{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,17]],"date-time":"2026-03-17T23:54:48Z","timestamp":1773791688089,"version":"3.50.1"},"reference-count":52,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2022,5,5]],"date-time":"2022-05-05T00:00:00Z","timestamp":1651708800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Polish National Agency for Academic Exchange","award":["PPI\/APM\/2018\/1\/00027"],"award-info":[{"award-number":["PPI\/APM\/2018\/1\/00027"]}]},{"name":"Polish National Agency for Academic Exchange","award":["ERA-MIN2-3\/SMART-G\/1\/2022"],"award-info":[{"award-number":["ERA-MIN2-3\/SMART-G\/1\/2022"]}]},{"name":"NCBR and EU","award":["PPI\/APM\/2018\/1\/00027"],"award-info":[{"award-number":["PPI\/APM\/2018\/1\/00027"]}]},{"name":"NCBR and EU","award":["ERA-MIN2-3\/SMART-G\/1\/2022"],"award-info":[{"award-number":["ERA-MIN2-3\/SMART-G\/1\/2022"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Energies"],"abstract":"<jats:p>Two geopolymer foams were prepared from a thermally activated coal gangue containing kaolinite. As the foaming agent, aluminium powder and 36% hydrogen peroxide were used to obtain two levels of porosity. The materials\u2019 high temperature performances were investigated: tensile and compressive strength evolution with temperature. This study shows that the mechanical performances of developed geopolymer foams are similar to foam concrete of the same apparent density. The geopolymer foams from coal gangue present stable mechanical performances up to 600 \u00b0C. When the glass transition temperature is achieved, sintering occurs and mechanical performance increases. SEM observations confirm the glass transition and densification of the matrix at temperatures above 800 \u00b0C. Moreover, the XRD measurements revealed a high amount of mullite that forms at 1000 \u00b0C that explained the observed strength increase. The synthesis of good-quality geopolymer foams from coal gangue and its application as a thermal barrier is feasible. The constant level of porosity and its stable character in the range of temperatures 20\u20131000 \u00b0C ensures stable thermal insulation parameters with increasing temperature, which is extremely important for fire protection.<\/jats:p>","DOI":"10.3390\/en15093363","type":"journal-article","created":{"date-parts":[[2022,5,5]],"date-time":"2022-05-05T13:10:26Z","timestamp":1651756226000},"page":"3363","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":29,"title":["Mechanical Response of Geopolymer Foams to Heating\u2014Managing Coal Gangue in Fire-Resistant Materials Technology"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6219-3256","authenticated-orcid":false,"given":"Mateusz","family":"Sitarz","sequence":"first","affiliation":[{"name":"Chair of Building Materials Engineering, Faculty of Civil Engineering, Cracow University of Technology, 24 Warszawska Street, 31-155 Cracow, Poland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5493-0914","authenticated-orcid":false,"given":"Beata","family":"Figiela","sequence":"additional","affiliation":[{"name":"Chair of Materials Engineering, Faculty of Material Engineering and Physics, Cracow University of Technology, 37 Jana Paw\u0142a II Street, 31-864 Cracow, Poland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5713-9415","authenticated-orcid":false,"given":"Micha\u0142","family":"\u0141ach","sequence":"additional","affiliation":[{"name":"Chair of Materials Engineering, Faculty of Material Engineering and Physics, Cracow University of Technology, 37 Jana Paw\u0142a II Street, 31-864 Cracow, Poland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8265-3982","authenticated-orcid":false,"given":"Kinga","family":"Korniejenko","sequence":"additional","affiliation":[{"name":"Chair of Materials Engineering, Faculty of Material Engineering and Physics, Cracow University of Technology, 37 Jana Paw\u0142a II Street, 31-864 Cracow, Poland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5306-2035","authenticated-orcid":false,"given":"Katarzyna","family":"Mr\u00f3z","sequence":"additional","affiliation":[{"name":"Chair of Building Materials Engineering, Faculty of Civil Engineering, Cracow University of Technology, 24 Warszawska Street, 31-155 Cracow, Poland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2694-5462","authenticated-orcid":false,"given":"Jo\u00e3o","family":"Castro-Gomes","sequence":"additional","affiliation":[{"name":"Centre of Materials and Building Technologies (C\u2013MADE), Department of Civil Engineering and Architecture, University of Beira Interior (UBI), 6201-001 Covilh\u00e3, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2852-8934","authenticated-orcid":false,"given":"Izabela","family":"Hager","sequence":"additional","affiliation":[{"name":"Chair of Building Materials Engineering, Faculty of Civil Engineering, Cracow University of Technology, 24 Warszawska Street, 31-155 Cracow, Poland"}]}],"member":"1968","published-online":{"date-parts":[[2022,5,5]]},"reference":[{"key":"ref_1","unstructured":"Davidovits, J. (2002, January 28\u201329). 30 Years of Successes and Failures in Geopolymer Applications. Market Trends and Potential Breakthroughs. Proceedings of the Geopolymer 2002 Conference, Melbourne, VIC, Australia. Available online: https:\/\/www.geopolymer.org\/wp-content\/uploads\/30YearsGEOP.pdf."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"\u0141ach, M. (2021). Geopolymer Foams\u2014Will They Ever Become a Viable Alternative to Popular Insulation Materials?\u2014A Critical Opinion. Materials, 14.","DOI":"10.3390\/ma14133568"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"126722","DOI":"10.1016\/j.conbuildmat.2022.126722","article-title":"Fire resistance of geopolymer concrete: A critical review","volume":"324","author":"Amran","year":"2022","journal-title":"Constr. Build. Mater."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"410","DOI":"10.1016\/j.proeng.2016.07.350","article-title":"Thermal Insulation and Thermally Resistant Materials Made of Geopolymer Foams","volume":"151","author":"Korniejenko","year":"2016","journal-title":"Procedia Eng."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Korniejenko, K., Figiela, B., Ziejewska, C., Marczyk, J., Bazan, P., Hebda, M., Choi\u0144ska, M., and Lin, W.-T. (2022). Fracture Behavior of Long Fiber Reinforced Geopolymer Composites at Different Operating Temperatures. Materials, 15.","DOI":"10.3390\/ma15020482"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"514","DOI":"10.1016\/j.conbuildmat.2019.06.076","article-title":"A critical review of geopolymer properties for structural fire-resistance applications","volume":"221","author":"Lahoti","year":"2019","journal-title":"Constr. Build. Mater."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Kozub, B., Bazan, P., Gailitis, R., Korniejenko, K., and Mierzwi\u0144ski, D. (2021). Foamed Geopolymer Composites with the Addition of Glass Wool Waste. Materials, 14.","DOI":"10.3390\/ma14174978"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1583","DOI":"10.1016\/j.cemconres.2007.08.021","article-title":"Comparative performance of geopolymers made with metakaolin and fly ash after exposure to elevated temperatures","volume":"37","author":"Kong","year":"2007","journal-title":"Cem. Concr. Res."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Le, V.S., Louda, P., Tran, H.N., Nguyen, P.D., Bakalova, T., Ewa Buczkowska, K., and Dufkova, I. (2020). Study on Temperature-Dependent Properties and Fire Resistance of Metakaolin-Based Geopolymer Foams. Polymers, 12.","DOI":"10.3390\/polym12122994"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1186\/s40069-018-0267-2","article-title":"Behaviour of Carbon and Basalt Fibres Reinforced Fly Ash Geopolymer at Elevated Temperatures","volume":"12","author":"Shaikh","year":"2018","journal-title":"Int. J. Concr. Struct. Mater."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"47","DOI":"10.1016\/j.proeng.2016.01.078","article-title":"Experimental Study on High Temperature Properties of Carbon Fiber Sheets Strengthened Concrete Cylinders Using Geopolymer as Adhesive","volume":"135","author":"Zhang","year":"2016","journal-title":"Procedia Eng."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"733","DOI":"10.1016\/j.conbuildmat.2017.11.109","article-title":"Microstructure and mechanical properties of carbon microfiber reinforced geopolymers at elevated temperatures","volume":"160","author":"Behera","year":"2018","journal-title":"Constr. Build. Mater."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"850","DOI":"10.1016\/j.conbuildmat.2017.12.152","article-title":"Elevated temperature properties of basalt microfibril filled geopolymer composites","volume":"163","author":"Behera","year":"2018","journal-title":"Constr. Build. Mater."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1190","DOI":"10.1016\/j.conbuildmat.2018.08.062","article-title":"High-temperature behavior and mechanical characteristics of boron waste additive metakaolin based geopolymer composites reinforced with synthetic fibers","volume":"187","author":"Celik","year":"2018","journal-title":"Constr. Build. Mater."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.compositesb.2013.01.013","article-title":"Characterisation of cotton fibre-reinforced geopolymer composites","volume":"50","author":"Alomayri","year":"2013","journal-title":"Compos. Part B Eng."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"14019","DOI":"10.1016\/j.ceramint.2014.05.128","article-title":"Mechanical and thermal properties of ambient cured cotton fabric-reinforced fly ash-based geopolymer composites","volume":"40","author":"Alomayri","year":"2014","journal-title":"Ceram. Int."},{"key":"ref_17","first-page":"389","article-title":"Influence of Elevated Temperatures on the Mechanical Behavior of Jute-Textile-Reinforced Geopolymers","volume":"8","author":"Alcamand","year":"2017","journal-title":"J. Ceram. Sci. Technol."},{"key":"ref_18","first-page":"e00673","article-title":"Effect of elevated temperatures on mechanical properties of lightweight geopolymer concrete","volume":"15","author":"Tayeh","year":"2021","journal-title":"Case Stud. Constr. Mater."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"231","DOI":"10.1007\/s41062-021-00595-w","article-title":"A comparative review on foam-based versus lightweight aggregate-based alkali-activated materials and geopolymer","volume":"6","author":"Nodehi","year":"2021","journal-title":"Innov. Infrastruct. Solut."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"012051","DOI":"10.1088\/1755-1315\/822\/1\/012051","article-title":"A Review of Geopolymer Composite Thermal Properties","volume":"822","author":"Ali","year":"2021","journal-title":"IOP Conf. Ser. Earth Environ. Sci."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"45355","DOI":"10.1038\/srep45355","article-title":"Thermal Resistance Variations of Fly Ash Geopolymers: Foaming Responses","volume":"7","author":"Hussin","year":"2017","journal-title":"Sci. Rep."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"103886","DOI":"10.1016\/j.cemconcomp.2020.103886","article-title":"Progress, current thinking and challenges in geopolymer foam concrete technology","volume":"116","author":"Dhasindrakrishna","year":"2021","journal-title":"Cem. Concr. Compos."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1016\/j.cemconcomp.2015.03.013","article-title":"Mechanical, thermal insulation, thermal resistance and acoustic absorption properties of geopolymer foam concrete","volume":"62","author":"Zhang","year":"2015","journal-title":"Cem. Concr. Compos."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"5115","DOI":"10.1016\/j.ceramint.2017.01.025","article-title":"Novel thermal insulating and lightweight composites from metakaolin geopolymer and polystyrene particles","volume":"43","author":"Duan","year":"2017","journal-title":"Ceram. Int."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"175","DOI":"10.4028\/www.scientific.net\/SSP.281.175","article-title":"The Mechanical Properties and Thermal Resistance of Fly Ash Geopolymer Foams","volume":"281","author":"Teng","year":"2018","journal-title":"Solid State Phenom."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1515\/secm-2020-0013","article-title":"Mechanical properties of geopolymer foam at high temperature","volume":"27","author":"Le","year":"2020","journal-title":"Sci. Eng. Compos. Mater."},{"key":"ref_27","unstructured":"PN-EN 1008:2017 (2022, March 25). Mixing Water for Concrete\u2014Specification for Sampling, Testing and Assessing the Suitability of Water, Including Water Recovered from Processes in the Concrete Industry, As Mixing Water for Concrete. (In Polish)."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"04018397","DOI":"10.1061\/(ASCE)MT.1943-5533.0002610","article-title":"Lightweight alkali-activated material from mining and glass waste by chemical and physical Foaming","volume":"31","author":"Kastiukas","year":"2019","journal-title":"J. Mater. Civ. Eng."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Szechy\u0144ska-Hebda, M., Marczyk, J., Ziejewska, C., Hordy\u0144ska, N., Miku\u0142a, J., and Hebda, M. (2019). Optimal design of pH-neutral geopolymer foams for their use in ecological plant cultivation systems. Materials, 12.","DOI":"10.3390\/ma12182999"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"841","DOI":"10.1617\/s11527-006-9203-z","article-title":"Recommendation of RILEM TC 200-HTC: Mechanical concrete properties at high temperatures-modelling and applications: PGeneral presentation","volume":"40","author":"Schneider","year":"2007","journal-title":"Mater. Struct. Constr"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"128168","DOI":"10.1016\/j.jclepro.2021.128168","article-title":"Fly-ash based geopolymer mortar for high-temperature application\u2014Effect of slag addition","volume":"316","author":"Hager","year":"2021","journal-title":"J. Clean. Prod."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Dudek, M., and Sitarz, M. (2020). Analysis of changes in the microstructure of geopolymer mortar after exposure to high temperatures. Materials, 13.","DOI":"10.3390\/ma13194263"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Hager, I., Sitarz, M., and Mr\u00f3z, K. (2020, January 23\u201326). Behaviour of fly ash geopolymer at high temperature. Proceedings of the 2020 5th International Conference on Smart and Sustainable Technologies (SpliTech), Split, Croatia.","DOI":"10.23919\/SpliTech49282.2020.9243812"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"945","DOI":"10.1007\/s10694-012-0320-7","article-title":"Colour change in heated concrete","volume":"50","author":"Hager","year":"2014","journal-title":"Fire Technol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"102149","DOI":"10.1016\/j.mtcomm.2021.102149","article-title":"Effect of hydrogen peroxide and bagasse ash additions on thermal conductivity and thermal resistance of geopolymer foams","volume":"26","author":"Pantongsuk","year":"2021","journal-title":"Mater. Today Commun."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"824","DOI":"10.1007\/s10853-007-2205-6","article-title":"Factors affecting the performance of metakaolin geopolymers exposed to elevated temperatures","volume":"43","author":"Kong","year":"2008","journal-title":"J. Mater. Sci."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"431","DOI":"10.37358\/RC.19.2.6929","article-title":"Alkali Activated Mortars with Intumescent Properties","volume":"70","author":"Nicoara","year":"2019","journal-title":"Rev. Chim."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"106649","DOI":"10.1016\/j.cemconres.2021.106649","article-title":"Degradation mechanism of hybrid fly ash\/slag based geopolymers exposed to elevated temperatures","volume":"151","author":"Luo","year":"2022","journal-title":"Cem. Concr. Res."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"125709","DOI":"10.1016\/j.conbuildmat.2021.125709","article-title":"Thermal stability of geopolymer modified by different silicon source materials prepared from solid wastes","volume":"315","author":"Liu","year":"2022","journal-title":"Constr. Build. Mater."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1016\/j.matdes.2018.05.023","article-title":"Effect of alkali cation type on strength endurance of fly ash geopolymers subject to high temperature exposure","volume":"154","author":"Lahoti","year":"2018","journal-title":"Mater. Des."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"21017","DOI":"10.1039\/D1RA02671B","article-title":"Analysis of sodium generation by sodium oxide decomposition on corrosion resistance materials: A new approach towards sodium redox water-splitting cycle","volume":"11","author":"Kumara","year":"2021","journal-title":"RSC Adv."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"5535","DOI":"10.3390\/su6095535","article-title":"A Sustainable Approach for the Geopolymerization of Natural Iron-Rich Aluminosilicate Materials","volume":"6","author":"Obonyo","year":"2014","journal-title":"Sustainability"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"11330","DOI":"10.1016\/j.ceramint.2021.12.356","article-title":"Effect of low-rate firing on physico-mechanical properties of unfoamed and foamed geopolymers prepared from waste clays","volume":"48","author":"Zawrah","year":"2022","journal-title":"Ceram. Int."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"7655","DOI":"10.1016\/j.jmrt.2020.05.034","article-title":"Effects of high-temperature exposure on fractal dimension of fly-ash-based geopolymer composites","volume":"9","author":"Choi","year":"2020","journal-title":"J. Mater. Res. Technol."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"126529","DOI":"10.1016\/j.conbuildmat.2022.126529","article-title":"Thermal and fire resistance of Class F fly ash based geopolymers\u2014A review","volume":"323","author":"Klima","year":"2022","journal-title":"Constr. Build. Mater."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"3440","DOI":"10.1111\/jace.14902","article-title":"Geopolymer foams obtained by the saponification\/peroxide\/gelcasting combined route using different soap foam precursors","volume":"100","author":"Cilla","year":"2017","journal-title":"J. Am. Ceram. Soc."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"121998","DOI":"10.1016\/j.matchemphys.2019.121998","article-title":"In-situ formation of geopolymer foams through addition of silica fume: Preparation and sinterability","volume":"239","author":"Zawrah","year":"2020","journal-title":"Mater. Chem. Phys."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"817","DOI":"10.1111\/ijac.13681","article-title":"Effect of high temperature on the mechanical properties of hierarchical porous cenosphere\/geopolymer composite foams","volume":"18","author":"Yan","year":"2021","journal-title":"Int. J. Appl. Ceram. Technol."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"7196","DOI":"10.1016\/j.ceramint.2018.12.227","article-title":"Waste-to-resource preparation of glass-containing foams from geopolymers","volume":"45","author":"Bai","year":"2019","journal-title":"Ceram. Int."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"2389","DOI":"10.1016\/S0955-2219(03)00631-9","article-title":"Phase transformation and growth of mullite in kaolin ceramics","volume":"24","author":"Chen","year":"2004","journal-title":"J. Eur. Ceram. Soc."},{"key":"ref_51","doi-asserted-by":"crossref","unstructured":"Luhar, S., Nicolaides, D., and Luhar, I. (2021). Fire Resistance Behaviour of Geopolymer Concrete: An Overview. Buildings, 11.","DOI":"10.3390\/buildings11030082"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"113","DOI":"10.1016\/j.conbuildmat.2014.01.081","article-title":"Geopolymer foam concrete: An emerging material for sustainable construction","volume":"56","author":"Zhang","year":"2014","journal-title":"Constr. Build. 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