The influence of mix design parameters and compressive strenght on durability indices
| dc.contributor.advisor | Beushausen, Hans-Dieter | en_ZA |
| dc.contributor.advisor | Alexander, Mark Gavin | en_ZA |
| dc.contributor.author | Angelucci, Matteo | en_ZA |
| dc.date.accessioned | 2014-12-25T15:44:38Z | |
| dc.date.available | 2014-12-25T15:44:38Z | |
| dc.date.issued | 2013 | en_ZA |
| dc.description | Includes abstract. | en_ZA |
| dc.description.abstract | Current concrete specifications used in mix design are mainly of the prescriptive type, i.e.recipe-based specifications that prescribe limiting values for certain mix design parameters such as minimum binder content, maximum water/binder (w/b) ratio and minimum compressive strength class. This has numerous economical, technical and environmental disadvantages and is one of the driving factors behind the development and promotion of performance-based specifications. These have the potential to lead to alternative methods of mix design to improve concrete structural performance. In South Africa, the use of the Durability Index Approach in performance-based specifications has grown increasingly. Durability can be thought of as a materials concept for a structure in a given environment for the duration of its design life. As such, it can only be accurately described by considering it as a function of numerous intrinsic and extrinsic interrelated factors. Despite this, a dominant assumption in the industry is that concrete durability is directly proportional to its binder content and compressive strength, largely due to the misinterpretation of prescriptive specifications in depicting factors like binder content as the governing parameter of durability. This results in uneconomical and often non-durable concretes due to implications of high cement contents, such as high costs (cement is the most expensive constituent of concrete), high shrinkage, thermal effects and alkali-silica reactions. This thesis presents a study on the influence of parameters of mix design, such as w/b ratio, binder content, binder type and curing regime, as well as compressive strength, on the durability of concrete as expressed by the Durability Index Approach. The objective of the investigation was to identify the issues behind specifications of minimum binder contents, as well as identify relationships between mix design parameters, compressive strength and durability indices. This was done by obtaining findings which would serve as a basis to potentially bring about sensible and justifiable changes to specifications. This could in turn lead to more durability-oriented mix design strategies. In order to verify whether prescriptive specifications such as minimum binder contents are justifiable, various studies in literature were reviewed on the subject. In the literature review, it was identified that certain relationships exist between aspects of concrete durability and various parameters, among which are binder content, w/b ratio and compressive strength. It was found that the nature of these relationships cannot be generalised as each relationship needs to take into consideration a variety of additional influencing factors. One example is that the influence of increasing binder content on durability indicators is often detrimental and can seldom be associated with beneficial effects. This is because there are other factors such as increasing paste volume that need to be considered. | en_ZA |
| dc.identifier.apacitation | Angelucci, M. (2013). <i>The influence of mix design parameters and compressive strenght on durability indices</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Civil Engineering. Retrieved from http://hdl.handle.net/11427/9990 | en_ZA |
| dc.identifier.chicagocitation | Angelucci, Matteo. <i>"The influence of mix design parameters and compressive strenght on durability indices."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Civil Engineering, 2013. http://hdl.handle.net/11427/9990 | en_ZA |
| dc.identifier.citation | Angelucci, M. 2013. The influence of mix design parameters and compressive strenght on durability indices. University of Cape Town. | en_ZA |
| dc.identifier.ris | TY - Thesis / Dissertation AU - Angelucci, Matteo AB - Current concrete specifications used in mix design are mainly of the prescriptive type, i.e.recipe-based specifications that prescribe limiting values for certain mix design parameters such as minimum binder content, maximum water/binder (w/b) ratio and minimum compressive strength class. This has numerous economical, technical and environmental disadvantages and is one of the driving factors behind the development and promotion of performance-based specifications. These have the potential to lead to alternative methods of mix design to improve concrete structural performance. In South Africa, the use of the Durability Index Approach in performance-based specifications has grown increasingly. Durability can be thought of as a materials concept for a structure in a given environment for the duration of its design life. As such, it can only be accurately described by considering it as a function of numerous intrinsic and extrinsic interrelated factors. Despite this, a dominant assumption in the industry is that concrete durability is directly proportional to its binder content and compressive strength, largely due to the misinterpretation of prescriptive specifications in depicting factors like binder content as the governing parameter of durability. This results in uneconomical and often non-durable concretes due to implications of high cement contents, such as high costs (cement is the most expensive constituent of concrete), high shrinkage, thermal effects and alkali-silica reactions. This thesis presents a study on the influence of parameters of mix design, such as w/b ratio, binder content, binder type and curing regime, as well as compressive strength, on the durability of concrete as expressed by the Durability Index Approach. The objective of the investigation was to identify the issues behind specifications of minimum binder contents, as well as identify relationships between mix design parameters, compressive strength and durability indices. This was done by obtaining findings which would serve as a basis to potentially bring about sensible and justifiable changes to specifications. This could in turn lead to more durability-oriented mix design strategies. In order to verify whether prescriptive specifications such as minimum binder contents are justifiable, various studies in literature were reviewed on the subject. In the literature review, it was identified that certain relationships exist between aspects of concrete durability and various parameters, among which are binder content, w/b ratio and compressive strength. It was found that the nature of these relationships cannot be generalised as each relationship needs to take into consideration a variety of additional influencing factors. One example is that the influence of increasing binder content on durability indicators is often detrimental and can seldom be associated with beneficial effects. This is because there are other factors such as increasing paste volume that need to be considered. DA - 2013 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2013 T1 - The influence of mix design parameters and compressive strenght on durability indices TI - The influence of mix design parameters and compressive strenght on durability indices UR - http://hdl.handle.net/11427/9990 ER - | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/11427/9990 | |
| dc.identifier.vancouvercitation | Angelucci M. The influence of mix design parameters and compressive strenght on durability indices. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Civil Engineering, 2013 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/9990 | en_ZA |
| dc.language.iso | eng | en_ZA |
| dc.publisher.department | Department of Civil Engineering | en_ZA |
| dc.publisher.faculty | Faculty of Engineering and the Built Environment | |
| dc.publisher.institution | University of Cape Town | |
| dc.subject.other | Engineering | en_ZA |
| dc.title | The influence of mix design parameters and compressive strenght on durability indices | en_ZA |
| dc.type | Master Thesis | |
| dc.type.qualificationlevel | Masters | |
| dc.type.qualificationname | MSc | en_ZA |
| uct.type.filetype | Text | |
| uct.type.filetype | Image | |
| uct.type.publication | Research | en_ZA |
| uct.type.resource | Thesis | en_ZA |
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