Department of Civil Engineering, Federal University of Technology, P.M.B. 704, Akure, Nigeria; Ondo State Ministry of Works and Transport, Akure, Nigeria
Arum, C., Department of Civil Engineering, Federal University of Technology, P.M.B. 704, Akure, Nigeria; Adu, O.T., Ondo State Ministry of Works and Transport, Akure, Nigeria
This research assessed the quality of concrete produced at various sites in Akure, Nigeria with a view to determining its current margin. For this purpose, Akure metropolis was mapped into seven zones based on the magnitude of the on-going building construction activities. In each of the sites that emerged, standard concrete cubes of 150x150x150mm dimension were cast from supposed 1:2:4 nominal mixes prepared for each of the major structural elements (columns, beams, and slabs). All the concrete cubes were cured, and at the standard maturity age of 28 days, they were crushed for compressive strength. The statistics of the mean strengths and standard deviations, as well as the concrete margin were computed. The results of the investigation revealed the statistical parameters for concrete produced at various sites in Akure metropolis to be: computed characteristic strength - 14N/mm2, standard deviation - 2.5N/mm2, and concrete margin - 4.1N/mm 2 The implication is that the current practice of specifying 21 N/mm2 by concrete designers for concrete with nominal mix ratio 1:2:4 produced from normal sand and granite aggregates is rather ambitious under the current local concrete practice condition. © EuroJournals Publishing, Inc. 2011.