http://www.iaeme.com/IJARET/index.asp 492 editor@iaeme.com International Journal of Advanced Research in Engineering and Technology (IJARET) Volume 11, Issue 12, December 2020, pp. 492-503, Article ID: IJARET_11_12_053 Available online at http://www.iaeme.com/IJARET/issues.asp?JType=IJARET&VType=11&IType=12 ISSN Print: 0976-6480 and ISSN Online: 0976-6499 DOI: 10.34218/IJARET.11.12.2020.053 © IAEME Publication Scopus Indexed PREDICTION OF FLEXURAL STRENGTH OF EXPANDED POLYSTYRENE LIGHTWEIGHT CONCRETE USING SCHEFFE'S MODEL Ubi, S. E. Department of Civil Engineering, Faculty of Engineering, Cross River University of Technology, Calabar, Nigeria Okafor, F. O. Department of Civil Engineering, Faculty of Engineering, University of Nigeria, Nsukka, Nigeria Mama, B. O. Department of Civil Engineering, Faculty of Engineering, University of Nigeria, Nsukka, Nigeria Agbor R.B Environmental Biotechnology Unit, Department of Genetics and Biotechnology, University of Calabar, Calabar, Nigeria ABSTRACT This research examined the optimization of flexural strength of expanded polystyrene lightweight concrete mix. The work applied Scheffe’s optimization technique for a five by two degree polynomial. This linear optimization technique assumed the proportions of the material components of concrete to be variables in, x and that these proportions sum up to a whole, that is, unity. It obtained a mathematical model of the form f (X 1, X 2, X 3, X 4, X 5 ) where, j = 1, …5 are proportions of the concrete components namely; cement, sand, polystyrene, coarse aggregates and water/cement ratio. The polystyrene-cement blended proportions were mathematically optimized by using Scheffe’s approach and the optimization model developed. The optimal proportion by the program was used prepare beam samples measuring 150mm x 150mm x 750mm which were tested for flexural strength at 28 days and their results were compared with those of a standard 1:2:4 concrete mix.