Civil Engineering
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Civil Engineering
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Item Flexural Strength of Revibrated Concrete Using Iron Ore Tailings (IOT) as Partial Replacement for River Sand(Journal of Research Information in Civil Engineering,, 2020-10-10) YUSUF, Abdulazeez; A. I. EmmanuelRiver sand is one of the major concrete constituents. Sand mining from rivers results in several environmental problems which leads to destruction of river banks among others. The use of IOT as a substitute for river sand is capable of addressing this problem. The effect of partial replacement of river sand with IOT on the flexural strength of revibrated concrete was studied in this paper. Sieve analysis, bulk density specific gravity and water absorption tests were conducted on the IOT, river sand and crushed granite to ascertain their suitability for use in concrete. A mix ratio of 1:2.1:2.7 and water-cement ratio of 0.5 was used to prepare concrete mixes with 0%, 10%, 20%, 30%, 40%, 50%, and 100% IOT as sand replacement. A total of 63 prisms of size 100 x 100 x 500 mm were cast and revibrated 30s for 3 minutes within 1 hour to provide samples to be tested for flexural strength at 7, 14 and 28 days curing age. Results revealed that the workability of concrete decreased with increase in percentage of IOT. Highest flexural strength was noted with concrete containing 100% IOT at all curing ages. Flexural strength model was proposed as a function of % IOT at 28 days curing age. It was recommended that IOT can be used as either partial or total replacement for river sand in concrete.Item 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.