
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Affiliation(s)
- Qian Li
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, China
| | - Hanlin Cui
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Yihao Li
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, China
| | - Xin Song
- Solid Waste and Chemicals Management Center, Ministry of Ecology and Environment, Beijing, 100029, China
| | - Wenzong Liu
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, China
| | - Yongxuan Wang
- Shenyang Academy of Environmental Sciences, Shenyang, 110167, China
| | - Haimeng Hou
- Shenyang Academy of Environmental Sciences, Shenyang, 110167, China
| | - Hongbo Zhang
- Everbright Environmental Protection (China) Co. Ltd., Shenzhen, 518000, China
| | - You Li
- Everbright Environmental Protection (China) Co. Ltd., Shenzhen, 518000, China
| | - Fan Wang
- Liaoning HaiTianGe Enviromental Protection Technology Co. Ltd., Fushun, 113122, China
| | - Jun Song
- Liaoning HaiTianGe Enviromental Protection Technology Co. Ltd., Fushun, 113122, China
| | - Hanfeng Ye
- Liaoning HaiTianGe Enviromental Protection Technology Co. Ltd., Fushun, 113122, China
| | - Sirui Song
- Liaoning HaiTianGe Enviromental Protection Technology Co. Ltd., Fushun, 113122, China
| | - Tong Che
- Liaoning HaiTianGe Enviromental Protection Technology Co. Ltd., Fushun, 113122, China
| | - Shuai Shao
- Liaoning HaiTianGe Enviromental Protection Technology Co. Ltd., Fushun, 113122, China
| | - Deyong Kong
- Shenyang Academy of Environmental Sciences, Shenyang, 110167, China; Liaoning HaiTianGe Enviromental Protection Technology Co. Ltd., Fushun, 113122, China.
| | - Bin Liang
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, China.
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9
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Ren C, Li K, Wang Y, Li Y, Tong J, Cai J. Preparation and Hydration Mechanisms of Low Carbon Ferrochrome Slag-Granulated Blast Furnace Slag Composite Cementitious Materials. MATERIALS (BASEL, SWITZERLAND) 2023; 16:2385. [PMID: 36984265 PMCID: PMC10054098 DOI: 10.3390/ma16062385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 03/07/2023] [Accepted: 03/14/2023] [Indexed: 06/18/2023]
Abstract
Low carbon ferrochrome slag (LCFS) is the metallurgical waste slag from the carbon ferrochrome alloy smelting process. Compared with high carbon ferrochrome slag, LCFS has great potential as cementitious material; the chemical compositions of the two types of slag are quite different. In this research, composite cementitious materials are prepared which use low carbon ferrochrome slag and granulated blast furnace slag (GBFS) as the main raw material. Steel slag mud (SSM) and flue gas desulfurization gypsum (FGDG) are used as the activator. In order to find the variety rule of compressive strength on the composite cementitious materials, a three-factor three-level Box-Behnken design is used to discuss the following independent variables: LCFS content, GBFS content, and water-binder ratio. Moreover, the hydration characteristics of the LCFS-GBFS composite cementitious materials is studied in this paper in terms of hydration product, micromorphology, and hydration degree, based on multi-technical microstructural characterizations. The results show that the compressive strength of the LCFS-GBFS composite cementitious materials is significantly affected by single factors and the interaction of two factors. The mechanical property of the mortar samples at 3, 7, and 28 days are 26.6, 35.3, and 42.7 MPa, respectively, when the LCFS-GBFS-SSM-FGDG ratio is 3:5:1:1 and the water-binder ratio is 0.3. The hydration products of LCFS-GBFS composite cementitious materials are mainly amorphous gels (C-S-H gel), ettringite, and Ca(OH)2. With the increase of LCFS content, more hydration products are generated, and the microstructure of the cementitious system becomes more compact, which contributes to the compressive strength. The results of this research can provide a preliminary theoretical foundation for the development of LCFS-GBFS composite cementitious materials and promote the feasibility of its application in the construction industry. Deep hydration mechanism analysis and engineering applications should be studied in the future.
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Affiliation(s)
- Chao Ren
- School of Civil Engineering, Tangshan University, Tangshan 063000, China
- Hebei Key Laboratory of Construction Engineering and Tailings Comprehensive Utilization, Tangshan 063000, China
| | - Keqing Li
- School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yonghua Wang
- School of Civil Engineering, Tangshan University, Tangshan 063000, China
- Hebei Key Laboratory of Construction Engineering and Tailings Comprehensive Utilization, Tangshan 063000, China
| | - Yanfang Li
- School of Civil Engineering, Tangshan University, Tangshan 063000, China
- Hebei Key Laboratory of Construction Engineering and Tailings Comprehensive Utilization, Tangshan 063000, China
| | - Jiannan Tong
- School of Civil Engineering, Tangshan University, Tangshan 063000, China
- Hebei Key Laboratory of Construction Engineering and Tailings Comprehensive Utilization, Tangshan 063000, China
| | - Jingyao Cai
- School of Civil Engineering, Tangshan University, Tangshan 063000, China
- Hebei Key Laboratory of Construction Engineering and Tailings Comprehensive Utilization, Tangshan 063000, China
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Ahmed M, Colajanni P, Pagnotta S. A Review of Current Research on the Use of Geopolymer Recycled Aggregate Concrete for Structural Members. MATERIALS (BASEL, SWITZERLAND) 2022; 15:8911. [PMID: 36556724 PMCID: PMC9782580 DOI: 10.3390/ma15248911] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 12/05/2022] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
Geopolymer cement (GPC) is a sustainable alternative to ordinary Portland cement (OPC) that considerably cuts the emission of carbon dioxide linked to the building of concrete structures. Over the last few decades, while a large number of papers have been written concerning the use of GPC with natural aggregates and OPC with recycled aggregates, few papers have been devoted to investigating the use of Geopolymer Recycled Aggregate Concrete (GRAC) in structural members. Most of them show more interest in the mechanical strength of the material, rather than the structural behavior of RC members. This review critically compiles the present and past research on the behavior of structural members cast with different types and compositions of GRAC. The focus is on the few research studies investigating the structural behavior of GRAC elements, with an analysis of the load-bearing capacity, the load-deflection mechanism, shear behavior, tensile and flexural strength, and ductility of GRAC structural members. This review aims to indicate the research and experimental tests needed in the future for characterizing the behavior of structural members made up of GRAC.
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