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The structural use of synthetic fibres : thickness design of concrete slabs on grade

Thesis (MScEng)-- Stellenbosch University, 2013.

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Bibliographic Details
Main Author: Bothma, Jacques
Other Authors: Boshoff, William Peter
Format: Thesis
Language:en_ZA
Published: Stellenbosch : Stellenbosch University 2013
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access_status_str Open Access
author Bothma, Jacques
author2 Boshoff, William Peter
author_browse Boshoff, William Peter
Bothma, Jacques
author_facet Boshoff, William Peter
Bothma, Jacques
author_sort Bothma, Jacques
collection Thesis
dc_rights_str_mv Stellenbosch University
description Thesis (MScEng)-- Stellenbosch University, 2013.
format Thesis
id oai:scholar.sun.ac.za:10019.1/85877
institution Stellenbosch University (South Africa)
language en_ZA
last_indexed 2026-06-10T12:44:53.996Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository
publishDate 2013
publishDateRange 2013
publishDateSort 2013
publisher Stellenbosch : Stellenbosch University
publisherStr Stellenbosch : Stellenbosch University
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source_str SUNScholar — Stellenbosch University Repository
spelling oai:scholar.sun.ac.za:10019.1/85877 The structural use of synthetic fibres : thickness design of concrete slabs on grade Bothma, Jacques Boshoff, William Peter Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering. Textile fibres, synthetic Concrete slabs -- Testing Reinforced concrete construction Yield-line analysis Plasticity Dissertations -- Civil engineering Concrete slabs -- Design and construction Theses -- Civil engineering Thesis (MScEng)-- Stellenbosch University, 2013. ENGLISH ABSTRACT: Concrete is used in most of the modern day infrastructure. It is a building material for which there exist various design codes and guidelines for its use and construction. It is strong in compression, but lacks tensile strength in its fresh and hardened states and, when unreinforced, fails in a brittle manner. The structural use of synthetic fibres in concrete is investigated in this study to determine its effect on enhancing the mechanical properties of concrete. Slabs on grade are used as the application for which the concrete is tested. The material behaviour is investigated in parallel with two floor design theories. These are the Westegaard theory and the Yield-Line theory. The Westegaard theory uses elastic theory to calculate floor thicknesses while the Yield-Line theory includes plastic behaviour. Conceptual designs are performed with the two theories and material parameters are determined from flexural tests conducted on synthetic fibre reinforced concrete (SynFRC) specimens. Large scale slab tests are performed to verify design values from the two theories. Higher loads till first-crack were measured during tests with concrete slabs reinforced with polypropylene fibres than for unreinforced concrete. It is found that the use of synthetic fibres in concrete increases the post-crack ductility of the material. The Westegaard theory is conservative in its design approach by over-estimating design thicknesses. This was concluded as unreinforced slabs reached higher failure loads than predicted by this theory. The Yield-Line theory predicts design thicknesses more accurately while still accounting for the requirements set by the ultimate- and serviceability limit states. By using SynFRC in combination with the Yield-Line theory as design method, thinner floor slabs can be obtained than with the Westegaard theory. AFRIKAANSE OPSOMMING: Beton word gebruik as boumateriaal in meeste hedendaagse infrastruktuur. Daar bestaan verskeie ontwerp kodes en riglyne vir die gebruik en oprig van beton strukture. Alhoewel beton sterk in kompressie is, het beton ‘n swak treksterkte in beide die vars- en harde fases en faal dit in ‘n bros manier indien onbewapen. Die gebruik van sintetiese vesels in beton word in hierdie projek ondersoek om die invloed daarvan op die eienskappe van die meganiesegedrag van beton te bepaal. Grond geondersteunde vloere word as toepassing gebruik. Parallel met die materiaalgedrag wat ondersoek word, word twee ontwerpsteorieë ook ondersoek. Dit is die teorie van Westegaard en die Swig-Lyn teorie. Die teorie van Westegaard gebruik elastiese teorie in ontwerpsberekeninge terwyl die Swig-Lyn teorie ‘n plastiese analise gebruik. ‘n Konseptuele vloerontwerp is gedoen deur beide die ontwerpsmetodes te gebruik. Materiaalparameters is bepaal deur buig-toetse uit te voer op sintetiesevesel-bewapende beton. Grootskaalse betonblaaie is gegiet en getoets om die akkuraatheid van die twee metodes te verifieer. Die betonblaaie wat bewapen was met polipropileen vesels het groter laste gedra tot by faling as die blaaie wat nie bewapen was nie. Die vesels verbeter die gedrag van beton in die plastiese gebied van materiaalgedrag deurdat laste ondersteun word nadat die beton alreeds gekraak het. Die Westegaard teorie kan as konserwatief beskou word deurdat dit vloerdiktes oorskat. Hierdie stelling is gegrond op eksperimentele data wat bewys dat onbewapende betonblaaie groter laste kan dra as wat voorspel word deur die Westegaard teorie. Die Swig-Lyn teorie voorspel ontwerpsdiktes meer akkuraat terwyl daar steeds aan die vereistes van swigting en diensbaarheid voldoen word. Deur gebruik te maak van sintetiese vesels en die Swig-Lyn teorie kan dunner betonblaaie ontwerp word as met die Westegaard teorie. 2013-11-27T13:43:56Z 2013-12-13T17:39:42Z 2013-11-27T13:43:56Z 2013-12-13T17:39:42Z 2013-12 Thesis http://hdl.handle.net/10019.1/85877 en_ZA Stellenbosch University xiii, 103 p. : ill. application/pdf Stellenbosch : Stellenbosch University
spellingShingle Textile fibres, synthetic
Concrete slabs -- Testing
Reinforced concrete construction
Yield-line analysis
Plasticity
Dissertations -- Civil engineering
Concrete slabs -- Design and construction
Theses -- Civil engineering
Bothma, Jacques
The structural use of synthetic fibres : thickness design of concrete slabs on grade
title The structural use of synthetic fibres : thickness design of concrete slabs on grade
title_full The structural use of synthetic fibres : thickness design of concrete slabs on grade
title_fullStr The structural use of synthetic fibres : thickness design of concrete slabs on grade
title_full_unstemmed The structural use of synthetic fibres : thickness design of concrete slabs on grade
title_short The structural use of synthetic fibres : thickness design of concrete slabs on grade
title_sort structural use of synthetic fibres thickness design of concrete slabs on grade
topic Textile fibres, synthetic
Concrete slabs -- Testing
Reinforced concrete construction
Yield-line analysis
Plasticity
Dissertations -- Civil engineering
Concrete slabs -- Design and construction
Theses -- Civil engineering
url http://hdl.handle.net/10019.1/85877
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