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)

Abstract

Purpose: This research work aimed at formulating an optimization model based on  Scheffe’s Third Degree Polynomial (5,3)  that can be used to optimize the compressive strength of Glass Fibre Reinforced Concrete (GFRC), which is then compared to Scheffe’s Second  Degree Polynomial (5,2) formulation developed by Nwachukwu and others (2017) . Methodology: Using Scheffe’s Simplex method, the compressive strength of GFRC was determined for different ratios.  Control experiments were also carried out and the compressive strength determined. After the tests have been conducted, the adequacy of the model was tested using fisher’s f-test and the result of the test shows a good correlation between the model and control results.  Findings: Optimum compressive strength for the Scheffe’s (5,3) model was  obtained as 21.82 N/mm2. This is slightly higher than the optimum compressive strength for Scheffe’s (5,2) model which was obtained as 20.71 N/mm2 by Nwachukwu and others (2017). Since structural concrete elements are generally made with concrete having a compressive strength of 20 to 35 MPa (or 20 to35 N/mm2 ), it then means that optimized GFRC based on both Scheffe’s models  can produce the required compressive strength  needed in major construction projects such as bridges and  light-weight structures. Recommendations: Major stakeholders in the construction industry are therefore advised to use optimized GFRC as it is far cheaper and still possess the required strength needed for construction works.