Civil Engineering

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    Combined reusing of sorghum husk ash and recycled concrete aggregate for sustainable pervious concrete production
    (2022) Tijani, M.A; Ajagbe W.O; Oluwole, A.A
    The huge amounts of natural resources and high level of energy consumption in concrete production necessitate the use of agricultural and demolition wastes as alternative construction materials. The present study explores pervious concrete (PC) that includes sorghum husk ash (SHA) and recycled concrete aggregate (RCA) as alternatives to cement and natural aggregate (NA) in standard PC mixtures. PCs were prepared from mixtures derived from replacement levels 0%, 5%, 10%, 15%, 20% and 25% of cement with SHA and 0%, 20%, 40%, 60%, 80% and 100% of NA with RCA. The density, compressive strength and hydraulic properties (void ratio and hydraulic conductivity) of the samples were determined at 28-day using ACI standards. Sustainability efficiency of incorporating SHA and RCA on PC was also investigated using structural efficiency and carbon dioxide (CO2) emission. Their cost effectiveness was equally examined. Results revealed that densities of PC decreased with increase in SHA and RCA amount. Compressive strength and structural efficiency reduced with increase in SHA except at 5% where they were higher than the control. On the other hand, the incorporation of RCA decreased the compressive strength but improved the PC hydraulic properties. CO2 emission and production cost were found reduced with increase in SHA as well as RCA. The maximum reduction of CO2 emission (38.23%) and production cost (51.29%) were obtained when 25% SHA was combined with 100% RCA. The combined usage of SHA and RCA as raw materials in PC was found to be effective in boosting PC’s hydraulic properties at an appropriate compressive strength. The reduction of CO2 discharge and in production cost attributed to the construction materials demonstrates their impacts on mitigating global warming problems and lowering costs of PC production.
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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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    Strength properties of self-compacting concrete incorporating iron ore tailings
    (2023) Ajagbe W.O; Okpanachi R.O; Ganiyu A.A; Abdulkareem M.O
    The quest for sustainable production of concrete is a major step towards achieving netzero Carbon. The utilisation of industrial waste in the production of concrete entrenches both sustainability and economic viability. Iron Ore Tailings (IOT) are a byproduct of the beneficiation process of iron ore. The unbridled disposal of Iron Ore Tailings (IOT) has proven to be a great threat to the natural environment. Self-compacting concrete (SCC) has gained prominence in the construction industry based on its unique flowability quality. This study investigated the strength characteristics of SCC incorporating IOT as replacement for fine aggregate. Concrete containing 5%, 10%, 15%, 20%, 30%, 40%, and 100% IOT as fine aggregate replacement were prepared and subjected to compressive and flexural strengths tests. The results reveal a progressive increase in strength with age for compressive strength, and progressive increase in strength with increasing percentage contents of IOT for both compressive and flexural strength tests. The inclusion of IOT as partial replacement of fine aggregates in SCC has a potential to mitigate the environmental degradation caused by its disposal and excessive depletion of natural sand. Besides, it is a viable measure towards reduction of carbon footprint of concrete production with evident economical benefits.
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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.