Bamidele I O Dahunsi
University of Ibadan, Civil Engineering, Faculty Member
- I am a Professor of Civil Engineering specialising in Structural and Materials Engineeringedit
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This study was designed to investigate the Performance of melted Expanded Polystrene (EPS) wastes on the quality of bitumen used in asphaltic concrete. The EPS materials were ground and then melted (200-400 oC) to form a slurry. Specific... more
This study was designed to investigate the Performance of melted Expanded Polystrene (EPS) wastes on the quality of bitumen used in asphaltic concrete. The EPS materials were ground and then melted (200-400 oC) to form a slurry. Specific gravity of the EPS and chemical composition were determined by AAS analyses. The melted EPS was used as a modifier in mix proportions of 0, 2.5, 5, 7.5 and 10% by weight of bitumen. The 5% unmodified bitumen content obtained from the Marshall mix design was used to prepare asphalt concrete samples with 0 to 10% contents of melted EPS. The products were tested for Marshall stability, specific gravity, penetration, softening point, ductility, loss on heating, viscosity, flash and fire points and the melting point tests using standard methods. The ground EPS was uniform and well-graded (4.750-0.010 mm) with a specific gravity of 0.012, having a styrene structure with methanol on the ring. The specimen prepared with the specified mix proportion of EPS p...
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This paper discusses the perception of gravel suppliers in the six states situated in South-western Nigeria. It reported findings from a research on gravel supply studies in the study area. Major gravel pits, together with their perceived... more
This paper discusses the perception of gravel suppliers in the six states situated in South-western Nigeria. It reported findings from a research on gravel supply studies in the study area. Major gravel pits, together with their perceived technical characteristics in the states were identified through a structured questionnaire designed to solicit response from truck drivers and association of gravel suppliers. Based on this, factors affecting gravel supply and usage were measured by random variables devised for the purpose. The observed outcomes of the variables from the survey carried out constituted the research data. The collated data was analyzed based on quantitative method through the use of simple percentage method of data analysis. The paper posits that geological location of Lagos state is responsible for the absence of any gravel pit in the state, hence the prohibitive cost of gravel in the state when compared to other states in the zone. In all the states, more than 99% ...
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Pervious concrete is a low-cost and effective drainage technique for metropolitan areas that reduces storm water flow. The goal of this research is to examine the properties of gravel as a coarse aggregate material in pervious concrete.... more
Pervious concrete is a low-cost and effective drainage technique for metropolitan areas that reduces storm water flow. The goal of this research is to examine the properties of gravel as a coarse aggregate material in pervious concrete. The geotechnical properties of the gravel were investigated to determine their suitability in the construction of pervious drainage structures. The samples collected were subjected to particle size distribution test, aggregate crushing value test, and aggregate impact value test. The concrete samples were then put through a series of tests, including a slump test, a compressive strength test, a density test, and a permeability test. In accordance with the particle size distribution result, the gravel is properly graded. The slump test affirms that as the aggregate size of the pervious concrete reduces, the workability improves. Coarse aggregate of 13.2mm size, had highest compressive strength (4.889KN/) at 28days while those of 19.00mm, 25.00mm, and ...
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The rate at which timber chars varies between species and predominately dependent on density and moisture content. This study involved determination of charring performance of Nigerian wood species used for constructional purposes and... more
The rate at which timber chars varies between species and predominately dependent on density and moisture content. This study involved determination of charring performance of Nigerian wood species used for constructional purposes and comparing their charring rate with selected existing models. Six out of ten identified wood species commonly used for constructional purposes: Terminalia superba (Black Afara), Milicia excels (Iroko), Nauclea diderrichii (Opepe), Khaya ivorensis (Mahogany), Mansonia altissima (Mansonia), Tectona grandis (Teak) were selected for the study. The densities of the woods were determined at Moisture Contents (MC) of 9.0, 12.0, and 15.0%. Selected samples from each species, were exposed to fire at temperature ranges of 20° to 230°C for 30 min; 230° to 300°C for 30 min; 20° to 300°C for 60 min. The charring rate results based on 15% moisture content for all 0 - 30 min, 30 - 60 min and 0 - 60 min, being the ones having the lowest correlation values at each...
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The research investigated changes in post fire density and strength properties of Nigerian wood species used for construction. The selected species are: Terminalia superba (Afara), Milicia excels (Iroko), Nauclea diderrichii (Opepe),... more
The research investigated changes in post fire density and strength properties of Nigerian wood species used for construction. The selected species are: Terminalia superba (Afara), Milicia excels (Iroko), Nauclea diderrichii (Opepe), Khaya ivorensis (Mahogany), Mansonia altissima (Mansonia), Tectona grandis (Teak). Densities and strength properties of the species were determined at Moisture Contents (MC) of 9.0, 12.0, and 15.0%. Species were exposed to fire at various temperature ranges. The results revealed that at 9, 12 and 15%MC, Opepe had the highest density values of 630±28.85kg/m³, 686±22.64kg/m³ and 752±17.22 kg/m³ respectively. At 9%MC, Mahogany had the lowest density (439±10.58kg/m³) while at 12 and 15%MC, Afara had the lowest density values of 444±4.18kg/m³ and 469±7.07kg/m³ respectively. Post fire exposure revealed that Afara had the highest percentage loss in density 29.2% and strength properties, while both Iroko and Mahogany exhibited the lowest percentage loss in both...
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As part of effort to understand challenges faced with building maintenance practices in Nigeria an investigation of the maintenance culture in some of the oldest public schools in Ibadan, Oyo State Nigeria was carried out. A total of five... more
As part of effort to understand challenges faced with building maintenance practices in Nigeria an investigation of the maintenance culture in some of the oldest public schools in Ibadan, Oyo State Nigeria was carried out. A total of five schools located within Ibadan metropolis were selected based on their historical importance, year of establishment and viability of alumni. Site visits were carried out, during these visits, oral interviews accompanied with questionnaires was administered on the stake holders, the buildings were visually assessed to determine severity of degradation experienced by the buildings and the risk it poses to learning. Photographs of structures been assessed were also taken. Results shows that, the buildings have not been properly maintained over the years and can be attributed to the following: lack of funding for maintenance works, absence of guidelines for maintenance of school buildings by Government, lack of maintenance department in the schools visi...
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The use of bio-oils in the production of asphalt binders has found application mostly in cold climates, and not in hot climates due to the rutting problems associated with bio-oil modified binders. The reality of a harsh and changing... more
The use of bio-oils in the production of asphalt binders has found application mostly in cold climates, and not in hot climates due to the rutting problems associated with bio-oil modified binders. The reality of a harsh and changing climate faced by today’s world necessitates an enhancement of the temperature susceptibility of these binders. This is the focus of this research. In this research, high-density polyethylene (HDPE) is combined with waste cooking oil (WCO) to develop an asphalt binder with improved properties. The results obtained showed that when 7.5% HDPE was added to the binder with 15% replacement of the base bitumen with WCO (B85-WCO15), a 54.7% increase in softening point and 9.3% decrease in penetration were obtained. It was found that higher percentages of WCO can be used for bitumen modification if HDPE is used as a stabilizer. The increased specific gravity obtained from the addition of HDPE provides further evidence that HDPE can be used to stabilize WCO modified binder. The penetration index values indicate that HDPE can be used to reduce the temperature susceptibility of the bio-oil modified binder. The results obtained from this research suggest that waste oils and waste HDPE can be blended in asphalt mixes to deliver asphalt pavements with improved performance.
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Abstract The huge amount incurred in the construction of rigid pavement necessitates the use of cheaper alternative materials. This experimental research assessed the rheology, strength and microstructure of de-hydroxylated Kaolinitic... more
Abstract The huge amount incurred in the construction of rigid pavement necessitates the use of cheaper alternative materials. This experimental research assessed the rheology, strength and microstructure of de-hydroxylated Kaolinitic clay in self-compacting concrete for pavement construction using a special brand of Portland limestone cement (Technical Cement). The huge demand for the use of supplementary cementitious material in concrete technology and the variation in the physical and chemical composition of these materials require the need for the design of their use in concrete work. The Kaolinitic clay was de-hydroxylated at 750 °C. This was used as a partial replacement for cement at 0%, 5%, 10%, 15%, 20% and 25%. Six (6) concrete samples were developed varying the cement brand. Both strength and workability properties of the developed self-compacting concrete were assessed. Slump flow, L-box test and V-funnel test were carried out alongside the compressive, split tensile and flexural strength test. Response surface analysis was carried out to know the relationship between the mechanical properties of the concrete. Additionally, the microstructure of the concrete at maturity was also assessed. The result of the research revealed that at 15% addition of metakaolin the slump flow, passing ability and filling ability did not satisfy the EFNARC standard for self-compacting concrete. From the numerical optimization of the flexural strength, the maximum predicted flexural strength of 4.86 MPa was obtained. The response surface also revealed that at lower values of metakaolin, the compressive strength increased as the age of the concrete increased from 3 to 150 days. The age with the optimum concrete strength formation was 110 days with the metakaolin addition of 52.73 kg based on the optimization analysis. In a bid to encourage the use of sustainable supplementary materials in rigid pavement construction, the choice of de-hydroxylated Kaolinitic clay is a viable option.
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Abstract This paper investigates strength properties of some selected cement brands for self-compacting concrete application in pavement construction. Three brands each of Portland limestone cement grades, CEM II/A-L 42.5 (Brand A), CEM... more
Abstract This paper investigates strength properties of some selected cement brands for self-compacting concrete application in pavement construction. Three brands each of Portland limestone cement grades, CEM II/A-L 42.5 (Brand A), CEM II/B-L 32.5 (Brand B) and CEM II/B-L 32.5 (Brand C), were used. Rheological test was carried out using the L-Box, V-Funnel and slump cone while compressive and flexural strength tests were carried out, on the hardened concrete, at 3, 7, 14, 21 and 28 days. Brand A exhibited the highest compressive strength right from 3rd day test and maintained this performance through maturity (the 28th day test). Also Brand A had the highest flexural strength of 4.54 MPa, as against 4.5 MPa specified for road construction, at 28 days, while Brand B and Brand C exhibited strengths that were lower. Although Brand C showed good rheological properties, it exhibited the lowest strength properties among the cement grades. These findings engender implication that cement grade lower than 42.5 should be discouraged in pavement construction.
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The performance of Nigeria timber species under fire exposure to prevent collapse of structure has not been adequately investigated. This study was to determine the charring rate models of some selected timber species mostly used for... more
The performance of Nigeria timber species under fire exposure to prevent collapse of structure has not been adequately investigated. This study was to determine the charring rate models of some selected timber species mostly used for constructional purposes in Southwestern Nigeria. Six species out of ten identified timbers were selected for studies. They are: Afara, Iroko, Opepe, Mahogany, Mansonia, and Teak. The densities of the timber species were determined at Moisture Contents (MC) of 9.0, 12.0, and 15.0%. Samples from each of the selected species, were exposed to fire at temperature ranges of 20° to 230° C for 30 minutes; 20° to 300° C for 60 minutes; 230° to 600° C for 30 minutes. Empirical statistical model was developed for charring rate of the timber species. The models were analysed using ANOVA at . At 30 minutes fire exposure (20 to 230° C), Afara of 9.0, 12.0 and 15.0% MC had the highest mean charring rates of 0.84±0.02mm/min, 0.82±0.02mm/min and 0.82±0.02mm/min respecti...
This study aimed to evaluate the percentage variations of density and compressive strength of some selected timber species mostly used for constructional purposes in Southwestern Nigeria after undergoing fire exposure. The species are:... more
This study aimed to evaluate the percentage variations of density and compressive strength of some selected timber species mostly used for constructional purposes in Southwestern Nigeria after undergoing fire exposure. The species are: Terminalia superba (Afara), Milicia excelsa (Iroko), Nauclea diderrichii (Opepe), Khaya ivorensis (Mahogany), Mansonia altissima (Mansonia), Tectona grandis (Teak).The densities and the compressive strengths of the species were determined at Moisture Contents (MC) of 9.0, 12.0, and 15.0%. Nine specimen per species, were exposed to fire at various temperature ranges.The results of analysis by variance revealed that at 9% MC, Mahogany had the lowest density value of 439±10.58Kg/m³. At 12 and 15% MC, Afara had the lowest density values of 444±4.18Kg/m³ and 469±7.07Kg/m³ respectively. At 9, 12 and 15% MC, Opepe had the highest density values of 630±28.85Kg/m³, 686±22.64Kg/m³ and 752±17.22Kg/m³ respectively. Afara of 9, 12 and 15% MC had the lowest compres...
The gradually exhausting crude oil reserves worldwide have made experts in the building industry to explore alternative resources for road construction materials. This study was designed to evaluate the potential applications of engine... more
The gradually exhausting crude oil reserves worldwide have made experts in the building industry to explore alternative resources for road construction materials. This study was designed to evaluate the potential applications of engine oil wastes as a bitumen modifier. The Waste Engine Oil (WEO) was obtained from an auto mechanic workshop. The base bitumen was replaced with WEO at 2, 4, 6, 8 and 10% respectively. The WEO modified bitumen properties which included penetration, softening point, flash point, solubility, specific gravity and viscosity were measured in accordance to ASTM standard procedures for a period of 5 days. From the results obtained it was observed that as the replacement level of the WEO increased, there was decrease in the viscosity, specific gravity, flash point and the softening point properties. Incorporating WEO into the base bitumen can at best be acceptable at 2% - 4%.
Field trips were undertaken as a preliminary exercise, to identify the available rattan species in Western Nigeria and to estimate the quantities available. Information relating to their end-uses was collected from cane furniture makers... more
Field trips were undertaken as a preliminary exercise, to identify the available rattan species in Western Nigeria and to estimate the quantities available. Information relating to their end-uses was collected from cane furniture makers and other rattan cane users through the use of questionnaires and personal observation. The species in descending order of availability were Calamus deeratus, Eremospatha macrocarpa, Oncocalamus
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Field trips were undertaken as a preliminary exercise, to identify the available rattan species in Western Nigeria and to estimate the quantities available. Information relating to their end-uses was collected from cane furniture makers... more
Field trips were undertaken as a preliminary exercise, to identify the available rattan species in Western Nigeria and to estimate the quantities available. Information relating to their end-uses was collected from cane furniture makers and other rattan cane users through the use of questionnaires and personal observation. The species in descending order of availability were Calamus deeratus, Eremospatha macrocarpa, Oncocalamus manni and Laccosperma secondiflorum. L. secundiflorum, C. deerratus, E. macrocarpa and O. manni having average stock densities per plot of 100 square metres of 6, 22, 12 and 18 clumps respectively. The diameters of the small-stemmed rattan species (C. deerratus, E. macrocarpa and O. manni) ranged from 7.2 to 17.8mm while that of L. secundiflorum, a large stemmed species, ranged from 12.5 to 38.5mm. Rattan canes were mainly from wild stocks and cane furniture/handicraft weavers form the bulk of cane users. Other uses of cane within the study area include: as c...
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ABSTRACT The suitability of the shells from periwinkle, a small gastropod sea snail (mollusc), for use as partial replacement of granite in concrete was investigated. Physical and mechanical properties of the shells and well-graded... more
ABSTRACT The suitability of the shells from periwinkle, a small gastropod sea snail (mollusc), for use as partial replacement of granite in concrete was investigated. Physical and mechanical properties of the shells and well-graded granite chippings were determined and compared. Concrete cubes were prepared using 1:0, 1:1, 1:3, 3:1 and 0:1 proportions of periwinkle shells and granite chippings by weight, as coarse aggregate. Compressive strength tests were carried out on the periwinkle-granite concrete cubes. The bulk density of the periwinkle shells was found to be 1353kg/m3 while that for granite was 2644kg/m3. The ten percent fines and aggregate crushing values were 26KN and 64% respectively for periwinkle shells while for granite they were 114KN and 18%. Concrete cubes with periwinkle shells alone as coarse aggregate were lighter and of lower compressive strengths compared to those with other periwinkle:granite proportions. The 28-days density and compressive strength were 1824kg/m3 and 12.12N/mm2 respectively. Density, workability and the compressive strength of periwinkle concrete increased with increasing inclusion of granite chippings. It could be concluded from this study that periwinkle shells could be used as partial replacement for granite in normal construction works especially in places where granite is in short supply and periwinkle shells are readily available.
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Field trips were undertaken as a preliminary exercise, to identify the available rattan species in Western Nigeria and to estimate the quantities available. Information relating to their end-uses was collected from cane furniture makers... more
Field trips were undertaken as a preliminary exercise, to identify the available rattan species in Western Nigeria and to estimate the quantities available. Information relating to their end-uses was collected from cane furniture makers and other rattan cane users through the use of questionnaires and personal observation. The species in descending order of availability were Calamus deeratus, Eremospatha macrocarpa, Oncocalamus manni and Laccosperma secondiflorum. L. secundiflorum, C. deerratus, E. macrocarpa and O. manni having average stock densities per plot oflOO square metres of6, 22, 12 and 18 clumps respectively. The diameters of the small-stemmed rattan species (C. deerratus, E. macrocarpa and O. manni) ranged from 7.2 to 17.8mm while that of L. secundiflorum, a large stemmed species, ranged from 12.5 to 38.5mm. Rattan canes were mainly from wild stocks and cane furniture/handicraft weavers form the bulk of cane users. Other uses of cane within the study area include: as cane for flogging, ropes for tying hides to drum frames, fish traps and loop for climbing palm trees. The wastage from harvesting operation of the rattan canes ranged from 20 to 55 percent of the length of the plant.Rattan plants if properly harnessed, and their biological, physical and mechanical properties understood, could contribute significantly to the economy of African nations.
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... 17. JP Profi zi, Notes on West African rattans, RIC Bulletin 5 (1), 13 (1986). 18. D.Komolafe, Cane makers face raw material scarcity, Daily Times (Nigeria) (5 August), 30 (1992). Page 12. 56 EB Lucas and BIO Dahunsi 19. Association... more
... 17. JP Profi zi, Notes on West African rattans, RIC Bulletin 5 (1), 13 (1986). 18. D.Komolafe, Cane makers face raw material scarcity, Daily Times (Nigeria) (5 August), 30 (1992). Page 12. 56 EB Lucas and BIO Dahunsi 19. Association ...