Mechanical properties of eco-friendly one-part metakaolin-based geopolymer concrete with Recycled Glass and Plastic (RESIN8) aggregates

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dc.contributor.advisorBabafemi, Adewumi Johnen_ZA
dc.contributor.authorAjayi, Babatunde Lukeen_ZA
dc.contributor.otherStellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.en_ZA
dc.date.accessioned2023-11-11T15:31:54Zen_ZA
dc.date.accessioned2024-01-08T15:38:06Zen_ZA
dc.date.available2023-11-11T15:31:54Zen_ZA
dc.date.available2024-01-08T15:38:06Zen_ZA
dc.date.issued2023-11en_ZA
dc.descriptionThesis (MEng)--Stellenbosch University, 2023.en_ZA
dc.description.abstractENGLISH ABSTRACT: The high demand for concrete in the construction industry is directly proportional to the demand for Portland cement (PC), which is the binding agent in concrete. However, PC production leads to the emission of its equivalent amount of carbon dioxide (CO2), resulting in global warming. Consequently, a one-part "just add water" geopolymer binder is developed, which is a potential sustainable binder that could substitute PC. Therefore, this study investigates and reports the mechanical performance, microstructural properties, and cost analysis of a one-part metakaolin-based geopolymer concrete (GPC) produced with anhydrous sodium silicate, sodium hydroxide, and calcium hydroxide as alkali reagents. The GPC materials were pretreated and investigated to assess their physical properties (such as water absorption, particle gradation, specific gravity, and moisture content of the aggregates) and the chemical composition and morphology of the precursors. The optimum GPC mix design was obtained using the Taguchi experimental design approach, and the materials were dry-mixed before water was added. Further, the natural sand was substituted by fine waste aggregate (FWG) and RESIN8 (recycled plastic waste containing Resins 1–7), respectively, at a 5% and 10% replacement level. The influence of the recycled aggregates on the fresh and hardened properties of the composite was investigated and reported. Furthermore, the effects of different curing methods, such as climate-controlled curing (CC), water-curing (WC), and ambient-curing (AC) conditions, were investigated on the compressive strength. The samples tested for splitting tensile and flexural strength were subjected to AC conditions. Adding 5% and 10% of FWG and RESIN8 as fine aggregate in concrete enhances its workability. However, the compressive strength of samples with 5% and 10% RESIN8 is reduced by 15.1% and 19% for CC, 15.7% and 24.1% for AC, and 14.7% and 22% for WC, respectively, compared to their respective control GPC samples after 28 days of curing. On the other hand, the addition of 5% FWG improved the performance of the matrices by 8.9%, 3.5%, and 5.3% for CC, AC, and WC, respectively. After 28 days of curing, the strength of CC sample was increased by 13.6% due to the addition of 10% FWG. In contrast, the strength of AC and WC samples decreased by 0.7% and 1.7%, respectively, when compared to the control GPC samples. The compressive strength of AC samples shows a 10.9% improvement, whereas WC samples show a 16.3% improvement compared to the 28-day CC GPC samples. Further, the compressive strength of CC GPC declined after 28 days of curing; hence, the choice of curing condition greatly influences the performance of GPC. The enhanced strength of the AC and WC samples can be attributed to the presence of water within the concrete matrix, which allows for a complete geopolymerisation reaction. In contrast, the CC sample only underwent hydration due to the consistent curing temperature of 24 °C. The inclusion of 5% and 10% RESIN8 led to a 60.6% and 78% reduction, respectively, in the elastic modulus (E-mod) of GPC, while 5% and 10% FWG inclusion led to a 21.2% and 30.3% reduction in the E-mod of 28-day AC GPC, respectively. Using 5% and 10% FWG reduced the cost of GPC by 0.13% and 0.27%, respectively, while 5% and 10% RESIN8 increased the cost by 0.07% and 0.13%, respectively. The increased cost of RESIN8 containing GPC is due to the high cost of producing RESIN8. Conclusively, structural GPC is obtained, and 5% RESIN8 content and up to 10% FWG content have the potential to substitute natural sand in an environmentally friendly one-part metakaolin-based structural GPC. In contrast, 10% RESIN8 could be used for a non-structural concrete component. The use of RESIN8 and FWG in GPC possesses economic benefits and is a viable solution to environmental pollution, protection of aquatic lives and preservation of natural aggregates.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Die hoë aanvraag vir beton in die konstruksiebedryf is direk eweredig aan die aanvraag vir Portland sement (PC), wat die bindmiddel in beton is. PC-produksie lei egter tot die vrystelling van sy ekwivalente hoeveelheid koolstofdioksied (CO2), wat tot aardverwarming lei. Gevolglik is 'n een-deel "voeg net water by" geopolimeer bindmiddel ontwikkel, wat 'n potensiële volhoubare bindmiddel is wat PC kan vervang. Daarom ondersoek en rapporteer hierdie studie die meganiese werkverrigting, mikrostrukturele eienskappe en koste-analise van 'n eendelige metaolien-slak-gebaseerde geopolimeerbeton (GPC) wat met watervrye natriumsilikaat, natriumhidroksied en kalsiumhidroksied as alkali-reagense vervaardig word. Die GPC-materiale is vooraf behandel en ondersoek om hul fisiese eienskappe (soos waterabsorpsie, deeltjiegradasie, soortlike gewig en voginhoud van die aggregate) en die chemiese samestelling en morfologie van die voorlopers te bepaal. Die optimale GPC-mengselontwerp is verkry deur gebruik te maak van die Taguchi eksperimentele ontwerpbenadering, en die materiale is droog gemeng voordat water bygevoeg is. Verder is die natuurlike sand vervang met fyn afvalaggregaat (FWG) en RESIN8 (herwonne plastiekafval wat Harse 1–7 bevat), onderskeidelik, teen 'n 5% en 10% vervangingsvlak. Die invloed van die herwonne aggregate op die vars en geharde eienskappe van die komposiet is ondersoek en gerapporteer. Verder is die effekte van verskillende uithardingsmetodes, soos klimaatbeheerde uitharding (CC), water-uitharding (WC), en omgewingsuitharding (AC) toestande, op die druksterkte ondersoek. Die monsters wat getoets is vir skeur trek- en buigsterkte is aan AC toestande onderwerp. Die byvoeging van 5% en 10% van FWG en RESIN8 as fyn aggregaat in beton verhoog die werkbaarheid daarvan. Die druksterkte van monsters met 5% en 10% RESIN8 word egter verminder met 15.1% en 19% vir CC, 15.7% en 24.1% vir AC, en 14.7% en 22% vir WC, onderskeidelik, in vergelyking met hul onderskeie kontrole GPC monsters na 28 dae van uitharding. Aan die ander kant het die byvoeging van 5% FWG die prestasie van die matrikse met onderskeidelik 8.9%, 3.5% en 5.3% vir CC, AC en WC verbeter. Na 28 dae van uitharding, is die sterkte van CC monster met 13.6% verhoog as gevolg van die byvoeging van 10% FWG. Daarteenoor het die sterkte van AC- en WC-monsters met 0.7% en 1.7% onderskeidelik afgeneem in vergelyking met die kontrole GPC-monsters. Die druksterkte van AC monsters toon 'n 10.9% verbetering, terwyl WC monsters 'n 16.3% verbetering toon in vergelyking met die 28-dae CC GPC monsters. Verder het die druksterkte van CC GPC na 28 dae van uitharding afgeneem; gevolglik beïnvloed die keuse van uithardingstoestand die werkverrigting van GPC grootliks. Die verhoogde sterkte van die AC- en WC-monsters kan toegeskryf word aan die teenwoordigheid van water binne die betonmatriks, wat 'n volledige geopolimerisasie-reaksie moontlik maak. Daarteenoor het die CC-monster slegs hidrasie ondergaan as gevolg van die konstante uithardingstemperatuur van 24 °C. Die insluiting van 5% en 10% RESIN8 het tot 'n vermindering van onderskeidelik 60.6% en 78% in die elastiese modulus (E-mod) van GPC gelei, terwyl 5% en 10% FWG-insluiting tot 'n vermindering van 21.2% en 30.3%. in die E-mod van 28-dag AC GPC gelei het, onderskeidelik. Die gebruik van 5% en 10% FWG het die koste van GPC met onderskeidelik 0.13% en 0.27% verminder, terwyl 5% en 10% RESIN8 die koste met onderskeidelik 0.07% en 0.13% verhoog het. Die verhoogde koste van RESIN8 wat GPC bevat, is as gevolg van die hoë koste van die vervaardiging van RESIN8. Ten slotte, strukturele GPC is verkry, en 5% RESIN8 inhoud en tot 10% FWG inhoud het die potensiaal om natuurlike sand te vervang in 'n omgewingsvriendelike een-deel metakaolin-gebaseerde strukturele GPC. Daarteenoor kan 10% RESIN8 gebruik word vir 'n nie-strukturele beton komponent. Die gebruik van RESIN8 en FWG in GPC hou ekonomiese voordele in en is 'n lewensvatbare oplossing vir omgewingsbesoedeling, beskerming van waterlewe en bewaring van natuurlike aggregate.af_ZA
dc.description.versionMastersen_ZA
dc.format.extentxvii, 31 pages : Illustrationsen_ZA
dc.identifier.urihttps://scholar.sun.ac.za/handle/10019.1/128914
dc.language.isoen_ZAen_ZA
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subject.lcshConcrete construction industryen_ZA
dc.subject.lcshPortland cement -- Additivesen_ZA
dc.subject.lcshReinforced concrete -- Mechanical propertiesen_ZA
dc.subject.lcshInorganic polymersen_ZA
dc.subject.lcshMaterials -- Mechanical propertiesen_ZA
dc.titleMechanical properties of eco-friendly one-part metakaolin-based geopolymer concrete with Recycled Glass and Plastic (RESIN8) aggregatesen_ZA
dc.typeThesisen_ZA
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