Indicative tests on the effect of fly ash-β cyclodextrin composite on mortar and concrete permeability, sorptivity and porosity
- Ikotun, B.D., Fanourakis, George C., Mishra, S., Fanourakis, G.C.
- Authors: Ikotun, B.D. , Fanourakis, George C. , Mishra, S. , Fanourakis, G.C.
- Date: 2014
- Subjects: Fly ash , Composite materials , Polymer-impregnated concrete , Cyclodextrins , Concrete
- Type: Article
- Identifier: uj:5067 , http://hdl.handle.net/10210/13638
- Description: The focus of this research is to modify fly ash (FA) structure using β - cyclodextrin (β-CD) to increase its pozzolanic function in concrete. A previous study by the authors has shown that a composite is formed due to structural changes of fly ash by its interaction with cyclodextrin [1]. The objective of this paper was to assess the effect of fly ash-β cyclodextrin composite (FA-β-CD) on the transport properties (durability performance) of mortar and concrete, with a view to optimise its incorporation in concrete. The durability performance of mortar and concrete were assessed from the measurement of oxygen gas permeability, sorptivity and porosity using the South Africa durability index approach. Six mixtures were tested, comprising a control mixture (100% Portland Cement, PC), and five mixes containing the FA-β CD composite. All the composite mixes included 30 % FA by mass. The β-CD was mixed with the FA, in separate mixtures, in proportions of 0.1 %, 0.2 % and 0.5 %. Two sample preparation procedures were followed for FA-β-CD composites mixtures; firstly, physical mixtures of a pre-weighed amount of β-CD and FA were adopted for the dry mixtures and secondly, 0.0103M, 0.0206M and 0.0516Mβ-CD solutions were added to the concrete at the mixing stage for solution mixtures. The results indicated that FA-β-CD composite improved the flowability and durability performances when β-cyclodextrin (β-CD) was used at a lower percentage (0.1% and 0.2%).
- Full Text:
- Authors: Ikotun, B.D. , Fanourakis, George C. , Mishra, S. , Fanourakis, G.C.
- Date: 2014
- Subjects: Fly ash , Composite materials , Polymer-impregnated concrete , Cyclodextrins , Concrete
- Type: Article
- Identifier: uj:5067 , http://hdl.handle.net/10210/13638
- Description: The focus of this research is to modify fly ash (FA) structure using β - cyclodextrin (β-CD) to increase its pozzolanic function in concrete. A previous study by the authors has shown that a composite is formed due to structural changes of fly ash by its interaction with cyclodextrin [1]. The objective of this paper was to assess the effect of fly ash-β cyclodextrin composite (FA-β-CD) on the transport properties (durability performance) of mortar and concrete, with a view to optimise its incorporation in concrete. The durability performance of mortar and concrete were assessed from the measurement of oxygen gas permeability, sorptivity and porosity using the South Africa durability index approach. Six mixtures were tested, comprising a control mixture (100% Portland Cement, PC), and five mixes containing the FA-β CD composite. All the composite mixes included 30 % FA by mass. The β-CD was mixed with the FA, in separate mixtures, in proportions of 0.1 %, 0.2 % and 0.5 %. Two sample preparation procedures were followed for FA-β-CD composites mixtures; firstly, physical mixtures of a pre-weighed amount of β-CD and FA were adopted for the dry mixtures and secondly, 0.0103M, 0.0206M and 0.0516Mβ-CD solutions were added to the concrete at the mixing stage for solution mixtures. The results indicated that FA-β-CD composite improved the flowability and durability performances when β-cyclodextrin (β-CD) was used at a lower percentage (0.1% and 0.2%).
- Full Text:
Structural Characterisation of four South African fly ashes and their structural changes with β-cyclodextrin
- Ikotun, B. D., Mishra, S., Fanourakis, George C.
- Authors: Ikotun, B. D. , Mishra, S. , Fanourakis, George C.
- Date: 2014
- Subjects: Analysis , FA-βCD composites , Microstructural characterisation
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/460499 , uj:40981 , Citation: B. D. Ikotun, S. Mishra & G. C. Fanourakis (2014) Structural Characterization of Four South African Fly Ashes and Their Structural Changes with β-Cyclodextrin, Particulate Science and Technology, 32:4, 360-365, DOI: 10.1080/02726351.2013.879240
- Description: Abstract: This paper looks into the microstructural characteristics of some South African fly ashes and their structural changes with β-cyclodextrin so as to compare their structural responses to FA- βCD composite. Four different fly ashes, obtained from different power stations in South Africa were subjected to XRF, particle size distribution, XRD and FTIR analysis. FA-βCD composites were subjected to XRD and FTIR analyses. The XRF analysis showed that all the fly ash samples used are in class F with SiO2 + Al2O3 + Fe2O3 greater than 70 %. The average particle sizes of all the fly ash samples are less than 0.075 mm. The major mineral phase in all the fly ash samples investigated is Quartz (SiO2). The FTIR analysis shows Si-O-Si asymmetric and Al-O Symmetric stretching vibrations in all the fly ash samples. FA-βCD composites for all the fly ashes revealed additional upcoming peaks between diffraction angles (2θ) 100 and 250, which are not in their raw fly ashes...
- Full Text:
- Authors: Ikotun, B. D. , Mishra, S. , Fanourakis, George C.
- Date: 2014
- Subjects: Analysis , FA-βCD composites , Microstructural characterisation
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/460499 , uj:40981 , Citation: B. D. Ikotun, S. Mishra & G. C. Fanourakis (2014) Structural Characterization of Four South African Fly Ashes and Their Structural Changes with β-Cyclodextrin, Particulate Science and Technology, 32:4, 360-365, DOI: 10.1080/02726351.2013.879240
- Description: Abstract: This paper looks into the microstructural characteristics of some South African fly ashes and their structural changes with β-cyclodextrin so as to compare their structural responses to FA- βCD composite. Four different fly ashes, obtained from different power stations in South Africa were subjected to XRF, particle size distribution, XRD and FTIR analysis. FA-βCD composites were subjected to XRD and FTIR analyses. The XRF analysis showed that all the fly ash samples used are in class F with SiO2 + Al2O3 + Fe2O3 greater than 70 %. The average particle sizes of all the fly ash samples are less than 0.075 mm. The major mineral phase in all the fly ash samples investigated is Quartz (SiO2). The FTIR analysis shows Si-O-Si asymmetric and Al-O Symmetric stretching vibrations in all the fly ash samples. FA-βCD composites for all the fly ashes revealed additional upcoming peaks between diffraction angles (2θ) 100 and 250, which are not in their raw fly ashes...
- Full Text:
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