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Optimised mix composition and structural behaviour of Ultra-High-Performance Fibre Reinforced Concrete
Dissertation (MEng)--University of Pretoria, 2020.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2020
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| _version_ | 1867613500191277056 |
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| access_status_str | Open Access |
| author2 | Kearsley, Elsabe P. |
| author_browse | Kearsley, Elsabe P. |
| author_facet | Kearsley, Elsabe P. |
| collection | Thesis |
| dc_rights_str_mv | © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MEng)--University of Pretoria, 2020. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/73097 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:08.061Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2020 |
| publishDateRange | 2020 |
| publishDateSort | 2020 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/73097 Optimised mix composition and structural behaviour of Ultra-High-Performance Fibre Reinforced Concrete Kearsley, Elsabe P. meganweyers@icloud.com Weyers, Megan Ultra-High-Performance Fibre Reinforced Concrete (UHPFRC) Modified Andreasen and Andersen Particle Packing Model Response Surface Design Methodology Tensile stress-strain relationship of UHPC Specimen size effect Ultra-High-Performance Concrete (UHPC) UCTD Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-11 SDG-11: Sustainable cities and communities Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Dissertation (MEng)--University of Pretoria, 2020. The overall objective of this study was to develop an optimised Ultra-High-Performance Concrete (UHPC) matrix based on the modified Andreasen and Andersen optimum particle packing model by using available South African materials. The focus of this study was to determine the optimum combined fibre and superplasticiser content for UHPC by using a response surface design. The UHPC was appropriately designed, produced and tested. Various changes in mechanical properties resulting from different combinations of steel fibre and superplasticiser contents was investigated. The flowability, density and mechanical properties of the designed UHPC were measured and analysed. Both the fibre and superplasticiser content play a significant role in the flowability of the fresh concrete. The addition of fibres significantly improved the strength of the concrete. The results show that the superplasticiser content can be increased if a more workable mix is required without decreasing the strength significantly. The statistical analysis of the response surface methodology confirms that the designed models can be used to navigate the design space defined by the Central Composite Design. The optimum combined fibre and superplasticiser content depend on the required mechanical properties and cost. Using the modified Andreasen and Andersen particle packing model and surface response design methodology, it is possible to efficiently produce a dense Ultra-High-Performance Fibre Reinforced Concrete (UHPFRC) with a relatively low binder amount, low fibre content and good workability. The effect of heat curing on the mechanical properties was investigated. It was concluded that heat curing is not recommended when considering the long-term strength development. The estimated strength development of concrete obtained by using the fib Model Code 2010 (2013) does not incorporate the detrimental effect of high curing temperatures on long-term strength and therefore overestimate the long-term strengths. The strength estimates for both early and long-term ages can be improved by considering this effect in the strength development functions obtained from fib Model Code 2010 (2013). The effect of specimen size on the compressive and flexural tensile strength of UHPFRC members were established. It was found that the specimen size has a significant effect on the measured cube compressive strength. Smaller beam specimens showed higher ductility compared to those of the larger beam specimens. The crack width decreased as the beam’s depth decreased. A lower variability was experienced in the beams with limited depth (< 45 mm). Further testing is required to determine whether a span-to-depth ratio of 10 would yield optimum results. The utilisation of by-products, such as undensified silica fume and fly ash, as cement replacement materials makes UHPFRC sustainable, leading to a reduced life-cycle cost. The calculated Embodied Energy per unit strength (EE/unit strength) and Embodied Carbon per unit strength (EC/unit strength) values for the UHPFRC mixture yield lower values compared to that of the 30 MPa concrete mixture, indicating that UHPFRC can be used to reduce the environmental footprint of the concrete industry. The inverse analysis method used was successful in providing an improved simplified stress-strain response for the UHPFRC. The analysis provided valuable information into the stress-strain, load-deflection and moment-curvature responses of the UHPFRC. Standard material test results were used to theoretically calculate moment-curvature responses and were then compared to the experimental results obtained. The study demonstrated that it is possible to efficiently produce a dense and workable UHPFRC with relatively low binder amount and low fibre content. This can result in more cost-effective UHPFRC, thus improving the practical application thereof. Civil Engineering MEng (Structural engineering) Unrestricted 2020-02-04T10:08:37Z 2020-02-04T10:08:37Z 2020-05 2020 Dissertation Weyers, M 2020, Optimised mix composition and structural behaviour of Ultra-High-Performance Fibre Reinforced Concrete, MEng (Structural engineering) Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/73097> A2020 http://hdl.handle.net/2263/73097 en © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | Ultra-High-Performance Fibre Reinforced Concrete (UHPFRC) Modified Andreasen and Andersen Particle Packing Model Response Surface Design Methodology Tensile stress-strain relationship of UHPC Specimen size effect Ultra-High-Performance Concrete (UHPC) UCTD Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-11 SDG-11: Sustainable cities and communities Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Optimised mix composition and structural behaviour of Ultra-High-Performance Fibre Reinforced Concrete |
| title | Optimised mix composition and structural behaviour of Ultra-High-Performance Fibre Reinforced Concrete |
| title_full | Optimised mix composition and structural behaviour of Ultra-High-Performance Fibre Reinforced Concrete |
| title_fullStr | Optimised mix composition and structural behaviour of Ultra-High-Performance Fibre Reinforced Concrete |
| title_full_unstemmed | Optimised mix composition and structural behaviour of Ultra-High-Performance Fibre Reinforced Concrete |
| title_short | Optimised mix composition and structural behaviour of Ultra-High-Performance Fibre Reinforced Concrete |
| title_sort | optimised mix composition and structural behaviour of ultra high performance fibre reinforced concrete |
| topic | Ultra-High-Performance Fibre Reinforced Concrete (UHPFRC) Modified Andreasen and Andersen Particle Packing Model Response Surface Design Methodology Tensile stress-strain relationship of UHPC Specimen size effect Ultra-High-Performance Concrete (UHPC) UCTD Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-11 SDG-11: Sustainable cities and communities Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production |
| url | http://hdl.handle.net/2263/73097 |