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Fire behaviour of construction systems incorporating biomass and recycled materials
Thesis (PhD)--Stellenbosch University, 2024.
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867613764072767488 |
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| access_status_str | Open Access |
| author | Shewalul, Yohannes Werkina |
| author2 | Walls, Richard Shaun |
| author_browse | Shewalul, Yohannes Werkina Walls, Richard Shaun |
| author_facet | Walls, Richard Shaun Shewalul, Yohannes Werkina |
| author_sort | Shewalul, Yohannes Werkina |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description |
Thesis (PhD)--Stellenbosch University, 2024. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/131905 |
| institution | Stellenbosch University (South Africa) |
| last_indexed | 2026-06-10T12:41:19.685Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/131905 Fire behaviour of construction systems incorporating biomass and recycled materials Shewalul, Yohannes Werkina Walls, Richard Shaun Quiroz, Natalia Flores Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering. Building, Fireproof Biomass -- Combustion Sustainable buildings -- Materials Building materials -- Thermal properties UCTD Thesis (PhD)--Stellenbosch University, 2024. ENGLISH ABSTRACT: Recent developments in construction systems has seen incorporation of sustainable biomass and recycled materials into building systems. However, such materials are often combustible, may produce toxic fumes during fires, and their fire characteristics are not well established. These factors can influence the safety of occupants, building performance, fire dynamics, and firefighting strategies. This dissertation investigates and quantifies the fire behaviour of construction systems incorporating combustible biomass (hemp-based materials) and recycled waste materials (crumb rubber and plastic eco-aggregates). Experimental testing conducted on these materials includes laboratory scale tests, reaction-to-fire tests, fire resistance tests, and elevated temperature material tests, along with numerical heat transfer modelling. Fire phenomena and properties such as thermal decomposition, phase changes, heat release rates (HRRs), mass loss rate (MLR), smoke production, ignition parameters, fire thermal hazard parameters, heat of combustion, charring, structural stability, integrity, insulation, temperature distributions, load-bearing capacity, and mechanical strength at elevated temperature have been obtained through various tests. Thermal properties such as thermal conductivity and specific heat are determined from heat transfer analyses developed based on experimental tests. The results highlight that hemp blocks do not ignite and exhibit low HRR (around one tenth of virgin hemp). Charring and smouldering combustion are important phenomena that may need to be considered. They are likely to have a limited impact on fire risk in buildings. Pure crumb rubber and recycled plastic aggregate (RESIN8) exhibit high combustibility, easy ignitability, rapid decomposition, and substantial smoke production, classifying them as a high thermal fire hazard and posing a potential fire risk. Replacement values of such materials within sustainable concrete bricks (SCBs) considered in this dissertation range 0% to 50%. Higher replacement rates in SCBs lead to ignition and flaming, with significant heat release rates and smoke production, while lower replacement rates may only result in smouldering and smoke production. Both hemp blocks and SCB samples exhibit significant strength loss under various elevated temperature exposures. Hemp blocks have negligible strength by around 300°C, while SCBs with a 50% replacement level shows explosive spalling at temperatures over 600°C. Non-load bearing hemp walls and concrete masonry walls can withstand standard fire exposure for 2 h without forming cracks or holes, also meeting insulation criteria. Numerical modelling, using a heat transfer analysis approach, was used to effectively predict the thermal properties of these systems. The results can be further used in performance-based fire design and for various similar construction systems. This dissertation will aid regulatory bodies in updating building codes and fire safety regulations of these construction systems. Additionally, it supports the use of biomass and recycled materials by reducing dependence on conventional, less sustainable materials, whilst highlighting areas where fire safety may be impacted. AFRIKAANSE OPSOMMING: Onlangse ontwikkelings in boustrukture het die inkorporering van volhoubare biomassa en herwinde materiale in boustelsels gesien. Sulke materiale is egter dikwels brandbaar, kan giftige rook tydens brande produseer, en hul brand eienskappe is nie goed gevestig nie. Hierdie faktore kan die veiligheid van bewoners, gebouprestasie, branddinamika en blusstrategieë beïnvloed. Hierdie proefskrif ondersoek en kwantifiseer die brandgedrag van boustrukture wat brandbare biomassa (henep-gebaseerde materiale) en herwinde afvalmateriale (krummelrubber en plastiek-eko-agregate) bevat. Eksperimentele toetsing op hierdie materiale sluit laboratoriumskaal toetse, reaksie-op-brand toetse, brandweerstand toetse en verhoogde temperatuur materiaal toetse in, tesame met numeriese hitte-oordrag modellering. Brandverskynsels en eienskappe soos termiese ontbinding, faseveranderings, hittevrywaringstempo's (HRRs), massaverliestempo (MLR), rookproduksie, ontbrandingsparameters, brandtermiese gevaarparameters, verbrandingshitte, verskroeing, strukturele stabiliteit, integriteit, isolasie, temperatuurverdelings, dravermoë, en meganiese sterkte by verhoogde temperatuur is verkry deur verskeie toetse. Termiese eienskappe soos termiese geleidbaarheid en spesifieke hitte word bepaal uit hitte-oordrag analises ontwikkel op grond van eksperimentele toetse. Die resultate beklemtoon dat hennepblokke nie ontbrand nie en lae HRR (ongeveer een tiende van maagdelike hennep) vertoon. Verskroeing en smeulende verbranding is belangrike verskynsels wat in ag geneem moet word. Hulle sal waarskynlik 'n beperkte impak op die brandrisiko in geboue hê. Suiwer krummelrubber en herwinde plastiek-agregaat (RESIN8) vertoon hoë brandbaarheid, maklike ontbranding, vinnige ontbinding en aansienlike rookproduksie, wat hulle klassifiseer as 'n hoë termiese brandgevaar en 'n potensiële brandrisiko inhou. Vervangingswaardes van sulke materiale binne volhoubare betonstene (SCBs) wat in hierdie proefskrif beskou word, wissel van 0% tot 50%. Hoër vervangingsvlakke in SCBs lei tot ontbranding en vlamme, met beduidende hittevrywaringstempo's en rookproduksie, terwyl laer vervangingsvlakke slegs tot smeuling en rookproduksie kan lei. Beide hennepblokke en SCBmonsters toon beduidende sterkteverlies onder verskillende verhoogde temperatuur blootstellings. Hennepblokke het weglaatbare sterkte teen ongeveer 300 ° C, terwyl SCBs met 'n 50% vervangingsvlak eksplosiewe afskilfering toon by temperature bo 600 ° C. Nie-lasdraende hennepmure en betonmassiefmure kan standaard brandblootstelling vir 2 uur weerstaan sonder om krake of gate te vorm, en voldoen ook aan isolasie-kriteria. Numeriese modellering, met behulp van 'n hitte-oordrag analise benadering, is gebruik om die termiese eienskappe van hierdie stelsels effektief te voorspel. Die resultate kan verder gebruik word in prestasie-gebaseerde brandontwerp en vir verskeie soortgelyke boustrukture. Hierdie proefskrif sal regulerende liggame help om boukodes en brandveiligheidsregulasies van hierdie boustrukture op te dateer. Boonop ondersteun dit die gebruik van biomassa en herwinde materiale deur afhanklikheid van konvensionele, minder volhoubare materiale te verminder, terwyl areas waar brandveiligheid beïnvloed kan word, beklemtoon word. Doctoral 2025-04-08T09:47:25Z 2025-04-08T09:47:25Z 2024-12 Thesis https://scholar.sun.ac.za/handle/10019.1/131905 Stellenbosch University xix, 157 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Building, Fireproof Biomass -- Combustion Sustainable buildings -- Materials Building materials -- Thermal properties UCTD Shewalul, Yohannes Werkina Fire behaviour of construction systems incorporating biomass and recycled materials |
| title | Fire behaviour of construction systems incorporating biomass and recycled materials |
| title_full | Fire behaviour of construction systems incorporating biomass and recycled materials |
| title_fullStr | Fire behaviour of construction systems incorporating biomass and recycled materials |
| title_full_unstemmed | Fire behaviour of construction systems incorporating biomass and recycled materials |
| title_short | Fire behaviour of construction systems incorporating biomass and recycled materials |
| title_sort | fire behaviour of construction systems incorporating biomass and recycled materials |
| topic | Building, Fireproof Biomass -- Combustion Sustainable buildings -- Materials Building materials -- Thermal properties UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/131905 |
| work_keys_str_mv | AT shewalulyohanneswerkina firebehaviourofconstructionsystemsincorporatingbiomassandrecycledmaterials |