Physico-chemical interventions for improved interlayer adhesion in 3D printable concrete.

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dc.contributor.advisorVan Zijl, Gideon P. A. G.en_ZA
dc.contributor.advisorKruger, Jacquesen_ZA
dc.contributor.advisorStellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.en_ZA
dc.contributor.authorMunemo, Ruvimbo Eustinaen_ZA
dc.date.accessioned2024-02-27T16:42:39Zen_ZA
dc.date.accessioned2024-04-26T19:28:22Zen_ZA
dc.date.available2024-02-27T16:42:39Zen_ZA
dc.date.available2024-04-26T19:28:22Zen_ZA
dc.date.issued2024-03en_ZA
dc.descriptionThesis (PhD)--Stellenbosch University, 2024.en_ZA
dc.description.abstractENGLISH ABSTRACT: 3D concrete printing (3DCP), a revolutionary additive manufacturing (AM) technique, has the potential to transform the construction industry. It is an advantageous technique that offers more geometric freedom while simultaneously promising resource efficiency and enhanced productivity. However, due to the layer-based intrinsic nature of ANL the lack of interlayer adhesion (IA) is a prevalent issue that significantly impacts the mechanical performance of printed structures. Although the mechanism leading to lack of IA between filament layer in 3D printable concrete (3DPC) have been investigated in literature, the synergistic and antagonistic nature of these mechanism• is rarely considered Weak adhesion bet-ween filament layers undermines the inherently advantageous properties of 3DPC, as well as those of the fabrication process. Therefore, to address this issue, this research endeavors to ascertain physico-chemical interventions to bolster IA between 3DPC filaments which do not impede the fabrication process. An extensive review of methods that have been Implemented to enhance interlayer bond strength (IBS) is conducted to elucidate beneficial characteristics and strategies that yield the most desirable IA. Furthermore, strategies employed for modelling the interlayer region (IR) are analysed and used as the foundation for determining ruling parameters in simulation of IBS. Subsequently, a rubric for selection and assessment of effectiveness of an intervention strategy is proposed. The principal selection criterion is that an intervention must enhance IA by leveraging intrinsic properties of 3DPC without hampering the efficiency of the fabrication process. Each intervention IS mechanically and microstructurally characterized and the mechanisms leading to IA enhancement are investigated Two interventions are proposed and implemented Both strategies are novel to the 3DCP industry but show great promise and reliability with a low degree of complexity in both accessibility and implementation. The first intervention, characterised by induction of thermo-hydrokinetics to improve surface malleability and moisture content through the incorporation of a short-lived localised burst of steam on the surface of the preceding filament layer prior to placement of the subsequent filament layer, is presented and rigorously tested to assess the Improvement in IA. The IBS is bolstered by 78 0/0. The Intervention is then evaluated against the pre-set criteria to validate whether it is viable technique for enhancing IBS. The behavior induced by this intervention leading to better IA is subsequently empirically and computationally modelled and analysed to illuminate the Influencing factors and how they contribute to the enhancement of IA. The proposed empirical model appears to be extendable as it was able to accurately simulate the results of other studies conducted m literature yielding statistically significant findings. The second intervention characterized by silicate impregnation in the IR via interfacial surface treatment, IS also presented and evaluated. It bolstered IBS by 103 0/0, as well as the bonded area, as evidenced by the enlarged failure area. This research is a comprehensive investigation into intervention strategies to mitigate the lack of IA, with proposed interventions that not only yield more robust IRS but are also viable techniques that can be seamlessly Integrated into the fabrication process. The findings encourage a more synergistic approach to ensure strategies amalgamate to create resilient structures.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: 3D-betondmk-werk (3DBD), 'n revolusionére additiewe vewaardigingstegniek (AV), het die potenslaal om die konstmksiebedryf te transformeer. Dlt is 'n voordehge tegniek wat tneer geometnese uyheld bied, tenvyl dit terselfdefiyd hulpbrondoeltreffendheld en verhoogde produHiuiteit belowe_ As gevolg van die laaggebaseerde intnnsieke aard van AV. is die gebrek aan tussenlaaghegting (TLH) egter 'n algemene probleem wat die megamese werkæerrigting van gedmkte stmkture aansienllk bemvloed. Alhoewel die meganlsmes wat lei tot 'n gebrek aan TI_H m 3D-dmkbare beton (3DDB) in die literatuur ondersoek IS, word die sinerglstiese en antagomstiese aard van hlerdle meganismes selde oonveeg_ S'.vü adhesie tussen filament] ae ondermyll die Inherent voordelige eienskappe van 3DDB, sowel as dlé van die vavaardlgingsproses. 0m hierdie kl.vessie aan te spreek, poog hierdie navorsing om fisies-chenuese intervensles vas te stel om TLH tussen 3DDB-fi1amente te versterk wat me die vavaardlgingsproses belenumer nie 'n Uitgebreide oorsig van metodes wat gennplenrnteer is om die tussenlaagbindingsterke (TLBS) te verbeter, word ultgevoer om voorcLe1ige elenskappe en strategiee toe te lig wat die wensmcste TLH lewer. Verder word strateglee wat word die modellering van die tussenlaaggebied (TLG) ontleed en gebmik as die grondslag vy die bepalmg van heersende parameters in sinlulasie van TLBS Velvolgens word 'n rubriek vir seleksie en assessenng van effektnviteit van 'n mtavensiestrategie voorgestel_ Die belangrikste seleksiekriterium is dat 'n ingrypmg TLH moet verbeter deur mtnnsieke eienskappe van 3DDB te benut sonder om die doeltreffendheid van die vavaardlgingsproses te belemmer. Elke intervensie word meganles en nukrostmktureel gekenmerk en die meganismes wat tot TLH-verbetering lei, word ondersoek Twee ingrypmgs word voorgestel en gednplementeer. Albei strategeé is nuut die 3DBD-industne, maar toon groot belone en betroubaarheld Inet 'n lae mate van konmpleksiteit in beide toeganklikheld en Implementering. Die eerste intervensie word gekenmerk word deur induksie van om opperclak smeebaarheld en voginhoud te verbeter. Dlt behels 'n koltstondige gelokaliseerde stoombars op die oppelvlak van die voorafgaande filamentlaag vmr die plasmg van die daaropvolgende filament1aagStreng toetse word uitgevoer om die verbetering m TLH te bepaal. Die mgryping word dan geevalueer aan die hand van die voora%epaalde Iffltena om te bevestig of dit 'n lewensvatbare tegmek is om TLBS te v«beter. Die gedrag wat deur hlerdle intelvensle veroorsaak word wat tot beter TLH word venolgens empiries en berekenend gemodelleer en ontleed om die beinvloedende faktore en hoe hulle bydra tot die verbetenng van TLH toe te lie Die voorgestelde empiriese model blyk uitbreidbaar te wees, aangesien dit die ekspenmentele resultate van ander studies wat in die literatuur uitgevoer is, aldcuraat kon sunuleer en statisties beduldende bevindmgs opgelewer het Die Neede intervensie, gekenmerk deur sflikaatimpregnering m die TLG via interfasiale word 00k aangebied en geevalueer_ Dit versterk TLBS, sowel as die effektief gebonde gebied, soos blyk ult die vergrote falingsom)enrlakte. Hierdie navorsing is 'n omvattende ondersoek na intewensiestrategiee om die gebrek aan TI_H aan te spreek, met voorgestelcLe intervensies wat nie net meer robuuste TLG's oplewer me, maar 00k lewensvatbare tegnieke is wat naatloos in die ver.aardigmgsproses gedltegreer kan word. Die bevindinge moedig 'n meer sinergistlese benadering aan om te verseker dat strategee amalgameer om weerbare stmkture te skep.af_ZA
dc.description.versionMastersen_ZA
dc.format.extentxvi, 183 pages : illustrationsen_ZA
dc.identifier.urihttps://scholar.sun.ac.za/handle/10019.1/130489en_ZA
dc.language.isoen_ZAen_ZA
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subject.lcshThree-dimensional printingen_ZA
dc.subject.lcshConstruction industry -- Technological innovationsen_ZA
dc.subject.lcshAdditive manufacturing -- Automation.en_ZA
dc.subject.lcshInterlayer bond strengthen_ZA
dc.titlePhysico-chemical interventions for improved interlayer adhesion in 3D printable concrete. en_ZA
dc.typeThesisen_ZA
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