Civil & Environmental Engineering- Scholarly Publications

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Browsing Civil & Environmental Engineering- Scholarly Publications by Author "Adeboje, A.O."

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    Open Access
    Assessment of road accidents in Nigeria (a case study of Lagos-Ibadan Expressway)
    (Nigerian society of Engineer, 2013-06) Adeboje, A.O.; Olutaiwo, A.O.; Adedimila, A.S.
    Lagos-Ibadan Expressway is infamous for high accident rate, leading to loss of innocent lives. The contributions of human, road, vehicle and environmental factors to these road accidents were examined. A comprehensive questionnaire was distributed to one hundred (100) respondents (drivers, passengers, health workers, federal road safety officers, passengers and students of tertiary institutions, to obtain their views on accidents. Official reports on road accidents were obtained from LUTH, UCH and FRSC and subjected to statistical analyses. It was established that the human factors (nonchalant attitude of drivers, distractions from passengers and carelessness of pedestrians) among others, contribute most to accident followed by road factor, then vehicle factor while the environmental factor contributes least. Analysis also shows that at least one (1) person is killed; at least 3 people are injured out of at least 6 people involved in a single accident on the Lagos - Ibadan Expressway.
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    Open Access
    Basic oxygen furnace slag for road pavements: A review of material characteristics and performance for effective utilisation in southern Africa
    (Elsevier, 2017-05) Kambole, C.; Paige-Green, P.; Kupolati, W.K.; Ndambuki, J.M.; Adeboje, A.O.
    Basic oxygen furnace (BOF) slag aggregates exhibit several favourable technical and environmental characteristics compared with natural stone aggregates, making them potentially valuable road construction materials. BOF slag-bitumen mixes have shown better resilient moduli, rutting resistance, bonding and moisture damage resistance and stripping resistance than mixes with natural aggregates and they can also be high quality substitutes for natural aggregate in lower road pavement layers. Regrettably, most southern African specifications do not cater for slags resulting in limited BOF slag reuse hitherto. This may be due to observed pavement performance problems arising from some chemical constituents in this slag. Excessive free lime (f-CaO) and periclase (MgO) in slags react with water, resulting in large volume expansions which can lead to premature failure when used in roads. Aging treatment hydrates these oxides, thus ensuring allowable slag expansion. Low C3S and C2S contents in BOF slag make it a poor hydraulic binder. It may nonetheless, be used in soil stabilisation when activated by lime and other pozzolans. Heavy metals such as chromium, vanadium and nickel in the slag could potentially leach and pollute the environment. Assessment and monitoring of such elements are necessary for the environmental acceptance of using BOF slag in road pavements.
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    Open Access
    Effects of Soldier-Ant Mound (SAM) on the Strength Characteristics of Lateritic Clay Soils
    (Sciencedomain international, 2014) Ogundalu, A.O.; Adeboje, A.O.; Adelaja, F.
    The aim of this work is to investigate the effect of Soldier-Ant Mound (SAM) on the strength characteristics of lateritic clay soils in order to improve their poor geotechnical properties for road pavement construction. Three soil samples were collected from a burrow pit along the Lagos-Ibadan Expressway, Lagos, Nigeria. The samples were mixed with Soldier-Ant Mound in various proportions (0%, 2%, 4%, 6%, 8% and10% by weight) and subjected to soil strength tests: Compaction tests, California Bearing Ratio (CBR) and Unconfined Compressive Strength tests at the University of Lagos, Nigeria between June 2012 and July 2013. Results obtained were compared with the natural soil and standard values. The Atomic Absorption Spectroscopy, AAS, gave the exchangeable cations present in the Soldier-Ant Mound as: Calcium (Ca2+), Magnesium (Mg2+), Sodium (Na+), Potassium (K+) and Aluminium (Al3+). The plasticity index decreased with increase in SAM content which signifies a reduction in any swelling and deformation that may take place. The maximum dry density, soaked CBR and Unconfined Compressive Strength all increased with increase in SAM content. The addition of 10% SAM content reduced the plasticity index by 7.5% (from 25.8% to 23.9%) and increased the maximum dry density of the clay soil from 1660kg/m3 to 1750kg/m3 which is considered satisfactory to excellent. The Optimum moisture content of the clay soil was reduced by about 15%. The addition of 10% SAM increased the soaked CBR by 85% (from 10.43% to 19.35%) while the unconfined compressive strength of the Lateritic Clay Soil increased by 122% (from 40.32kN/m2 to 89.36kN/m2). Soldier-Ant Mound significantly improved the engineering properties of Lateritic Clay Soil. The results indicate that there is a potential in the use of Soldier-Ant Mound for improving the strength characteristics of lateritic soils for road pavement construction and other earth works.
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    Open Access
    Engineering Properties of Unused and Cement Stabilized Used Lateritic Soils
    (University of Ilorin, 2013) Adeboje, A.O.; Olaniyan, O.S.; Oladeji, O.S.; Osuolale, O.S.
    The practice of building local housing units with laterite is common in Ogbomoso, Oyo State, Nigeria. This practice helps to reduce the rising cost of building construction. This paper investigates the engineering properties of both used and unused laterite soils with intent to reuse the laterite soil in construction of housing units. Disturbed samples of both used and unused laterite soils were investigated for engineering index, compaction and strength properties. Sieve analysis, atterberg limits, specific gravity, compaction, air-dry moisture content, triaxial compression and compressive strength tests were performed on the samples of two types of soils in accordance with BS 1377-2; 1990. The results from the study revealed that the geotechnical properties of the unused laterite soil samples are better than that of the used laterite soil samples, which supports their suitability and preference for construction of local houses than the used laterite soil samples. However the used laterite soil can be re-used or reutilized to build local houses in subtropics by addition of 0.5% Portland cement. Furthermore, addition of 0.75% Portland cement to the used laterite soil makes it stronger and more suitable for construction of housing units than the unused laterite soil.
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    Open Access
    Evaluation of Rice Husk Ash Stabilized Lateritic Soil as Sub-base in Road Construction
    (Sciencedomain international, 2015) Alabi, A.B.; Olutaiwo, A.O.; Adeboje, A.O.
    Laboratory experiments were conducted and the results were analyzed for rice husk ash (RHA) stabilization of laterite soils for utilization as sub base materials in road construction. The index properties classified the soils as (A­7) under the AASHTO soil classification scheme. The soils were stabilized with 2.5% increment between 5 ­ 12.5% of rice husk ash (RHA) by dry weight of soil. Performance of the soil­RHA was investigated with respect to compaction characteristics, California bearing ratio (CBR) and unconfined compressive strength (UCS) tests. Addition of RHA decreased the maximum dry density while it increased the optimum moisture content at 5% RHA; the values of maximum dry density (MDD) and optimum moisture content (OMC) were 1962 kg/m³ and 24% respectively. California Bearing Ratio results showed that the peak CBR (soaked) value was 135.5% (for 7.5% RHA stabilization) which indicates 92.44% increase over the CBR value obtained for the laterite soils in their natural form. The lowest CBR (soaked) value occurred at 12.5% RHA stabilization. The unconfined compressive strength test results showed that the strength for natural soil was 107.32N/mm² and the highest UCS value for the stabilized soil was 68.82% (the value obtained for 5% stabilization using RHA). This gives 40.5% decrease in the UCS of the natural soil. This research shows little potentials of using RHA only for soil improvement, it is recommended that 5% of RHA be added to soil samples for field stabilization for the purpose of improving the soil engineering properties of the laterite soil for pavement sub­base construction. To achieve high pozzolanic behavior, it is recommended that RHA intended for use in stabilization are calcined burnt between 600ºC and 700ºC temperature.
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    Open Access
    Fracture Mechanisms and Failure Modes in Biocomposites and Bionanocomposites
    (Nova Publisher, 2017-07) Sadiku, E.R.; Agboola, O.; Ibrahim, I.D.; Olubambi, P.A.; Avabaram, B.R.; Bandla, M.; Kupolati, W.K.; Tippabattini, J.; Varaprasad, K.; Agwuncha, S.C.; Oboirien, B.O.; Phiri, G.; Nkuna, C.; Durowoju, M.O.; Owonubi, S.J.; Fasiku, V.O.; Aderibigbe, B.A.; Ojijo, V.O.; Biotidara, O.F.; Adeboje, A.O.; Adekomaya, O.S.; Aderibigbe, I.; Jamiru, T.; Dludlu, M.K.
    There are various mechanisms that can be responsible for material fracture which can ultimately lead to failure and there are different modes of failure. More often, the quantification of the dominating failure mode and the attendant prevailing fracture mechanism is an arduous task, even though this is of significant importance for the purposes of design. The deformation of a material can lead to any of three fracture mechanisms, which include: (a) elastic, leading to linear-elastic fracture mechanisms, (b) plastic, leading to elastic-plastic fracture mechanisms and (c) viscoelastic/visco-plastic, leading to creep fracture mechanisms. Failure behaviour of a material can be of three types, viz. (i) ductile, which can lead to either shear or dimple fracture, (ii) brittle which can lead to a cleavage fracture or a rupture and (iii) creep, which can lead to a creepfracture or normal/shear fracture. For fracture to occur, there must be some sort of material loading. Loading can be in the form of: (1) cyclic, leading to fatigue fracture, (2) static, leading to forced fracture, (3) dynamic, leading to fast fracture and (4) chemical, leading to stress corrosion cracking or fatigue corrosion cracking. These mechanisms and the different modes of fracture shall be discussed, in particular, for biocomposites and bionanocomposites, as these parameters (type of fracture mechanism, type of failure and type of loading) and, of course, the design protocols collectively determine the eventual performance of any material.
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    Open Access
    Influence of partial substitution of sand with crumb rubber on the microstructural and mechanical properties of concrete in Pretoria, South Africa
    (International Journal of Environment and Waste Management - Inderscience, 2019) Adeboje, A.O.; Kupolati, W.K.; Sadiku, E.R.; Ndambuki, E.R.
    Utilisation of waste materials such as crumb rubber for construction purposes is still in the formative stage in Africa. Experimental evaluation is required to encourage the use of crumb rubber for concrete production. The engineering properties of modified crumb rubber concrete were evaluated by substituting 1, 2, 3 and 4% sand content with crumb rubber. The concrete samples were investigated with slump, bulk density, compressive and tensile splitting strengths, energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) tests. The results showed that very small quantity of crumb rubber can improve both the microstructural and mechanical properties of concrete, however, utilisation of large quantities of crumb rubber can reduce the mechanical and microstructural properties of concrete. Implementation of crumb rubber as a substitute for sand in concrete can sanitise and conserve the environment, reduce haphazard disposal of waste tyre rubber and enhance conversion of waste tyre rubber to wealth.
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    Open Access
    Nanotechnology in Paints and Coatings
    (Wiley, 2018-11-16) Sadiku, E.R.; Agboola, O.; Ibrahim, I.D.; Olubambi, P.A.; Avabaram, B.R.; Bandla, M.; Kupolati, W.K.; Tippabattini, J.; Varaprasad, K.; Agwuncha, S.C.; Mochane, J.; Daramola, O.O.; Oboirien, B.; Adegbola, T.A.; Nkuna, C.; Owonubi, S.J.; Fasiku, V.O.; Aderibigbe, B.; Ojijo, V.; Dunne, R.; Selatile, K.; Makgatho, G.; Khoathane, C.; Mhike, W.; Biotidara, O.F.; Dludlu, M.B.; Adeboje, A.O.; Adeyeye, O.A.; Ndamase, A.; Sanni, S.; Molelekwa, G.F.; Selvam, P.; Nambiar, R.; Perumal, A.B.; Jayaramudu, J.; Iheaturu, N.; Diwe, I.; Chima, B.
    The protection of surfaces, especially metals, ceramic, glass, fabric, wood, and mineral surfaces, from stain, scratch, water absorption, etc, is best accomplished by going the nanotechnology route, via nanohydrophobic coatings. These coatings are sprays on liquids that will protect the surfaces of materials. Such exercise provides benefits, among others: good waterproofing and stain repellent, resistance to scratch, oleophobic and superhydrophobic features. Ordinarily, paints are liquids that are employed to coat a solid surface in order to protect, seal, or color such solid surfaces. Therefore, paints containing nano-silicon dioxide (nano-SiO2) do improve the macro- and microhardness, abrasion, scratch, and weather resistance, while nano-titanium dioxide (nano-TiO2) in addition to paints can significantly improve photocatalytic activity and also advance the material’s UV protection. Paints containing nanosilver (nanoAg, i.e., Ago) particles inclusion provide an astonishing antimicrobial properties against bacteria and human pathogens, even though nanosilver and nano-titanium dioxide may not fully prevent microbial and algal growths.
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    Open Access
    Polyhydroxyalkanoates as scaffolds for tissue engineering
    (Nova Publisher, 2018) Sadiku, E.R.; Fasiku, V.O.; Owonubi, S.J.; Mukwevho, E.; Aderibigbe, B.A.; Lemmer, Y.; Abbavaram, B.R.; Manjula, B.; Nkuna, C.; Dludlu, M.K.; Adeyeye, O.A.; Selatile, K.; Makgatho, G.; Ndamase, A.S.; Mabalane, P.N.; Agboola, O.; Sanni, S.; Varaprasad, K.; Tippabattini, J.; Kupolati, W.K.; Adeboje, A.O.; Jamiru, T.; Ibrahim, I.D.; Adekomaya, O.S.; Eze, A.A.; Dunne, R.; Areo, K.A.; Jayaramudu, J.; Daramola, O.O.; Periyar Selvam, S.; Nambiar, Reshma B.; Perumal, Anand B.; Mochane, M.J.; Mokhena, T.C.; Iheaturu, Nnamdi; Diwe, I.; Chima, Betty
    Tissue engineering is a field that has gained a lot of advancement since the discovery of biopolymers. Biopolymers are polymers produced by living organisms; that is, they are polymeric biomolecules. They consist of monomeric units that are covalently bonded to one another in order to form larger structures. Biopolymers have been widely used as biomaterials for the construction of tissue engineering scaffold. Scaffolds have been used for tissue engineering, such as: bone, cartilage, ligament, skin, vascular tissues, neural tissues, and skeletal muscles. Polyhydroxyester is a typical example of biopolymers that have been employed for this application. Their exceptional properties such as high surface-to-volume ratio, high porosity with very small pore size, biodegradation, and mechanical property have made them gain a lot of attention in this field. Also, they have advantages which are significant for tissue engineering. This chapter will focus on the production, modification, properties and medical applications of polyhydroxyesters, such as PLA (Polylactide), PGA (Polyglycolide or poly(glycolic acid)), PCL (Polycaprolactone), poly(ester amide)s and PLGA (Poly(lactide-co-glycolide), with particular emphasis on the different polyhydroxyalkanoates (PHAs), which have diverse applications in tissue engineering.