scholarly works

Permanent URI for this collectionhttps://repository.ui.edu.ng/handle/123456789/566

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Author: search.filters.author.Ajagbe W.OEnd date: 2019

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    Determination of appropriate mix ratios for concrete grades using Nigerian Portland-limestone grades 32.5 and 42.5
    (2015) Agbede O.A; Ajagbe W.O
    The construction of buildings by incompetent craftsmen and the use of low quality building materials, including low quality concrete have been identified in the literature as two of the major reasons for the incessant collapse of building in Nigeria. The roadside craftsmen/artisans usually/generally construct buildings using 1:2:4 cement-fine aggregate-large aggregate mix ratio irrespective of the cement strength class. In this paper, the investigation conducted to determine the appropriate concrete mix ratios required to produce Class 20/25 and Class 25/30 concretes commonly used for design of building structural members using the Portland-limestone cement grades 32.5 and 42.5 that are available in the Nigerian open market is presented. Investigation revealed that the cube compressive strength of 1:2:4 concrete produced with Portland-limestone cement grade 32.5 is less than the minimum 25MPa required for concrete Class 20/25 and a richer 1:1.5:3 concrete produced with Portland-limestone cement grade 32.5 may be needed to produce concrete Class 20/25. Investigation also revealed that Portland limestone cement grade 32.5 may not be suitable for the production of concrete class 25/30 with cube compressive strength of 30MPa as the cube compressive strength of 1:1:2 concrete produced with Portland-limestone cement grade 32.5 may not attain 30MPa. Concrete strength classes 20/25 and class 25/30 can be produced with Portland-limestone cement grade 42.5 using
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    Model tests on soil displacement effects for differently shaped piles
    (2018) Ganiyu A.A; Rashid . A.S.A; Osman M.H; Ajagbe W.O
    Transparent synthetic soil synthetic soil surrogates which permit real-time visualisation of soil continuum during testing is a novel development for geotechnical physical model tests. This paper presents model tests on pile penetration effects of differently shaped model piles subjected to axial loads in transparent synthetic soil model. Model piles, made of mortar of square, hexagonal, octagonal and circular shapes were utilised for the research. The transparent soil was made from fumed silica powder and pore fluid containing Paraffin and Technical White Oil. Soil displacement patterns were captured non-intrusively using close range photo grammetry while Particle Image Velocimetry (PIV) was employed to analyse the images. The analysed results revealed that the displacements of soil beneath the square pile aligned perfectly vertical with the edge of the pile, while it inclined with the vertical for piles of other shapes; this angle of inclination θ also varies for the variously shaped piles. This result, which depicts varying displacement patterns of soils beneath the differently shaped piles and marks distinguishable features for each shape of pile is significant. It could be used as the basis for the evolution of design charts and protocols based on shape of piles.
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    Analysis and Design of a Fully Submerged Underground Water Tank Using the Principle of Beam on Elastic Foundations
    (2015) Ajagbe W.O; Ilugbo E.O; Labiran J.O; Ganiyu A.A.
    The basic requirement in the design of reinforced water tank is to ensure it is crack free. This research studied the analysis and design of a fully submerged underground reinforced concrete water tank using the principle of beam on elastic foundations. To achieve this, a Microsoft Excel Spreadsheet Design and Analysis Program (MESDAPro) was generated for quick assessment of various moments of the tank, geometrical features and soil conditions for both full and empty conditions of the tank. It was observed that the wall moments, moment at base of wall and base slab moment decreases with increase in soil sub-grade modulus at constant capacity, height and breadth of the tank. However, wall moments, moment at base of wall and base slab moment increases with increase in height of the tank at constant value of sub-grade modulus, tank capacity and breadth. In all the examined cases, the moments obtained are higher when the tank is considered empty than when considered full
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    Environmental impact of rock blasting activities on adjoining structures and its inhabitants: A case study of landson quarry in Ibadn
    (2011) Ajagbe W.O; Akanmu. O.M.
    The impact of rock blasting activities on adjoining structures and on the health of the inhabitants was assessed by subjecting the inhabitants to administer structured questionnaire and response to simple questions concerning the state of their health. In addition, site reconnaissance survey, measurement of cracks on buildings and measurement of noise level were carried out. It was observed that the inhabitants are suffering from ailments traceable to the activities of the quarry in addition to general discomfort; the noise level being generated is approximately the same as the standard specified by the Federal Environmental Protection Agency. Also, it was discovered that the vibration generated from rock blasting is linked to some building collapse in the area while servicing ones are prone to collapse due to the high number of cracks on them. In conclusion, the sitting of quarry in residential area poses threats to both the structures and the people living in such area.