School of Infrastructure Process Engineering and Technology (SIPET)

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School of Infrastructure Process Engineering and Technology (SIPET)

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Author: search.filters.author.Abubakar, MahmudSubject: search.filters.subject.Concrete

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    Statistical Model for Predicting Slump and Strength of Concrete Containing Date Seeds
    (Covenant Journal of Engineering Technology (CJET), 2021) Yusuf, A; Jamal, J. O.; Abubakar, Mahmud; Aminulai, H. O.
    Incorporating agro-based waste in concrete can reduce environmental pollution and lead to preserving the ecosystem. In order to reduce trial and error in achieving desired slump and compressive strength of concrete containing Date Seed (DS), this paper examines the slump and compressive strength of concrete using date seeds as a partial replacement for crushed granite. Preliminary tests were conducted on the aggregates to ascertain their suitability for concrete production. Concrete with DS-crushed granite ratios of 0:100, 5:95, 10:90, 15:85, and 20:80 were prepared using a mix ratio of 1:2:4 and a water-cement ratio of 0.5. Slump loss was used to estimate the workability of the fresh concrete. The freshly prepared concrete was cast in 150 x 150 x 150 mm and the compressive strength was determined after curing by full immersion in water for 7, 14, 21 and 28 days. Results showed that the slump of concrete increased with an increase in the content of date seed. The compressive strength was inversely proportional to the date seed content with a DS crushed granite ratio of 20:80 recording the lowest compressive strength (20N/mm2). Linear regression models for slump and compressive strength were developed and found to be sufficient in explaining the experimental data based on a Mean Square Error (MSE) of 0.37 and 0.029 and R2 of 88% and 99% obtained for slump and compressive strength respectively. The study has concluded that DS can be used as a partial replacement for crushed granite in concrete and a linear model is sufficient in predicting the slump and strength of concrete containing date seeds.
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    PARTIAL REPLACEMENT OF FINE AGGREGATE WITH WASTE GLASS IN CONCRETE MADE FROM BIDA NATURAL AGGREGATE
    (3rd International Engineering Conference (IEC 2019) Federal University of Technology, Minna, Nigeria, 2019) Alhaji, B.; Kolo, D. N.; Abubakar, Mahmud; Yusuf, A.; Abdullahi, A.; Mohammed, S.
    This study reports the experimental investigation on the suitability of waste glass as partial replacement for fine aggregate in concrete made using Bida natural aggregates (BNA). Glass is widely used in our daily lives through manufactured products such as sheet glass, bottles, glassware, and vacuum tubing. It is an ideal material for recycling. The increasing awareness of glass recycling speeds up inspections on the use of waste glass with different forms in various fields. Mix ratio of 1:2:4 batched by weight with water – cement ratio of 0.55 was used. The percentage replacement varied from 0% to 40% at 5% intervals. Slump test was conducted to assess the workability of the fresh concrete. The compressive strengths and densities of cured concrete cubes of sizes 150mm x 150mm x 150mm were evaluated at 7, 21 and 28days. A total of 81 concrete cubes were cast and tested. It was observed that an increase in the percentage replacement of fine aggregate with waste glass reduces workability, density and compressive strength. The compressive strength and density vary with days of curing. The findings of this study indicated that the optimum replacement percentage of waste glass with conventional fine aggregate was 20%. However waste glass can effectively be used as fine aggregate replacement (up to 40%) without substantial change in concrete strength.
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    Reliability Studies on Reinforced Concrete Column Subjected to Axial Load with Natural Stone as Coarse Aggregate
    (NAUJournalofCivil Engineering (NAUJCVE), 2024) Kolo, D. N.; Aguwa, J. I.; Abubakar, Mahmud
    This paper presents the reliability assessment of a reinforced concrete column subjected to Axial loading. Locally available natural aggregate (NA) was used in concrete production, the results of preliminary tests revealed the aggregate was adequate for concrete production. A typical column cross section of 230 × 240 × 3000mm was adopted and probabilistically assessed. First Order Reliability Method (FORM) was employed to estimate the implied probabilities of failures. The results of the sensitivity analysis showed that the reinforced concrete column is structurally safe at length, breadth and depth of 3200, 240 and 230 mm with Probability of Failures of 1.14 ×10-3, 8.45 × 10-4and 8.45 × 10-4 respectively.