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Item Effect of Addition of Calcium Nitrate on Selected Properties of Concrete Containing Volcanic Ash(Leonardo Electronic Journal of Practices and Technologies, 2011) OGUNBODE, Ezekiel Babatunde; HASSAN Ibrahim OgiriAbstract In this work, the effect of addition of Calcium Nitrate on selected properties of concrete containing Volcanic ash as partial replacement for ordinary Portland cement by weight was investigated .The study carried out used 10% volcanic ash as partial replacement and an admixture, Ca(NO3)2 Was added to improve the strength of the resulting concrete at 2%, 4%, 6% 8% and 10% respectively. The result of setting time showed a decrease in both initial and final setting time of the mixture as the Ca(NO3)2 Content was increased. The result of chemical analysis of volcanic ash showed an increase in calcium oxide (CaO) content when calcium Nitrate Ca(NO3)2 was added from 11.67% to 33.68%. Cubes were cast and cured in water for 7, 14, 21, and 28 days .The resulting Strength at 28 days hydration period shows a strength increase as the percentage of Ca(NO3)2 was increased to 10% .Item Effect of Aggregate Washing on Compressive Strength of Concrete produced Using Bida Natural Stone(Proceedings of the 2nd International Civil Engineering Conference, Department of Civil Engineering, Federal University of Technology Minna, Nigeria., 2020-02-01) Kolo, D. N.; Aguwa, J. I.; Tsado, T. Y.; Alhaji, B.; Joseph, O. F.Concrete is the most widely used construction material in the world, second to water as the most utilised substance on earth. Coarse aggregate is an essential component in concrete production; it has effect on the workability and mechanical properties of concrete. Bida Natural Stone (BNS) which is the by-product of Precambrian deposits of Bida trough was used as coarse aggregate, utilising unwashed and washed aggregates. A total of 80 concrete cubes of 150 × 150 × 150 mm were cast and used for this study, compressive strength tests were conducted after 28 days curing. The result of physical properties test conducted proved that BNS is suitable for concrete production. The result of compressive strength tests conducted shows that concrete produced using washed aggregate results in an increase in average compressive strength of about 11.46 % when compared to that produced using unwashed aggregate. Hence, construction professionals and workers utilising this aggregate (BNS) in the Bida basin are encouraged to practice aggregate washing before concrete works.Item Reliability Studies on Reinforced Concrete Column Subjected to Axial Load with Natural Stone as Coarse Aggregate(Nnamdi Azikiwe University Journal of Civil Engineering (NAUJCVE), 2024-01-02) Kolo, D. N.; Aguwa, J. I.; Abubakar, M.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 × 10-4 and 8.45 × 10-4 respectively.Item Reliability studies on reinforced concrete beam subjected to bending forces with natural stone as coarse aggregate(Asian Journal of Civil Engineering, 2020-01-12) Kolo, D. N.; Aguwa, J. I.; Tsado, T. Y.; Abdullahi, M.; Yusuf, A.; Oritola, S. F.This paper presents the results of structural reliability analysis of a structural element (beam) in building using First-order reliability method (FORM) to ascertain the level of safety. The natural stone (NS) which is the by-product of Precambrian deposits of the Bida trough was used as coarse aggregate: unwashed and washed aggregates were used. A total of 80 concrete cubes of 150 mm × 150 mm × 150 mm were cast and used for this study, sensitivity analysis was conducted by varying the span, depth, effective depth, area of shear reinforcement and dead load of the beam in bending. The result of the sensitivity analysis revealed that the beam utilising unwashed and washed NS are both structurally safe at a span of 3000 mm with probabilities of failure of 9.20 × 10–5 and 2.06 × 10–8 and both safe at a depth of 600 mm with probabilities of failure of 4.19 × 10–4 and 2.602 × 10–4, respectively, in bending.