Chidobere D. Nwa-David; David O. Onwuka; Fidelis C. Njoku; Owus M. Ibearugbulem
Abstract
Statistical methods such as Scheffe’s and Osadebe’s models are commonly employed for the optimization of concrete properties. Despite their prediction suitability, attention ...
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Statistical methods such as Scheffe’s and Osadebe’s models are commonly employed for the optimization of concrete properties. Despite their prediction suitability, attention is drawn to their drawback. Ibearugbulem’s model has been developed to address these shortcomings. In this study, Ibearugbulem’s optimization method was employed to formulate a mathematical model for prediction and strength-optimization of nanostructured cassava peel ash (NCPA)-cement composite. The variation of 28 days compressive strength and initial and final setting time of NCPA-concrete was evaluated. Based on the establishment of a spatial domain for each concrete mixture variable, the response function is expressed as a multivariable function for the proportions of the constituent materials. Applying the variational approach, the response function was developed within the specified spatial domain and was optimized. There were 51 observation points. Twenty-six observation points were used to formulate the model and the remaining twenty-five points were used to test the adequacy of the formulated model. The observation points on the odd serial number are the ones selected for the formulation of the model. The ones on the even serial numbers are the ones used for testing the adequacy of the model. Fisher’s statistical tool was used in the analysis and the calculated value of fisher of 1.11 was lower than the fisher value of 1.94 derived from the statistical f-distribution table. This result proved that there was no significant difference between the laboratory compressive strength values and the modeled strength values at a 95% confidence level. This shows that the formulated model is reliable, safe, and recommended for concrete production.
