Integrated Mechanical and Eco-Economical Assessments of Fly Ash-Based Geopolymer Concrete
This research evaluates the mechanical properties, environmental impacts, and cost-effectiveness of Hub Coal fly ash (FA)-based geopolymer concrete (FAGPC) as a sustainable alternative to ordinary Portland cement (OPC) concrete. This local FA has not been investigated previously. A total of 24 FAGPC...
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2025-07-01
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| author | Qasim Shaukat Khan Raja Hilal Ahmad Asad Ullah Qazi Syed Minhaj Saleem Kazmi Muhammad Junaid Munir Muhammad Hassan Javed |
| author_facet | Qasim Shaukat Khan Raja Hilal Ahmad Asad Ullah Qazi Syed Minhaj Saleem Kazmi Muhammad Junaid Munir Muhammad Hassan Javed |
| author_sort | Qasim Shaukat Khan |
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| description | This research evaluates the mechanical properties, environmental impacts, and cost-effectiveness of Hub Coal fly ash (FA)-based geopolymer concrete (FAGPC) as a sustainable alternative to ordinary Portland cement (OPC) concrete. This local FA has not been investigated previously. A total of 24 FAGPC mixes were tested under both ambient and heat curing conditions, varying the molarities of sodium hydroxide (NaOH) solution (10-M, 12-M 14-M and 16-M), sodium silicate to sodium hydroxide (Na<sub>2</sub>SiO<sub>3</sub>/NaOH) ratios (1.5, 2.0, and 2.5), and alkaline activator solution to fly ash (AAS/FA) ratios (0.5 and 0.6). The test results demonstrated that increasing NaOH molarity enhances the compressive strength (CS.) by 145% under ambient curing, with a peak CS. of 32.8 MPa at 16-M NaOH, and similarly, flexural strength (FS.) increases by 90% with a maximum FS. of 6.5 MPa at 14-M NaOH. Conversely, increasing the Na<sub>2</sub>SiO<sub>3</sub>/NaOH ratio to 2.5 reduced the CS. and FS. of ambient-cured specimens by 12.5% and 10.5%, respectively. Microstructural analysis revealed that higher NaOH molarity produced a denser, more homogeneous matrix, supported by increased Si–O–Al bond formation observed through energy-dispersive X-ray spectrometry. Environmentally, FAGPC demonstrated a 35–40% reduction in embodied CO<sub>2</sub> emissions compared to OPC, although the production costs of FAGPC were 30–35% higher, largely due to the expense of alkaline activators. These findings highlight the potential of FAGPC as a low-carbon alternative to OPC concrete, balancing enhanced mechanical performance with sustainability. New, green, and cheap activation solutions are sought for a new generation of more sustainable and affordable FAGPC. |
| format | Article |
| id | doaj-art-e6eb75333e4f4dbeb026cdf88e80ada3 |
| institution | Kabale University |
| issn | 2075-5309 |
| language | English |
| publishDate | 2025-07-01 |
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| spelling | doaj-art-e6eb75333e4f4dbeb026cdf88e80ada32025-08-20T03:58:30ZengMDPI AGBuildings2075-53092025-07-011514255510.3390/buildings15142555Integrated Mechanical and Eco-Economical Assessments of Fly Ash-Based Geopolymer ConcreteQasim Shaukat Khan0Raja Hilal Ahmad1Asad Ullah Qazi2Syed Minhaj Saleem Kazmi3Muhammad Junaid Munir4Muhammad Hassan Javed5Civil Engineering Department, University of Engineering and Technology, Lahore 54890, PakistanCivil Engineering Department, University of Engineering and Technology, Lahore 54890, PakistanCivil Engineering Department, University of Engineering and Technology, Lahore 54890, PakistanSchool of Mechanics and Construction Engineering, Jinan University, Guangzhou 510632, ChinaSchool of Mechanics and Construction Engineering, Jinan University, Guangzhou 510632, ChinaCivil Engineering Department, University of Engineering and Technology, Lahore 54890, PakistanThis research evaluates the mechanical properties, environmental impacts, and cost-effectiveness of Hub Coal fly ash (FA)-based geopolymer concrete (FAGPC) as a sustainable alternative to ordinary Portland cement (OPC) concrete. This local FA has not been investigated previously. A total of 24 FAGPC mixes were tested under both ambient and heat curing conditions, varying the molarities of sodium hydroxide (NaOH) solution (10-M, 12-M 14-M and 16-M), sodium silicate to sodium hydroxide (Na<sub>2</sub>SiO<sub>3</sub>/NaOH) ratios (1.5, 2.0, and 2.5), and alkaline activator solution to fly ash (AAS/FA) ratios (0.5 and 0.6). The test results demonstrated that increasing NaOH molarity enhances the compressive strength (CS.) by 145% under ambient curing, with a peak CS. of 32.8 MPa at 16-M NaOH, and similarly, flexural strength (FS.) increases by 90% with a maximum FS. of 6.5 MPa at 14-M NaOH. Conversely, increasing the Na<sub>2</sub>SiO<sub>3</sub>/NaOH ratio to 2.5 reduced the CS. and FS. of ambient-cured specimens by 12.5% and 10.5%, respectively. Microstructural analysis revealed that higher NaOH molarity produced a denser, more homogeneous matrix, supported by increased Si–O–Al bond formation observed through energy-dispersive X-ray spectrometry. Environmentally, FAGPC demonstrated a 35–40% reduction in embodied CO<sub>2</sub> emissions compared to OPC, although the production costs of FAGPC were 30–35% higher, largely due to the expense of alkaline activators. These findings highlight the potential of FAGPC as a low-carbon alternative to OPC concrete, balancing enhanced mechanical performance with sustainability. New, green, and cheap activation solutions are sought for a new generation of more sustainable and affordable FAGPC.https://www.mdpi.com/2075-5309/15/14/2555geopolymer concreteNH molarityNa<sub>2</sub>SiO<sub>3</sub>/NaOH ratioAAS/FA ratiose-CO<sub>2</sub> emissionscompressive strength |
| spellingShingle | Qasim Shaukat Khan Raja Hilal Ahmad Asad Ullah Qazi Syed Minhaj Saleem Kazmi Muhammad Junaid Munir Muhammad Hassan Javed Integrated Mechanical and Eco-Economical Assessments of Fly Ash-Based Geopolymer Concrete Buildings geopolymer concrete NH molarity Na<sub>2</sub>SiO<sub>3</sub>/NaOH ratio AAS/FA ratios e-CO<sub>2</sub> emissions compressive strength |
| title | Integrated Mechanical and Eco-Economical Assessments of Fly Ash-Based Geopolymer Concrete |
| title_full | Integrated Mechanical and Eco-Economical Assessments of Fly Ash-Based Geopolymer Concrete |
| title_fullStr | Integrated Mechanical and Eco-Economical Assessments of Fly Ash-Based Geopolymer Concrete |
| title_full_unstemmed | Integrated Mechanical and Eco-Economical Assessments of Fly Ash-Based Geopolymer Concrete |
| title_short | Integrated Mechanical and Eco-Economical Assessments of Fly Ash-Based Geopolymer Concrete |
| title_sort | integrated mechanical and eco economical assessments of fly ash based geopolymer concrete |
| topic | geopolymer concrete NH molarity Na<sub>2</sub>SiO<sub>3</sub>/NaOH ratio AAS/FA ratios e-CO<sub>2</sub> emissions compressive strength |
| url | https://www.mdpi.com/2075-5309/15/14/2555 |
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