PERTANIKA JOURNAL OF SCIENCE AND TECHNOLOGY

Fly-ash geopolymer composites are an exciting advancement in eco-friendly construction materials. Fly-ash has become a sustainable alternative to regular cement because the approach addresses critical concerns in construction, such as high energy use, excessive carbon emissions and the challenge of managing industrial waste. In this review, a brief discussion on how fly-ash geopolymer composites could transform construction practices and reduce their impact on the environment. The construction industry is a major contributor to climate change, whereas industrial byproducts like fly-ash can also be an environmental challenge. Thus, the fly-ash geopolymer composites offer an innovative solution by reusing this waste to create environmentally friendly binding materials. Fly-ash can effectively replace traditional cement in construction, improving the durability and sustainability of buildings. By reducing our reliance on regular cement, these composites could revolutionise construction practices across various industries. Developing and widely adopting fly-ash geopolymer composites could bring substantial benefits. It could significantly reduce the construction industry''s carbon footprint and contribute to global efforts to combat climate change. Additionally, ongoing research aims to enhance these composites' strength, heat resistance, and chemical durability, further promoting sustainable construction and supporting a circular economy by turning industrial waste into valuable construction materials.

• Adewuyi, Y. G. (2021). Recent advances in Fly-Ash-Based geopolymers: Potential on the utilization for sustainable environmental remediation. ACS Omega, 6(24), 15532-15542. https://doi.org/10.1021/acsomega.1c00662

• Akid, A. S. M., Hossain, S., Munshi, M. I. U., Elahi, M. M. A., Sobuz, M. H. R., Tam, V. W. Y., & Islam, M. S. (2023). Assessing the influence of fly-ash and polypropylene fiber on fresh, mechanical and durability properties of concrete. Journal of King Saud University - Engineering Sciences, 35(7), 474-484). https://doi.org/10.1016/j.jksues.2021.06.005

• Al Bakri Abdullah, M. M., Hussin, K., Bnhussain, M., Ismail, K. N., Yahya, Z., & Razak, R. A. (2012). Fly-ash-based geopolymer lightweight concrete using foaming agent. International Journal of Molecular Sciences, 13(6), 7186-7198. https://doi.org/10.3390/ijms13067186

• Al Bakri Abdullah, M. M., Jamaludin, L., Kamarudin, H., Binhussain, M., Ruzaidi Ghazali, C. M., & Ahmad, M. I. (2013). Study on fly-ash based geopolymer for coating applications. Advanced Materials Research, 686(April), 227-233. https://doi.org/10.4028/www.scientific.net/AMR.686.227

• Albidah, A. S. (2021). Effect of partial replacement of geopolymer binder materials on the fresh and mechanical properties: A review. Ceramics International, 47(11), 14923-14943. https://doi.org/10.1016/j.ceramint.2021.02.127

• Alehyen, S., Zerzouri, M., El Alouani, M., El Achouri, M., & Taibi, M. (2017). Porosity and fire resistance of fly-ash based geopolymer. Journal of Materials and Environmental Science, 8(10), 3676-3689.

• Ali, M. F., & Vijayalakshmi Natrajan, M. M. (2021). A Review of geopolymer composite thermal properties. IOP Conference Series: Earth and Environmental Science, 822(1), 012051. https://doi.org/10.1088/1755-1315/822/1/012051

• Al-Majidi, M. H., Lampropoulos, A., Cundy, A., & Meikle, S. (2016). Development of geopolymer mortar under ambient temperature for in situ applications. Construction and Building Materials, 120, 198-211. https://doi.org/10.1016/j.conbuildmat.2016.05.085

• Al-Nini, A., Nikbakht, E., Syamsir, A., Shafiq, N., Mohammed, B. S., Al-Fakih, A., Al-Nini, W., & Amran, Y. H. M. (2020). Flexural behavior of double-skin steel tube beams filled with fiber-reinforced cementitious composite and strengthened with CFRP sheets. Materials, 13(14), 3064. https://doi.org/10.3390/ma13143064

• Alterary, S. S., & Marei, N. H. (2021). Fly-ash properties, characterization, and applications: A review. Journal of King Saud University - Science, 33(6), 101536. https://doi.org/10.1016/j.jksus.2021.101536

• Amran, M., Debbarma, S., & Ozbakkaloglu, T. (2021). Fly ash-based eco-friendly geopolymer concrete: A critical review of the long-term durability properties. Construction and Building Materials, 270, 121857. https://doi.org/10.1016/j.conbuildmat.2020.121857

• Amran, M., Huang, S. S., Onaizi, A. M., Murali, G., & Abdelgader, H. S. (2022). Fire spalling behavior of high-strength concrete: A critical review. Construction and Building Materials, 341(April), 127902. https://doi.org/10.1016/j.conbuildmat.2022.127902

• Atienza, E. M., De Jesus, R. M., & Ongpeng, J. M. C. (2023). Development of foam fly-ash geopolymer with recycled High-Density Polyethylene (HDPE) plastics. Polymers, 15(11), 2413. https://doi.org/10.3390/polym15112413

• Bajpai, R., Choudhary, K., Srivastava, A., Sangwan, K. S., & Singh, M. (2020). Environmental impact assessment of fly-ash and silica fume based geopolymer concrete. Journal of Cleaner Production, 254, 120147. https://doi.org/10.1016/j.jclepro.2020.120147

• Balakumaran, M., Xavier, C. T., Kumar, P. P., Kumar, P. J., & Kumar, G. M. (2015). Comparative studies on floor tiles using geopolymer concrete and cement concrete. International Journal of Engineering Research & Technology, 3(11), 1-4. https://www.ijert.org/research/comparative-studies-on-floor-tiles-using-geopolymer-concrete-and-cement-concrete-IJERTCONV3IS11009.pdf

• Baranwal, A., Yadav, A., & Gupta, S. (2021). A comparative case study on various admixtures used for soil stabilization. Soil Dynamics, Lecture Notes in Civil Engineering, 119, 147-157. https://doi.org/10.1007/978-981-33-4001-5_14

• Bellum, R. R., Muniraj, K., & Madduru, S. R. C. (2020). Influence of slag on mechanical and durability properties of fly ash-based geopolymer concrete. Journal of the Korean Ceramic Society, 57(5), 530-545. https://doi.org/10.1007/s43207-020-00056-7

• Bijeljić, J., & Ristić, N. (2023). The influence of industrial by products on the properties of fly ash based geopolimer composites. Gradjevinski Kalendar, 55(1), 1-44. https://doi.org/10.5937/GK23055001B

• Biondi, L., Perry, M., Vlachakis, C., Wu, Z., Hamilton, A., & McAlorum, J. (2019). Ambient cured fly-ash geopolymer coatings for concrete. Materials, 12(6), 1-24. https://doi.org/10.3390/ma12060923

• Cong, P., & Cheng, Y. (2021). Advances in geopolymer materials: A comprehensive review. Journal of Traffic and Transportation Engineering (English Edition), 8(3), 283-314. https://doi.org/10.1016/j.jtte.2021.03.004

• Ducman, V., & Korat, L. (2016). Characterization of geopolymer fly-ash based foams obtained with the addition of Al powder or H2O2 as foaming agents. Materials Characterization, 113, 207-213. https://doi.org/10.1016/j.matchar.2016.01.019

• Durak, U. (2022). Effect of short-term elevated temperature curing on strength properties and microstructure of fresh fly-ash geopolymer mortar. Arabian Journal of Geosciences, 15(9), 1-11. https://doi.org/10.1007/s12517-022-10050-4

• Estrada-Arreola, F., Pérez-Bueno, J. J., Flores-Ruiz, F. J., León-Sarabia, E., & Espinoza-Beltrán, F. J. (2014). The effect of temperature on micro-mechanical properties of fly-ash based geopolymers activated with nano-SiO2 solution by sol-gel technique. Microscopy: Advances in Scientific Research and Education, 5, 986-991.

• Fediuk, R. S., & Yushin, A. M. (2015). The use of fly-ash the thermal power plants in the construction. IOP Conference Series: Materials Science and Engineering, 93(1),012070. https://doi.org/10.1088/1757-899X/93/1/012070

• Feng, J., Zhang, R., Gong, L., Li, Y., Cao, W., & Cheng, X. (2015). Development of porous fly-ash-based geopolymer with low thermal conductivity. Materials and Design, 65, 529-533. https://doi.org/10.1016/j.matdes.2014.09.024

• Ferdous, W., Manalo, A., Wong, H. S., Abousnina, R., AlAjarmeh, O. S., Zhuge, Y., & Schubel, P. (2020). Optimal design for epoxy polymer concrete based on mechanical properties and durability aspects. Construction and Building Materials, 232, 117229. https://doi.org/10.1016/j.conbuildmat.2019.117229

• Gohatre, O. K., Biswal, M., Mohanty, S., & Nayak, S. K. (2020). Study on thermal, mechanical and morphological properties of recycled poly(vinyl chloride)/fly-ash composites. Polymer International, 69(6), 552-563. https://doi.org/10.1002/pi.5988

• Gollakota, A. R. K., Volli, V., & Shu, C. M. (2019). Progressive utilisation prospects of coal fly-ash: A review. Science of the Total Environment, 672, 951-989. https://doi.org/10.1016/j.scitotenv.2019.03.337

• Gourley, J. T. (2014). Geopolymers in Australia. Journal of the Australian Ceramic Society, 50(1), 102-110.

• Grabias-Blicharz, E., & Franus, W. (2023). A critical review on mechanochemical processing of fly-ash and fly-ash-derived materials. Science of the Total Environment, 860, 160529. https://doi.org/10.1016/j.scitotenv.2022.160529

• Hager, I., Sitarz, M., & Mróz, K. (2021). Fly-ash based geopolymer mortar for high-temperature application – Effect of slag addition. Journal of Cleaner Production, 316, 128168. https://doi.org/10.1016/j.jclepro.2021.128168

• Hamidi, R. M., Siyal, A. A., Luukkonen, T., Shamsuddin, R. M., & Moniruzzaman, M. (2022). Fly-ash geopolymer as a coating material for controlled-release fertilizer based on granulated urea. RSC Advances, 12(51), 33187-33199. https://doi.org/10.1039/d2ra06056f

• Harihanandh, M., Viswanathan, K. E., & Krishnaraja, A. R. (2021). Comparative study on chemical and morphology properties of nano fly-ash in concrete. Materials Today: Proceedings, 45, 3132-3136. https://doi.org/10.1016/j.matpr.2020.12.217

• He, R., Dai, N., & Wang, Z. (2020). Thermal and mechanical properties of geopolymers exposed to high temperature: A literature review. Advances in Civil Engineering, 2020(1), 7532703. https://doi.org/10.1155/2020/7532703

• Ibrahim, W. M. W., Al Bakri Abdullah, M. M., Sandu, A. V., Hussin, K., Sandu, I. G., Ismail, K. N., Kadir, A. A., & Binhussain, M. (2014). Processing and characterization of fly-ash-based geopolymer bricks. Revista de Chimie, 65(11), 1340-1345.

• Imtiaz, L., Rehman, S. K. U., Ali Memon, S., Khizar Khan, M., & Faisal Javed, M. (2020). A review of recent developments and advances in eco-friendly geopolymer concrete. Applied Sciences, 10(21), 7838. https://doi.org/10.3390/app10217838

• Jokūbaitis, A., Marčiukaitis, G., & Valivonis, J. (2020). Bond of bundled strands under static and cyclic load and freezing-thawing effect. Engineering Structures, 208, 109922. https://doi.org/10.1016/j.engstruct.2019.109922

• Karakaş, H., İlkentapar, S., Durak, U., Örklemez, E., Özuzun, S., Karahan, O., & Atiş, C. D. (2023). Properties of fly-ash-based lightweight-geopolymer mortars containing perlite aggregates: Mechanical, microstructure, and thermal conductivity coefficient. Construction and Building Materials, 362, 27-33. https://doi.org/10.1016/j.conbuildmat.2022.129717

• Kaya, M., & Köksal, F. (2022). Physical and mechanical properties of C class fly-ash based light-weight geopolymer mortar produced with expanded vermiculite aggregate. Revista de La Construccion, 21(1), 21-35. https://doi.org/10.7764/RDLC.21.1.21

• Kerchof, B., & Wu, H. (2012). Causes of rail cant and controlling cant through wheel/rail interface management. Proceedings of the 2012 Annual AREMA Conference, 1-41.

• Khatib, J. M., Kayali, O., & Siddique, R. (2009). Dimensional change and strength of mortars containing fly-ash and metakaolin. Journal of Materials in Civil Engineering, 21(9), 523-528. https://doi.org/10.1061/(asce)0899-1561(2009)21:9(523)

• Klima, K. M., Schollbach, K., Brouwers, H. J. H., & Yu, Q. (2022). Thermal and fire resistance of Class F fly-ash based geopolymers – A review. Construction and Building Materials, 323(January), 126529. https://doi.org/10.1016/j.conbuildmat.2022.126529

• Korniejenko, K., Fr ączek, E., Pytlak, E., & Adamski, M. (2016). Mechanical properties of geopolymer composites reinforced with natural fibers. Procedia Engineering, 151, 388-393. https://doi.org/10.1016/j.proeng.2016.07.395

• Latham, J. P., Munjiza, A., Mindel, J., Xiang, J., Guises, R., Garcia, X., Pain, C., Gorman, G., & Piggott, M. (2008). Modelling of massive particulates for breakwater engineering using coupled FEMDEM and CFD. Particuology, 6(6), 572-583. https://doi.org/10.1016/j.partic.2008.07.010

• Lavanya, B., Kuriya, P. D., Suganesh, S., Indrajith, R., & Chokkalingam, R. B. (2020). Properties of geopolymer bricks made with flyash and GGBS. IOP Conference Series: Materials Science and Engineering, 872(1), 012141. https://doi.org/10.1088/1757-899X/872/1/012141

• Le Ping, K. K., Cheah, C. B., Liew, J. J., Siddique, R., Tangchirapat, W., & Johari, M. A. B. M. (2022). Coal bottom ash as constituent binder and aggregate replacement in cementitious and geopolymer composites: A review. Journal of Building Engineering, 52(January), 104369. https://doi.org/10.1016/j.jobe.2022.104369

• Li, J., Dang, X., Zhang, J., Yi, P., & Li, Y. (2023). Mechanical properties of Fly Ash-Slag based geopolymer for repair of road subgrade diseases. Polymers, 15(2), 309. https://doi.org/10.3390/polym15020309

• Li, X., Bai, C., Qiao, Y., Wang, X., Yang, K., & Colombo, P. (2022). Preparation, properties and applications of fly-ash-based porous geopolymers: A review. Journal of Cleaner Production, 359, 132043. https://doi.org/10.1016/j.jclepro.2022.132043

• Li, Y., Shen, J., Lin, H., & Li, Y. (2023). Optimization design for alkali-activated slag-fly ash geopolymer concrete based on artificial intelligence considering compressive strength, cost, and carbon emission. Journal of Building Engineering, 75, 106929. https://doi.org/10.1016/j.jobe.2023.106929

• Li, Z., Fei, M. E., Huyan, C., & Shi, X. (2021). Nano-engineered, fly-ash-based geopolymer composites: An overview. Resources, Conservation and Recycling, 168, 105334. https://doi.org/10.1016/j.resconrec.2020.105334

• Liu, Y., Mo, Z., Su, Y., & Chen, Y. (2022). State-of-the-art controlled low-strength materials using incineration industrial by-products as cementitious materials. Construction and Building Materials, 345(June), 128391. https://doi.org/10.1016/j.conbuildmat.2022.128391

• Luhar, I., & Luhar, S. (2022). A comprehensive review on fly-ash-based geopolymer. Journal of Composites Science, 6(8), 1-59. https://doi.org/10.3390/jcs6080219

• Luna-Galiano, Y., Fernández-Pereira, C., & Izquierdo, M. (2016). Contributions to the study of porosity in fly-ash-based geopolymers. Relationship between degree of reaction, porosity and compressive strength. Materiales de Construccion, 66(324), e098. https://doi.org/10.3989/mc.2016.10215

• Ma, J., & Dehn, F. (2017). Investigations on the coefficient of thermal expansion of a low-calcium fly-ash-based geopolymer concrete. Structural Concrete, 18(5), 781-791. https://doi.org/10.1002/suco.201600211

• Mahmoodi, O., Siad, H., Lachemi, M., Dadsetan, S., & Sahmaran, M. (2021). Development of optimized binary ceramic tile and concrete wastes geopolymer binders for in-situ applications. Journal of Building Engineering, 43(January), 102906. https://doi.org/10.1016/j.jobe.2021.102906

• Maiti, D., & Prasad, B. (2016). Revegetation of fly-ash ‒ A review with emphasis on grass-legume plantation and bioaccumulation of metals. Applied Ecology and Environmental Research, 14(2), 185-212. https://doi.org/10.15666/aeer/1402_185212

• Makgabutlane, B., Maubane-Nkadimeng, M. S., Coville, N. J., & Mhlanga, S. D. (2022). Plastic-fly-ash waste composites reinforced with carbon nanotubes for sustainable building and construction applications: A review. Results in Chemistry, 4(March), 100405. https://doi.org/10.1016/j.rechem.2022.100405

• Marvila, M. T., Azevedo, A. R. G., Delaqua, G. C. G., Mendes, B. C., Pedroti, L. G., & Vieira, C. M. F. (2021). Performance of geopolymer tiles in high temperature and saturation conditions. Construction and Building Materials, 286, 122994. https://doi.org/10.1016/j.conbuildmat.2021.122994

• Mizerová, C., Kusák, I., Rovnaník, P., & Bayer, P. (2019). Enhanced electrical properties of fly ash geopolymer composites with carbon nanotubes. Solid State Phenomena, 296 SSP, 137-142. https://doi.org/10.4028/www.scientific.net/SSP.296.137

• Moujoud, Z., Sair, S., Ait Ousaleh, H., Ayouch, I., El Bouari, A., & Tanane, O. (2023). Geopolymer composites reinforced with natural Fibers: A review of recent advances in processing and properties. Construction and Building Materials, 388(May), 131666. https://doi.org/10.1016/j.conbuildmat.2023.131666

• Narattha, C., Wattanasiriwech, S., & Wattanasiriwech, D. (2022). Thermal and mechanical characterization of fly-ash geopolymer with aluminium chloride and potassium hydroxide treated hemp shiv lightweight aggregate. Construction and Building Materials, 331(January), 127206. https://doi.org/10.1016/j.conbuildmat.2022.127206

• Nasir, N. H. M., Usman, F., Saggaf, A., & Saloma. (2022). Development of composite material from recycled polyethylene terephthalate and fly-ash: Four decades progress review. Current Research in Green and Sustainable Chemistry, 5(January), 100280. https://doi.org/10.1016/j.crgsc.2022.100280

• Nasir, N. H. M., Usman, F., Woen, E. L., Ansari, M. N. M., Supian, A. B. M., & Saloma. (2023). Microstructural and thermal behaviour of composite material from recycled polyethylene terephthalate and fly-ash. Recycling, 8(1). https://doi.org/10.3390/recycling8010011

• Nasvi, M. C. M., Rathnaweera, T. D., & Padmanabhan, E. (2016). Geopolymer as well cement and its mechanical integrity under deep down-hole stress conditions: Application for carbon capture and storage wells. Geomechanics and Geophysics for Geo-Energy and Geo-Resources, 2(4), 245-256. https://doi.org/10.1007/s40948-016-0034-2

• Nayak, D. K., Abhilash, P. P., Singh, R., Kumar, R., & Kumar, V. (2022). Fly-ash for sustainable construction: A review of fly-ash concrete and its beneficial use case studies. Cleaner Materials, 6(September), 100143. https://doi.org/10.1016/j.clema.2022.100143

• Novais, R. M., Buruberri, L. H., Ascensão, G., Seabra, M. P., & Labrincha, J. A. (2016). Porous biomass fly-ash-based geopolymers with tailored thermal conductivity. Journal of Cleaner Production, 119, 99-107. https://doi.org/10.1016/j.jclepro.2016.01.083

• Novais, R. M., Ascensão, G., Tobaldi, D. M., Seabra, M. P., & Labrincha, J. A. (2018). Biomass fly ash geopolymer monoliths for effective methylene blue removal from wastewaters. Journal of Cleaner Production, 171, 783-794. https://doi.org/10.1016/j.jclepro.2017.10.078

• Onutai, S., Sato, J., & Osugi, T. (2023). Possible pathway of zeolite formation through alkali activation chemistry of metakaolin for geopolymer–zeolite composite materials: ATR-FTIR study. Journal of Solid State Chemistry, 319, 123808. https://doi.org/10.1016/j.jssc.2022.123808

• Parcesepe, E., Lima, C., Maddaloni, G., & Pecce, M. R. (2022). Engineering properties of geopolymer concrete: A review. Acta Polytechnica CTU Proceedings, 33, 444-451. https://doi.org/10.14311/APP.2022.33.0444

• Pasupathy, K., Singh Cheema, D., & Sanjayan, J. (2021). Durability performance of fly ash-based geopolymer concrete buried in saline environment for 10 years. Construction and Building Materials, 281, 122596. https://doi.org/10.1016/j.conbuildmat.2021.122596

• Plastics News. (2017, August 21). Australia recycler on track for big railroad tie contract. Plastics News. https://www.plasticsnews.com/article/20170821/NEWS/170829990/australia-recycler-on-track-for-big-railroad-tie-contract

• Poloju, K. K., Annadurai, S., Manchiryal, R. K., Goriparthi, M. R., Baskar, P., Prabakaran, M., & Kim, J. (2023). Analysis of rheological characteristic studies of fly-ash-based geopolymer concrete. Buildings, 13(3), 811. https://doi.org/10.3390/buildings13030811

• Poyyamozhi, M., Murugesan, B., & Rajamanickam, N. (2023). Integrated solar PV and piezoelectric based torched fly-ash tiles for smart building applications with machine learning forecasting. Solar Energy, 258(April), 404-417. https://doi.org/10.1016/j.solener.2023.04.053

• Prusty, J. K., & Patro, S. K. (2015). Properties of fresh and hardened concrete using agro-waste as partial replacement of coarse aggregate - A review. Construction and Building Materials, 82, 101-113. https://doi.org/10.1016/j.conbuildmat.2015.02.063

• Qaidi, S., Najm, H. M., Abed, S. M., Ahmed, H. U., Al Dughaishi, H., Al Lawati, J., Sabri, M. M., Alkhatib, F., & Milad, A. (2022). Fly-ash-based geopolymer composites: A Review of the compressive strength and microstructure analysis. Materials, 15(20), 7098. https://doi.org/10.3390/ma15207098

• Radina, L., Sprince, A., Pakrastins, L., Gailitis, R., & Sakale, G. (2023). Foamed geopolymers: A review of recent studies. Journal of Physics: Conference Series, 2423(1), 012032. https://doi.org/10.1088/1742-6596/2423/1/012032

• Roviello, G., Ricciotti, L., Tarallo, O., Ferone, C., Colangelo, F., Roviello, V., & Cioffi, R. (2016). Innovative fly-ash geopolymer-epoxy composites: Preparation, microstructure and mechanical properties. Materials, 9(6), 461. https://doi.org/10.3390/ma9060461

• Sabarinath, N., & Vittala, V. C. B. (2015). Experimental investigation on fiber reinforced concrete with fly ash and bottom ash as partial replacement of cement and sand. Engineering, Materials Science, Environmental Science, CorpusID:136481629. https://api.semanticscholar.org/CorpusID:136481629

• Salih, A., Rafiq, S., Mahmood, W., Ghafor, K., & Sarwar, W. (2021). Various simulation techniques to predict the compressive strength of cement-based mortar modified with micro-sand at different water-to-cement ratios and curing ages. Arabian Journal of Geosciences, 14(5), 411. https://doi.org/10.1007/s12517-021-06779-z

• Sarath Chandra, K., & Krishnaiah, S. (2022). Strength and leaching characteristics of red mud (bauxite residue) as a geomaterial in synergy with fly ash and gypsum. Transportation Research Interdisciplinary Perspectives, 13, 100566. https://doi.org/10.1016/j.trip.2022.100566

• Selim, M., Metwaly, M., & Elshamy, E. (2024). Performance of recycling concrete in frames provided with infill walls due to lateral loads. Journal of Building Pathology and Rehabilitation, 9(1), 14. https://doi.org/10.1007/s41024-023-00367-2

• Shao, N.-N., Zhang, Y.-B, Liu, Z., Wang, D.-M., & Zhang, Z.-T. (2018). Fabrication of hollow microspheres filled fly-ash based foam geopolymers with ultra-low thermal conductivity and relative high strength. Construction and Building Materials, 185, 567-573. https://doi.org/10.1016/j.conbuildmat.2018.07.077

• Shehata, N., Mohamed, O. A., Sayed, E. T., Abdelkareem, M. A., & Olabi, A. G. (2022). Geopolymer concrete as green building materials: Recent applications, sustainable development and circular economy potentials. Science of the Total Environment, 836, 155577. https://doi.org/10.1016/j.scitotenv.2022.155577

• Shi, X., Zhang, C., Liang, Y., Luo, J., Wang, X., Feng, Y., Li, Y., Wang, Q., & Abomohra, A. E. F. (2021). Life cycle assessment and impact correlation analysis of fly-ash geopolymer concrete. Materials, 14(23), 1-13. https://doi.org/10.3390/ma14237375

• Siyal, A. A., Shamsuddin, M. R., Khan, M. I., Rabat, N. E., Zulfiqar, M., Man, Z., Siame, J., & Azizli, K. A. (2018). A review on geopolymers as emerging materials for the adsorption of heavy metals and dyes. Journal of Environmental Management, 224, 327-339. https://doi.org/10.1016/j.jenvman.2018.07.046

• Sofri, L. A., Abdullah, M. M. A. B., Sandu, A. V., Imjai, T., Vizureanu, P., Hasan, M. R. M., Almadani, M., Aziz, I. H. A., & Rahman, F. A. (2022). Mechanical performance of fly ash based geopolymer (FAG) as road base stabilizer. Materials, 15(20), 7242. https://doi.org/10.3390/ma15207242

• Sonebi, M., Abdalqader, A., Fayyad, T., Amziane, S., & El-Khatib, J. (2022). Effect of fly-ash and metakaolin on the properties of fiber-reinforced cementitious composites: A factorial design approach. Computers and Concrete, 29(5), 347-360. https://doi.org/10.12989/cac.2022.29.5.347

• Sotelo-Piña, C., Aguilera-González, E. N., & Martínez-Luévanos, A. (2019). Geopolymers: Past, present, and future of low carbon footprint eco-materials. Handbook of Ecomaterials, 4, 2765-2785. https://doi.org/10.1007/978-3-319-68255-6_54

• Tao, J. L., Lin, C., Luo, Q. L., Long, W. J., Zheng, S. Y., & Hong, C. Y. (2022). Leveraging internal curing effect of fly ash cenosphere for alleviating autogenous shrinkage in 3D printing. Construction and Building Materials, 346(July), 128247. https://doi.org/10.1016/j.conbuildmat.2022.128247

• U.S. Energy Information Administration. (2022, May 26). Beneficial use of power sector combustion byproducts exceeded material disposed in 2020. U.S. Energy Information Administration. https://www.eia.gov/todayinenergy/detail.php?id=52518

• U.S. Energy Information Administration. (2011, September 28). Renewable energy shows strongest growth in global electric generating capacity. U.S. Energy Information Administration. https://www.eia.gov/todayinenergy/detail.php?id=3270#

• van Gent, M. R. A. (2021). Influence of oblique wave attack on wave overtopping at caisson breakwaters with sea and swell conditions. Coastal Engineering, 164(April), 103834. https://doi.org/10.1016/j.coastaleng.2020.103834

• Vickers, L., Pan, Z., Tao, Z., & Van Riessen, A. (2016). In situ elevated temperature testing of fly ash based geopolymer composites. Materials, 9(6), 445. https://doi.org/10.3390/ma9060445

• Wan Ibrahim, W. M., Hussin, K., Al Bakri Abdullah, M. M., Abdul Kadir, A., & Binhussain, M. (2015). A review of fly-ash-based geopolymer lightweight bricks. Applied Mechanics and Materials, 754-755(April), 452-456. https://doi.org/10.4028/www.scientific.net/amm.754-755.452

• Wan Mastura, W. I., Kamarudin, H., Nizar, I. K., & Al Bakri, A. M. M. (2013). Mechanical performances of fly-ash geopolymer bricks. Advanced Science Letters, 19(1), 186-189. https://doi.org/10.1166/asl.2013.4679

• Wang, M., Kang, J., Liu, W., Su, J., & Li, M. (2022). Research on prediction of compressive strength of fly-ash and slag mixed concrete based on machine learning. PLoS ONE, 17(12 December), 1-18. https://doi.org/10.1371/journal.pone.0279293

• Wang, J., Che, Z., Zhang, K., Fan, Y., Niu, D., & Guan, X. (2023). Performance of recycled aggregate concrete with supplementary cementitious materials (fly ash, GBFS, silica fume, and metakaolin): Mechanical properties, pore structure, and water absorption. Construction and Building Materials, 368, 130455. https://doi.org/10.1016/j.conbuildmat.2023.130455

• Wazien, A. Z. W., Abdullah, M. M. A. B., Abd Razak, R., Rozainy, M. A. Z. M. R., & Tahir, M. F. M. (2016). Strength and density of geopolymer mortar cured at ambient temperature for use as repair material. IOP Conference Series: Materials Science and Engineering, 133(1), 012042. https://doi.org/10.1088/1757-899X/133/1/012042

• Wu, Y., Lu, B., Bai, T., Wang, H., Du, F., Zhang, Y., Cai, L., Jiang, C., & Wang, W. (2019). Geopolymer, green alkali activated cementitious material: Synthesis, applications and challenges. Construction and Building Materials, 224(206), 930-949. https://doi.org/10.1016/j.conbuildmat.2019.07.112

• Yu, G., & Jia, Y. (2022). Microstructure and mechanical properties of fly-ash-based geopolymer cementitious composites. Minerals, 12(7), 853. https://doi.org/10.3390/min12070853

• Zakeri, J. A., & Sadeghi, J. (2007). Field investigation on load distribution and deflections of railway track sleepers. Journal of Mechanical Science and Technology, 21(12), 1948-1956. https://doi.org/10.1007/BF03177452

• Zhang, P., Gao, Z., Wang, J., Guo, J., Hu, S., & Ling, Y. (2020). Properties of fresh and hardened fly-ash/slag based geopolymer concrete: A review. Journal of Cleaner Production, 270, 122389. https://doi.org/10.1016/j.jclepro.2020.122389

• Zhang, Y., Wang, L., Chen, L., Ma, B., Zhang, Y., Ni, W., & Tsang, D. C. W. (2021). Treatment of municipal solid waste incineration fly-ash: State-of-the-art technologies and future perspectives. Journal of Hazardous Materials, 411, 125132. https://doi.org/10.1016/j.jhazmat.2021.125132

• Zhu, J., Wei, Z., Luo, Z., Yu, L., & Yin, K. (2021). Phase changes during various treatment processes for incineration bottom ash from municipal solid wastes: A review in the application-environment nexus. Environmental Pollution, 287(June), 117618. https://doi.org/10.1016/j.envpol.2021.117618

• Zhuang, X. Y., Chen, L., Komarneni, S., Zhou, C. H., Tong, D. S., Yang, H. M., Yu, W. H., & Wang, H. (2016). Fly-ash-based geopolymer: Clean production, properties and applications. Journal of Cleaner Production, 125, 253-267. https://doi.org/10.1016/j.jclepro.2016.03.019

• Zierold, K. M., & Odoh, C. (2020). A review on fly-ash from coal-fired power plants: Chemical composition, regulations, and health evidence. Reviews on Environmental Health, 35(4), 401-418. https://doi.org/10.1515/reveh-2019-0039