Showing items 1 - 7 of 7

Your selections:

Characterization of rice hull ash and its performance in turbidity removal from water

- Adams, F. V., Ikotun, B. D., Patrick, D. O., Mulaba-Bafubiandi, A. F.

  • Authors: Adams, F. V. , Ikotun, B. D. , Patrick, D. O. , Mulaba-Bafubiandi, A. F.
  • Date: 2014
  • Subjects: Rice hull ash , Turbidity removal
  • Type: Article
  • Identifier: uj:4790 , http://hdl.handle.net/10210/12041
  • Description: This study characterizes the locally obtained samples of rice hull ash and investigates its performance on turbidity removal from water. Four samples of this material were studied, namely, unwashed parboiled rice hull ash (UPRHA), washed parboiled rice hull ash (WPRHA), unwashed unparboiled rice hull ash (UUPRHA), and washed unparboiled rice hull ash (WUPRHA). Scanning electron microscopy (SEM), x-ray diffractometer (XRD), and Fourier infrared spectroscopy (FTIR) were carried out to characterize these samples. A filtration process was carried out to investigate the effectiveness of the rice hull ash medium in removing water turbidity. The XRD results showed the silica, which is present in the ashes, to be cristobalite, quartz, and tridymite. The silica contents of the UUPRHA and WUPRHA were observed to be 77.10% and 98.24%, respectively, while those of UPRHA and WPRHA were 79.07% and 94.97%, respectively. The SEM images showed agglomeration of ash particles after the ashes were washed. The washed RHA samples showed improved pH, a good percentage of turbidity removal (<5 NTU) from water sample. Washing RHA with distilled water increased the efficiency of RHA in turbidity removal from water and regulated water pH to an acceptable range.
  • Full Text: false

Durability index of dry sludge incorporated concrete when used as sand replacement

- Ikotun, B. D., Mathye, R. P., Fanourakis, George C.

  • Authors: Ikotun, B. D. , Mathye, R. P. , Fanourakis, George C.
  • Date: 2019
  • Subjects: Dry sludge , Oxygen Permeability Index , Chloride Conductivity Index
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/396782 , uj:32952 , Citation: Ikotun, B.D., Mathye, R.P. & Fanourakis, G. C. 2019. Durability index of dry sludge incorporated concrete when used as sand replacement.
  • Description: Abstract: It is paramount to look for alternative ways of disposing dry sludge, as present disposal methods are environmentally unsustainable. Hence, the investigation on the possible inclusion of dry sludge in concrete. More specifically, this paper presents and discusses the effect of dry sludge used as a partial sand replacement on concrete durability indexes. Two durability indexes were assessed in this article, which are Oxygen permeability index (OPI) and chloride conductivity index (CCI). The OPI gives an indication of concrete’s resistance to the flow of water through continuous pores, at a given pressure and temperature, while the CCI provides an indication of concrete’s resistance to chloride infiltration. Dry sludge was used as a sand replacement, in the proportion of 0 %, 1 %, 3 % and 5 %. The 0 % sample served as the control sample. Three water cement ratios (W/C), of 0.67, 0.69 and 0.80, were assessed. The samples were water cured for 28 and 90 days before testing. The results showed that higher W/C and higher sludge replacement had a detrimental effect on concrete OPI. In addition, the CCI results show that dry sludge had a positive ionic reaction and good sulphuric attack resistance on concrete.
  • Full Text:

Modification of the hydration products of hydrated cement paste by fly ash, β-cyclodextrin and fly ash-β-cyclodextrin composite

- Ikotun, B. D., Mishra S., Fanourakis, George C.

Structural Characterisation of four South African fly ashes and their structural changes with β-cyclodextrin

- Ikotun, B. D., Mishra, S., Fanourakis, George C.

The effect of dry wastewater sludge as sand replacement on concrete strengths

- Mathye, R. P., Ikotun, B. D., Fanourakis, George C.

  • Authors: Mathye, R. P. , Ikotun, B. D. , Fanourakis, George C.
  • Date: 2020
  • Subjects: Dry wastewater sludge , Concrete , Compressive Strength
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/460467 , uj:40977 , Citation: Mathye, R.P., Ikotun, B.D. & Fanourakis, G.C. 2020. The effect of dry wastewater sludge as sand replacement on concrete strengths.
  • Description: Abstract: The ever-increasing population continues to have the ripple effect on the increase in sludge production. Dry sludge generally is heaped up on a landfill, which causes environmental pollution. Therefore, the study on the alternative use of dry sludge is of paramount importance. The dry wastewater sludge obtained from the Northwest treatment plant (NWTP) in Johannesburg, South Africa was used in this study as partial replacement of sand in concrete. Concrete were produced with 0%, 1%, 3% and 5% sand replacement with dry wastewater sludge. Compressive strength and splitting tensile strength tests were performed to study the effect of the dry sludge on concrete strengths. Samples for compressive strength test were prepared with fixed Water-cement (W/C) ratios of 0.67, 0.69 and 0.8 and cured for 3, 7, 28 and 90 days. However, samples for splitting tensile strength test were prepared with fixed Water-cement (W/ C) ratios of 0.67 and 0.69 and cured for 28 and 90 days. The results showed a notable reduction of concrete strengths with an increase in sludge replacement. The compressive strength of 1% replacement at a W/C of 0.67 after 90 days curing recorded 16% reduction compared to the control sample, while 13% reduction was recorded for splitting tensile strength. The 90 days strength results showed that the sludge could be utilized (for non-structural purposes) as a partial sand replacement of concrete mixtures at aW/ C of 0.67 with optimum percentage lower than 3%.
  • Full Text:

The effect of dry wastewater sludge as sand replacement on concrete strengths

- Mathye, R. P., Ikotun, B. D., Fanourakis, G. C.

The effect of fly ash, β-cyclodextrin and fly ash-β-cyclodextrin composites on concrete workability and strength

- Ikotun, B. D., Fanourakis, George C., Mishra, Bhardwaj S.

  • Authors: Ikotun, B. D. , Fanourakis, George C. , Mishra, Bhardwaj S.
  • Date: 2017
  • Subjects: Composite , Compressive strength , Cyclodextrin
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/241655 , uj:24908 , Citation: Ikotun, B.D., Fanourakis, G.C. & Mishra, B.S. 2017. The effect of fly ash, β-cyclodextrin and fly ash-β-cyclodextrin composites on concrete workability and strength.
  • Description: Abstract: To increase the use of fly ash (FA) as a pozzolanic material in concrete, a composite was formed with an interaction of FA with β-cyclodextrin (β-CD). Further research was carried out in this article to study the effects of replacing cement with FA (30% and 50% by mass), β-CD (0.025%, 0.05% and 0.1%) and FA-β-CD composite on the workability and strength of concrete. Workability was assessed by means of the slump test and strengths were assessed using the compressive and split tensile strength tests. Higher combined contents of FA and β- CD resulted in increased workability of concrete of up to approximately 550 %. Furthermore, the inclusion of β-CD generally increased both the compressive and tensile strengths of the concretes not containing FA by up to 10 %. When combined with FA, the β-CD resulted in increased compressive strengths of up to 63 % and tensile strengths of up to 28 %, compared to the relevant pozzolanic concretes which did not include β-CD. The study contributed to the knowledge of FA performance using cyclodextrin and promoted the continued inclusion of FA in concrete, which in turn should reduce the environmental pollution resulting from FA.
  • Full Text:
  • 1
  • Disclaimer
  • Privacy
  • Copyright
  • Contact