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Characterisation and Evaluations of the Mechanical Properties of Alternative Masonry Units

dc.contributor.advisorDe Villiers, Wibkeen_ZA
dc.contributor.authorFourie, Johannesen_ZA
dc.contributor.otherStellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.en_ZA
dc.date.accessioned2017-02-10T13:59:45Z
dc.date.accessioned2017-03-29T11:41:51Z
dc.date.available2017-02-10T13:59:45Z
dc.date.available2017-03-29T11:41:51Z
dc.date.issued2017-03
dc.identifier.urihttp://hdl.handle.net/10019.1/100880
dc.descriptionThesis (MEng)--Stellenbosch University, 2017.en_ZA
dc.description.abstractENGLISH ABSTRACT: One of the greatest challenges facing the South African government is the provision of adequate and affordable housing to the 1.1 million families still living in informal settlements. Currently, the most widely used method of constructing low income housing (LIH) in South Africa is through the use of cement based masonry units. However, it is well known that concrete and cement have a significant negative impact on the environment due to carbon dioxide emissions from the production of cement clinker, as well as the consumption of natural resources. In order to reduce the environmental impacts, alternative masonry units (AMUs) are required that are structurally viable, environmentally friendly and socially acceptable. To properly begin implementing AMUs in practice the evaluation and characterisation of their mechanical properties are necessary. While standardised tests for conventional masonry units are widely available, it is unclear whether these tests are suitable for use on AMUs due to the large differences in the material properties between certain AMUs and conventional masonry units. Few standards exist that have been designed with AMUs in mind. This study investigates whether the standards and guidelines available for conventional masonry units can be applied to AMUs. Three different AMUs are compared with a conventional concrete masonry unit (CMU) in a variety of tests to determine if the applicable standards are successful at classifying the mechanical properties of the AMUs. The AMUs that were chosen for this investigation are: alkali-activated concrete blocks (AACBs), compressed stabilised earth blocks (CSEBs) and adobe blocks. These materials were chosen so that the mechanical properties of each material varied notably from each other and from the CMU. The AMUs and the benchmark CMU were tested for a large variety of mechanical properties. Not only can the results from these tests be used to determine if the standards and guidelines are applicable to both conventional and alternative masonry units, but the data acquired from the investigation can be used in future numerical modelling. The standardised tests and mechanical properties investigated in this study include the following: • Compressive strength of the masonry units at 7, 14, 28, 56 and 91 days. Including both bedface and headface tests at 28 days. • Modulus of elasticity and Poisson’s ratio tests conducted on masonry cylinders. • Wedge splitting tests to determine the fracture energy of the materials. • Constant mass density tests. • Triplet tests to determine the shear behaviour at the interface of the masonry samples. Including both initial shear strength and internal angle of friction. • Compressive strength tests on small scale masonry wallets to determine both the compressive strength and modulus of elasticity. The outcomes of the study showed that the AACBs and CSEBs satisfy the minimum strength requirements for LIH in South Africa, while the adobe blocks were too weak. The weak adobe masonry units caused the most complications during the test procedures, nevertheless, the investigation found that with small adjustments to the standards, particularly the loading procedures, the tests could be successfully completed on the AMUs. Issues were however, encountered with the tests for Poisson’s ratio. The tests also provided a large variety of mechanical properties for both conventional and alternative masonry units which can be used in future studies for the numerical modelling of masonry for low income housing in South Africa. The knowledge gained in this study can therefore be used to begin laying the framework for the minimum technical specifications for AMUs in South Africa.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Een van die grootste uitdagings vir die Suid-Afrikaanse regering is die voorsiening van voldoende en bekostigbare behuising aan die 1,1 miljoen gesinne wat steeds in informele nedersettings woon. Die mees algemeende metode vir die bou van lae-inkomste behuising in Suid-Afrika is met sement gebaseerde boueenhede. Dit is bekend dat beton en sement ’n beduidende negatiewe impak het op die omgewing as gevolg van koolstofdioksiedemissies van die produksie van sement klinkers asook die verbruik van natuurlike hulpbronne. Met die doel om die omgewingsimpak te verminder, is alternatiewe eenhede nodig wat struktureel lewensvatbaar, omgewingsvriendelik en sosiaal aanvaarbaar is. Om behoorlik te begin met die implementering van alternatiewe boueenhede in die praktyk is die evaluering en karakterisering van hul meganiese eienskappe nodig. Terwyl gestandaardiseerde toetse vir konvensionele boueenhede oral beskikbaar is, is dit nie duidelik of hierdie toetse ook geskik is vir gebruik op alternatiewe boueenhede nie as gevolg van die groot verskille in die materiaal eienskappe tussen sekere alternatiewe boueenhede en konvensionele boueenhede. Min standaarde bestaan wat ontwerp is met alternatiewe boueenhede in gedagte. Hierdie studie ondersoek of die standaarde en riglyne vat beskikbaar is vir konvensionele boueenhede gebruik kan word op alternatiewe boueenhede. Drie verskillende alternatiewe boueenhede word vergelyk met ’n konvensionele beton bou eenheid, in ’n verskeidenheid van toetse om te bepaal of die toepaslike standaarde suksesvol is om die meganiese eienskappe van die alternatiewe boueenhede te bepaal. Die alternatiewe boueenhede wat vir hierdie studie gekies is, is: alkaligeaktiveerde betonblokke, saamgeperste gestabiliseerde grondblokke en adobeblokke. Hierdie materiale is gekies sodat die meganiese eienskappe van elke materiaal verskil van mekaar en van die konvensionele betonblokke. Die alternatiewe boueenhede en die maatstaf beton bou eenheid word getoets vir ’n verskeidenheid van meganiese eienskappe. Die resultate van hierdie toetse kan gebruik word om te bepaal of die standaarde en riglyne van toepassing is op beide die konvensionele en alternatiewe boueenhede, en die data kan gebruik word in die toekoms om numeriese modellering to doen. Die gestandaardiseerde toetse en meganiese eienskappe wat ondersoek word in hierdie studie sluit in die volgende: • Druksterkte van die boueenhede op 7, 14, 28, 56 en 91 dae. Insluitend beide bedgesig en hoofgesig toetse op 28 dae. • Elastisiteitsmodulus en Poisson se verhoudingtoetse uitgevoer op boublok silinders • Splyttoetse om die verbrekingsenergie van die materiaal te bepaal. • Konstantemassadigtheids toetse. • ‘Triplet’ toetse om die skuifgedrag by die koppelvlak van die boublok monsters te bepaal. Insluitend beide aanvanklike skuifsterkte en internehoek van wrywing. • Druksterkte toetse op kleinskaal blok mure om beide die druksterkte en elastisiteitsmodulus te bepaal. Die resultate van die studie het getoon dat die alkali-geaktiveerde betonblokke en saamgeperste gestabiliseerde grondblokke voldoen aan die minimum krag vereistes vir lae-inkomste behuising in Suid-Afrika, terwyl die Adobeblokke te swak was. Die baie swak Adobeblokke het die meeste komplikasies veroorsaak tydens die toets prosedures, maar die studie het bevind dat met klein aanpassings aan die standaarde, veral die laai prosedures, kan die toetse suksesvol voltooi word op die alternatiewe boueenhede. Probleme was egter ondervind met die toetse vir Poisson se verhouding. Die toetse het ook ’n groot verskeidenheid van meganiese eienskappe vir beide die konvensionele en alternatiewe boueenhede uitgewys, wat in toekomstige studies kan gebruik word vir die numeriese modellering van boublokke vir lae inkomste behuising in Suid-Afrika. Die kennis wat in hierdie studie opgedoen is, kan dus gebruik word om die raamwerk te lê vir die minimum tegniese spesifikasies van alternatiewe boueenhede in Suid-Afrika.af_ZA
dc.format.extentxvii, 136 pages : illustrationsen_ZA
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.subjectMasonry -- Buildings -- Mechanical propertiesen_ZA
dc.subjectEcological housesen_ZA
dc.subjectConcrete masonryen_ZA
dc.subjectMaterials -- Compression testingen_ZA
dc.subjectAdobe bricken_ZA
dc.subjectAlkali-Activated Materialen_ZA
dc.subjectUCTDen_ZA
dc.titleCharacterisation and Evaluations of the Mechanical Properties of Alternative Masonry Unitsen_ZA
dc.typeThesisen_ZA
dc.rights.holderStellenbosch Universityen_ZA


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