Browsing by Author "TIJANI, M.A."

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    Effect of Variation in Physical and Mechanical Properties of Reinforcing Steel on Post-Construction Parameters of Buildings in Nigeria
    (2023) AJAGBE W.O.; TIJANI, M.A.; EZENMIA, C.M.; BABATUNDE L.A; GANIYU, A.A.
    The Nigerian market for construction materials has a problem of standardization as a massive range of variation in construction materials properties plagues the market. A larger number of these variations are below the accepted standards and a key material affected is reinforcing steel. This research aims to investigate the effect of variation in physical and mechanical properties of reinforcing steel on post-construction parameters (cost and safety margins) of buildings in Nigeria. Data on variation of selected properties was collected through extensive literature review and processed into tables showing the result of the input data on key building parameters. Data visualization was done using Microsoft Excel to help gain insights on trends and patterns. The trends and patterns observed informed the regression analysis carried out with Microsoft excel, aimed at establishing relationships between variable variations. A rebar optimization algorithm/software was developed to help optimize variation in standard rebar lengths and reduce waste on site, and was tested on five (5) project cases. The results show a wide range of variation for bar diameter and yield strength values, with some values falling as much as 30% below standard. The variation in young’s modulus was seen to be minimal and has the least effect on safety margins. Equations were generated from regression to predict effect of these variations on safety margins. The rebar optimization algorithm proved efficient in reducing waste and saving cost. The algorithm follows a recursive approach for problem solving. The variation in these properties have a significant effect on building safety and cost. The prediction formulae generated can be used by Engineers to track safety margins and the algorithm can help with waste reduction and cost saving on projects.
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    Properties of Hollow Sandcrete Blocks Produced from Ultrafine Carbon Particles Blended Cement
    (2023) AJAGBE W.O.; TIJANI, M.A.; AJUWON, M.O.
    This study investigated the properties of hollow sandcrete blocks produced from ultrafine carbon particles (UCP) blended cement. Waste radio batteries were obtained from electronic repairers and dumpsites in Osogbo. The carbon rod in the batteries were sorted and mechanically grinded to UCP. The UCP replacement levels of 1, 2, 3, 4 and 5% were used. A total of 36 hollow sandcrete block specimens of dimension 450 × 225 × 150 mm were cast using mix ratio 1:5 to undergo density, water absorption and compressive strength tests at 7 and 28 days of curing respectively. The densities of the control, 1, 2, 3, 4 and 5% UCP were 1136, 1169, 1152, 1158, 1154 and 1152 kg/m3 at day 7, and 1063, 1093, 1106, 1128, 1134 and 1142 kg/m3 at day 28 respectively. Their respective water absorption were 6.0, 5.3, 5.0, 3.0, 2.8 and 2.0% at day 7 and 12.0, 10.0, 7.0, 6.0, 5.0 and 2.4% at day 28. The water absorption for all the mixtures were within the BS specification of 12% maximum. The 28 day compressive strength increased by 15.48, 19.01, 25.26, 20.52 and 16.47% for 1, 2, 3, 4 and 5% UCP replacement respectively. It is concluded that UCP can be used to improve the compressive strength of sandcrete blocks at acceptable density and water absorption.