Optimization of Compressive Strength of Lime-Cement Concrete using Scheffe’s Regression Theory

Document Type : Original Article

Authors

1 Senior Lecturer, Department of Civil and Environmental Engineering, University of Port Harcourt, Rivers State, Nigeria Choba Rivers State

2 Senior Lecturer, Department of Civil and Environmental Engineering, University of Port Harcourt, Rivers State, Nigeria

Abstract

In this paper, a regression model is formed to make the fore-telling of the compressive strengths and their compactible mix ratios for a lime-cement concrete as effective and perfect as possible using the Scheffe’s regression theory. Twenty four selected mix ratios were studied experimentally for their compressive strengths at 28 days after curing in water at room temperature. Compressive strengths obtained stretched from 15.12N/mm2 to 24.58N/mm2. Fifteen of the readings obtained were used to develop the regression model while nine mix proportions were adopted for validation of the developed model. The model was tested for reliability at 95 % level of confidence using the F-statistic test and found to be adequate as the calculated F-value (1.918) was less than the critical F-value (3.438). A MATLAB based computer program was written based on the regression model using visual basic 6.0 software to optimize the compressive strength of the lime cement concrete and also speed up the process of selecting the corresponding mix ratios. The peak value of compressive strength predictable by the model is 24.460336 N/mm2 and the corresponding mix ratio is 0.586:0.841:0.159:2.42:4.84 (water: cement: lime: sand: granite chippings). MATLAB program developed is interactive, quick and is suitable for application in optimum concrete mixture proportioning.

Keywords


1-Wright, S. J., 2023, “Optimization” Encyclopedia Britannica, https://www.britannica.com/science/optimization.
2-Mahmoud, E. H., 2006, Overview of optimization, Process Systems Engineering, 7, 285-314.
3-Grytsenko, O. M., Pukach, P. Y., Suberlyak, O. V., Moravskyi, V. S., Kovalchuk, R. A.,  and Berezhnyy, B. V., 2019, The Scheffes method in the study of mathematical model of polymeric hydrogels composite structures optimization, Mathematical Modeling and Computing, 6, 2, 258-267.
4-Gamil, Y., Zamahri, K. A., and Bakar, I., 2018, Application of Scheffe’s theory to develop mathematical prediction model to predict UCS for hybrid containing organic soil and POFA-OPC additives, Civil Engineering and Architecture, 6, 2, 54-64, https://doi.org/10.13189/cea.2018.060202
5-Awodiji, C. T. G., Onwuka, D. O., Okere, C. E and Ibearugbulem, O., Anticipating the compressive strength of hydrated lime cement concrete using artificial neural network model. Civil Engineering Journal, 4, 12, 3005-3018, http://dx.doi.org/10.28991/cej-03091216
6-Salman, M. M and Mutter, A. A., 2017, The mechanical properties of lime concrete, Journal of Engineering and Sustainable Development, 21, 2, 180-191.
7-Awodiji, C.T.G., Awodiji, O. O and Onwuka, D. O., 2016, Re-investigation of the compressive strength of OPC concrete and lime concrete, International Journal of Geology, Agriculture and Environmental Sciences, 4, 1, 12-16.
8-Nwachukwu, K. C., Njoku, K. O., Okorie, P. O., Akosubo, I, S., Uzoukwu, C. S., Ihemegbulem, E. O., and Igbojiaku, A. U., 2022, Comparison between Scheffe’s second degree (5,2) and third degree (5,3) polynomial models in the optimization of compressive strength of glass fibre reinforced concrete (GFRC), American Journal of Computing and Engineering, 5, 1, 1-23.
9-Attah, I. C., Etim, R. K., Alaneme, G. U., and Bassey, O. B., 2020, Optimization of mechanical properties of rice husk ash concrete using Scheffe’s theory, SN Applied Sciences, 2, 928 | https://doi.org/10.1007/s42452-020-2727-y
10-British Standard Institution, BS EN 197, part 1, Composition, specification and conformity criteria for common cements, BSI, London, 2000.
11-British Standards Institution, BS 882: part 2, 1992, Grading limits for fine aggregates.  BSI, London, 1992.
12-Scheffe, H., 1958, Experiments with mixtures, Journal of Royal Statistical Society Series B, 20, 344 -360.
13-Onwuka, D.O., Sule, S., 2017, Prediction of compressive Strength of chikoko-cement concrete using Scheffe’s polynomial function, Journal of Research Information in Civil Engineering, 14, 1, 1338-1358.