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Browsing Faculty of Engineering by Author "Abiodun, Y.O."
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- ItemRestrictedMicrostructural characterisation, physical and chemical properties of Rice husk ash as viable pozzolan in building material: A case study of some Nigerian grown rice varieties(Nigerian Journal of Technology (NIJOTECH), 2018) Abiodun, Y.O.; Jimoh, A.A.Recycling of agricultural wastes such as rice husk ash as pozzolan is being increasingly encouraged, particularly in developing countries. In this paper, preliminary investigation on the physical and chemical compositions of rice husk ash using different techniques was carried out. Scanning Electron Microscopy (SEM) images of the rice husk ash showed residual pores to be distributed within the ash sample, indicating that the silica is a highly porous material with a large internal surface area. Samples burnt at 400 degree Celcius for 6 hours and 600 degree Celcius for 4 hours for ‘Bukus’ and ‘Soro/ Olomo nla’ show aggregates with clearly defined layers of loose flakes compared to ‘Faro 58’. The Energy dispersive xray spectroscopy (EDX) analysis of rice husk ash performed to determine percentages of silica present in the samples were graphically represented. Nine elements (Al, Si, K, Ca, Br, Fe, Mg, Na, Mn) and their corresponding oxides (Al2O3, SiO2, K2O, CaO, Br, Fe2O3, MgO, Na2O, MnO) were detected with varying concentrations. The three varieties, on the average possess good silica content of over 50% considering the two varied temperature and time. Therefore, the chemical analysis results show that burning at combustion temperature of 600 degree Celcius for 4hrs, gives optimal result than at 400 degree Celcius for 6hrs because all the samples show high Silica content (Faro 58; 61.9, Bukus; 62.6 and Soro/Olomo nla; 59.5).
- ItemOpen AccessMicrostructural characterisation, physical and chemical properties of Rice husk ash as viable pozzolan in building material: A case study of some Nigerian grown rice varieties(Nigerian Journal of Technology, 2018) Abiodun, Y.O.; Jimoh, A.A.Recycling of agricultural wastes such as rice husk ash as pozzolan is being increasingly encouraged, particularly in developing countries. In this paper, preliminary investigation on the physical and chemical compositions of rice husk ash using different techniques was carried out. Scanning Electron Microscopy (SEM) images of the rice husk ash showed residual pores to be distributed within the ash sample, indicating that the silica is a highly porous material with a large internal surface area. Samples burnt at 4000C for 6 hours and 6000C for 4 hours for ‘Bukus’ and ‘Soro/ Olomo nla’ show aggregates with clearly defined layers of loose flakes compared to ‘Faro 58’. The Energy dispersive xray spectroscopy (EDX) analysis of rice husk ash performed to determine percentages of silica present in the samples were graphically represented. Nine elements (Al, Si, K, Ca, Br, Fe, Mg, Na, Mn) and their corresponding oxides (Al2O3, SiO2, K2O, CaO, Br, Fe2O3, MgO, Na2O, MnO) were detected with varying concentrations. The three varieties, on the average possess good silica content of over 50% considering the two varied temperature and time. Therefore, the chemical analysis results show that burning at combustion temperature of 6000C for 4hrs, gives optimal result than at 4000C for 6hrs because all the samples show high Silica content (Faro 58; 61.9, Bukus; 62.6 and Soro/Olomo nla; 59.5).
- ItemOpen AccessMicrostructural, mechanical and pozzolanic characteristics of metakaolin-based geopolymer(Geology, Geophysics and Environment, 2020) Abiodun, Y.O.; Sadiq, O.M.; Adeosun, S.O.The use of cement contributes to global CO2 emission and this leads to the depletion of ozone layer, causing global warming. The quest to reduce or eliminate this problem has resulted in the discovery of metakaolin-based geopolymer as an alternative to the use of cement in construction work. In this study, metakaolin obtained as a result of kaolin calcination from some deposits in Nigeria; Ogun (Imeko), Edo (Okpela), Ondo (Ifon) and Ekiti (Isan-Ekiti) were characterized and used to determine the compressive and flexural strength of metakaolin-based geopolymer concrete (Mk-GPC). Cubes of 150 × 150 × 150 mm were used for the compressive strength test and reinforced concrete beams of size 150 × 250 × 2160 mm were produced to test for flexural strength. A water-absorption test was also carried out on Mk-GPC and the effect of ball-milling was assessed on the strength properties. The results from the various tests showed that 800°C for 1 hour of calcination of kaolin gives best combination of performance properties due to the presence of amorphous silica in metakaolin. Mk-GPC gave higher compressive strength and at an early age than ordinary Portland cement (OPC) concrete. The water absorption capacities of Mk-GPC were higher than the control samples. In the flexural strength test, the reinforced beams failed in flexural-shear mode and the shear capacities at 28-, 56- and 90-day curing age of the beams were between 0.656 and 0.938 MPa for Mk-GPC beams and between 0.563 and 0.844 MPa for the control beams. The moment capacities for the beams were between 19.25 and 33.25 (×10³ kgm²/s²) for Mk-GPC beams and were between 22.75 and 28.0 (×10³ kgm²/s²) for the control beams. The study has revealed that metakaolin-based geopolymer can serve as an alternative to cement for sustainable construction in the Nigerian construction industry.