Browsing by Author "Abubakar, J."

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Empirical Relationship between Compressive, Flexural and Splitting Tensile Strengths of Concrete Containing Kuta Gravel as Coarse Aggregate
(Journal of Engineering Research and Reports, 2025-02-02) Abubakar, J.; Abdullahi, M.; Aguwa, J. I.; Abbas, B. A.; Kolo, D. N.
Flexural and tensile strengths of concrete are of great importance in structural engineering. Understanding the flexural strength of concrete helps designers prevent and control development of cracks in concrete elements, ensuring durability. In addition to serviceability, shear, bond failure and flexural capacity in concrete members are directly linked to the tensile strength of the concrete. When compared to flexural and tensile strengths, determination of the compressive strength of concrete is easier to carry out in the field. It is therefore, customary to determine the compressive strength and correlate it to other strength properties. In this study, empirical relationships have been developed to relate the compressive strength to the flexural and splitting tensile strengths of concrete using Kuta river gravel as coarse aggregate. Using varying total aggregate to cement, coarse aggregate to total aggregate and water to cement ratios, 20 mixes were generated using Central Composite Design (CCD) in Minitab 21. The compressive, flexural and splitting tensile strengths of concrete samples from these mixes were determined at 28 days of age. From the strength data obtained, regression equations were developed that relate the strength properties with the aid of regression analysis tool in Microsoft Excel. The empirical models developed to predict the flexural and splitting tensile strengths of concrete from the compressive strength recorded R2 values of 1 for both models, P-values of 5.23 × 10−29 and 4.47 × 10−30, and standard errors of 0.21 and 0.06 respectively. Furthermore, residuals from the values of predicted strength properties show that there is very slight deviation between the experimental and predicted values. It was concluded that the empirical equations developed are significant, have high predictive capabilities and can be used in predicting the flexural and splitting tensile strengths of concrete.
Petrography and Geochemical Classification of the Saigbe Granites, North Central Nigeria
(Ilorin Journal of Science, 2022) Omanayin, Y. A.; Abubakar, J.; Owuri, A. S.
This work involves detailed field, petrographic and geochemical studies of Saigbe granites to bring forth their possible petrogenesis. Geological field mapping reveals the basement rocks of the Saigbe area consist of schist, amphibolite, and granite with minor intrusion of pegmatitic veins. Structural features were also discerned with principal joint direction as plotted on rose diagrams showing NWW – SEE for the granites. A total of ten granitic rock samples were collected and described based on their field relationships. Three fresh representative rock samples were subjected to petrographic analysis while five others were later subjected to geochemical analysis using the X-ray Fluorescence (XRF) technique. Petrography of the investigated rock samples showed an average mineralogical composition of plagioclase feldspar, quartz, biotite, microcline, muscovite and a trace of opaque minerals for the granites. The result of the geochemical analysis revealed the average percentage composition of major oxides as follows; SiO2 (71.30 wt.%), Al2O3 (11.13 wt.%), Fe2O3 (3.37 wt.%), CaO (4.44 wt.%), K2O (2.18 wt.%), Na2O (1.58 wt.%), MgO (2.09 wt.%), P2O5 (0.003 wt.%), TiO2 (1.04 wt.%) and MnO (0.62 wt.%). The geochemical classification of the granitic rocks revealed that the rocks fall within the Calc-alkaline/Tholeiitic series (AFM Plot), which supports a mixed and evolved magma origin during the evolution of the granitic rock. They were also classified into both I-Type and S-Type granite based on the Al₂O3/(Na₂O+K₂O+CaO) versus SiO2 plot. Ternary plot of the granitic samples sho.ws continent.al setting for the granitic rocks in the area. Therefore, the granitic rocks in the Saigbe area can then be said to have been formed from the fractionation of magma within the continental setting as the granitic rocks range in composition from Diorite and Granodiorite to Granite. Keywords: Petrographic Characteristic, Classification, Saigbe Granites, Nigeria