Civil Engineering

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Civil Engineering

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End date: 2019

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Now showing 1 - 10 of 10
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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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    Development of an Android Based Mobile Application for Design and Detailing of Pad Foundations to BS8110
    (Epistemics in Science, Engineering and Technology, 2017) Yusuf, A.; Aminulai, H. O.; Abdullahi, A.; Abubakar, Mahmud; Alhaji, B.
    Many innovative computer software have been developed to perform the task of designing and detailing structural elements such as beams, columns, slabs and foundations. This design and detailing can be done using mobile devices but software developed to operate on such devices have not been fully developed. However, this research is aimed at developing an android based mobile application for the design of pad foundations to Bs8110. The mobile application developed designs isolated axially loaded-only; axially loaded with moment pad footings as well as combined pad footings. The mobile application developed was tested using three typical test parameters and results compared to the manual computations. There was no significant variation in the steel sections required and provided for the manual design and that generated by the mobile application. The steel required by manual design for the axially loaded pad footing was 835mm2/m and that generated by the application was 837.2mm2/m. That of the axially loaded with moment gave required steel section as 1019mm2/m using manual design. This android based mobile application would thus give the structural engineer the leverage to design pad footings anywhere and anytime.
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    COMPARATIVE ANALYSIS OF TRAFFIC PERFORMANCE OF SMALL AND LARGE CENTRAL ISLAND ROTARIES IN MINNA, NIGERIA
    (SAVAP International, 2013) Abubakar, Mahmud; Ndoke, P. N.
    Of recent, the government of Niger state has embarked on the construction of roundabouts with small central island rotaries; this paper compares the performance of large central island rotaries with small central island rotaries. The performance of large central island rotaries compares well to the performance of small central island rotaries. Capacities of rotaries with small islands were found to be higher than capacities of large central island rotaries while the delay for large central island rotaries was found to be higher than that of small central island rotaries. However, both large and small central island rotaries were found to be operating at the same level of service. This study provides recommendations to traffic engineers and/or planners on the conditions under which both central island rotaries perform better and, thus, should be considered.
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    DEVELOPMENT OF AN ANDROID BASED MOBILE APPLICATION FOR THE DESIGN AND DETAILING OF ISOLATED PAD FOUNDATIONS ACCORDING TO EUROCODE 2
    (i-manager’s Journal on Mobile Applications & Technologies, 2019) Yusuf, Abdulazeez; Isiaka, I.; Abubakar, Mahmud; Aminulai, H. O.; Abdullahi, Aliyu; Alayande, T. A.
    In a building construction project, it is the responsibility of the structural engineer to come up with a complete design of all structural elements. When this is done manually it is tasking, time consuming, and produces errors with inconsistent results. However, the design can be done using computer software, but this also comes with some downside; it is expensive and complex to use. Thus, this research developed an android based mobile application for the design of pad foundations to Eurocode 2 to put these challenges in check when designing pad footings. The mobile application designs isolated Axially loaded-only and Axially loaded with bending pad footing to Eurocode 2 accurately, with consistent results and in a timely manner. The application was tested using typical test parameters and results are compared to the manual computations. There was no significant difference in the steel sections provided for both methods. All checks that must be satisfactory in design were all checked and found to be satisfactory.
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    Probability based design of concrete mixes with cow-bone ash admixed cement
    (Leonardo Journal of Sciences, 2017) Abubakar, Mahmud; Mohammed Abdullahi; James Isiwu Aguwa
    A probability-based procedure for design of concrete mixes with cow-cone ash admixed cement has been developed considering the strength as a random variable. However, the compressive strength of concrete in turn, depends on the properties of its constituent materials: cement, fine aggregate, coarse aggregate and cow-bone ash. The compressive strength data generated experimentally has been analysed using normal-probability distribution functions based on 95% confidence interval. The proposed probability based design was compared to the method of trial mixture. It was observed that for reliability index (β) of 1.3, the proposed probability methodology uses 10.2% less cement content than the method of trial mixture; thus, indicating that the method is conservative. It was also observed that, for concrete grade 25, the proposed methodology gives higher compressive strength at both 7 and 28 days. Hence, the probability-based design procedure was found appropriate and is therefore recommended for the design of concrete mixes with cow-bone ash admixed cement.
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    Comparative Assessment of Macroscopic Traffic Flow Properties Estimation Methods: A Case for Moving Car Observer Method
    (ENGINEERING SCIENCE AND TECHNOLOGY INTERNATIONAL RESEARCH JOURNAL, 2017) Hassan Shuiabu Abdulrahman; A. A. Almusawi; Abubakar, Mahmud
    Different methods of estimating macroscopic traffic properties is expected to have varying results even when they are carried out on the same road and during the same time interval. A comparative assessment was carried out between traffic data collected at a point and that collected over a short section; Moving car observer method(MCO). Student’s t-test was used to evaluate both data and it was observed that there was no significant difference between them. The MCO method correlates well with conventional data collection method and it can be used as a substitute for it, assuming conventional data collection method is true
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    Effect of Partial Replacement of Fine Aggregate with Sawdust in Light Weight Concrete Production Using Bida Natural Stone as Coarse Aggregate
    (Proceedings of the 3rd International Engineering Conference, Federal University of Technology Minna, Nigeria, 2019) Alhaji, B.; Abubakar, M.; Yusuf, A.; Oritola, S. F.; Mohammed, S.; Kolo D. N.
    This study investigated the effect of sawdust as partial replacement for Fine Aggregate in light weight concrete production. Sawdust was used to replace Fine Aggregate from 0% to 40% in steps of 5%. 150 x 150 x 150mm concrete cubes were cast for each replacement level, the concrete was cured and the compressive strengths were determined at 7, 21 and 28days curing period respectively. Increase in percentage of sawdust in concrete stant reduction in the compressive strength values with a corresponding reduction in weight. From the result obtained, 5% replacement of Fine Aggregate with sawdust gave a maximum compressive strength 13.11 N/mm2. It was however concluded that the optimum replacement level of 5% can be used as plain concrete for blinding works.
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    Partial Replacement of Fine Aggregate with waste Glass in Concrete made from Bida Natural Aggregate
    (. Proceedings of the 3rd International Engineering Conference, Federal University of Technology Minna, Nigeria, 2019-02-05) Alhaji, B.; Kolo, D. N.; Abubakar M.; Yusuf A.; Abdullahi, A.; Shehu, M.
    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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    Durability Characteristics of Lateritic Subgrade Treated with Iron Ore Tailings and Lime Exposed to Moisture Fluctuations
    (. Nigeria Journal of Engineering and Applied Sciences (NJEAS), 2018-02-11) Mohammed, A. M.; Amadi, A. A.; Aguwa, J. I.; Kolo, D. N.
    This research evaluated the durability of lateritic subgrade treated with Iron Ore Tailings (IOT) and lime exposed to moisture variations. Representative sample of the subgrade was treated with 0, 5, 10, 15, and 20% IOT and optimal lime percent (6.2%) determined through Eades and Grim pH test. Preliminary tests such as particles size distribution, Atterberg limits and compaction were conducted to characterize the mixtures while Unconfined Compressive Strength (UCS) and CBR-swell tests were carried out to access durability of the soil mixtures. Addition of lime to the soil increased the liquid limit to 45% from 36% obtained in natural soil. Similarly, the plastic limit of the lime-treated sample increased from 16 to 26% with reduced plasticity index. While the natural soil exhibited CBR of 3 and 75% for soaked and unsoaked specimens respectively, the value increased and peaked at 11 and 118% with addition of lime and 15% IOT. Durability of the soil improved with addition of IOT and lime. 15% IOT and lime treated soil recorded the best results with UCS of 240 kN/m2 and 200% Relative Volumetric Stability (RVS), which is a measure of strength loss of a soil. Similarly, swell value of 0% was recorded when the lime-IOT samples were subjected to CBR-Swell test. This shows that the lime-IOT treated samples are less vulnerable to moisture condition normally prevalent in the pavement subgrades.
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    Development of Sensitivity based Model for Flexural Failure of Singly Reinforced Concrete Slabs Based on BS 8110: 1997
    (. Nigeria Journal of Engineering and Applied Sciences (NJEAS), 2017-03-22) Tsado, T.Y.,; Sadiku, S.,; Iorkar, A.; Kolo, D. N.
    This research presents mathematical models for checking the effect of variation in key designed parameters on the structural collapse of singly reinforced concrete solid slabs in buildings due to flexural failure based on British Standard (BS) 8110, 1997. The increasing complexity of construction process requires very high level of engineering and management skills to combat the structural collapses widely experienced globally. Most of the collapses were adjudged to be due to improper management arising from variations in structural key design parameters during construction, and this call for mathematical models to check the effect of variation in key design parameters on the structural collapse. The key design parameters considered in this research are; characteristic strength of reinforcement, grade of concrete, diameter and spacing of tension reinforcement, effective depth of tension reinforcement, applied moment. Sensitivity analysis was applied to study the effect of variation in the key parameters on the moment capacity. The results of sensitivity analysis were utilized in regression analysis to develop simplified equations for estimating the moment capacity of the slab. Computer programme was developed based on BS 8110, 1997 standard using Java to verify the model. Flexure safety factor was also checked based on BS 8110, 1997 requirements. Forty five numerical examples were taken to validate the model with the developed computer programme at 5% significance level using Chi-squared as an instrument for sensitivity-based model for flexural failure of singly reinforced concrete slab. The results show that the model is adequate at 5% significance level for checking flexural failure of singly reinforced concrete slab at construction stage based on BS 8110, 1997. It was recommended that the construction practitioners should consider the diverse effect of change in key deigned parameters during construction, otherwise the developed model should be strictly considered for quick safety check especially deflection safety of a solid slab during construction.