Optimization of the compressive strength of five-component-concrete mix using Scheffe’s theory –a case study of mound soil concrete

The paper presents the report of an investigation carried out to optimize some mechanical properties of a five-component-concrete mix. Mound soil (MS), randomly selected from some habitats of a common tropical specie of termites from Iyeke-Ogba, Nigeria was investigated as a fifth component in concrete. The work applied Scheffe’s optimization technique and obtained a mathematical model of the form f(x1,x2,.x3.x4, x5)where x, j = 1, 2, 3, 4, 5 are proportions of the concrete components namely; cement, fine aggregate, mound soil, coarse aggregates and water/cement ratio. Scheffe’s experimental design was followed to mould various cube samples measuring 150mm x 150mm x 150mm, with different ingredient components which were tested for 7, 14 and28 days strength. Software for the design of mound soil concrete (MSC) was proposed. The results show that the optimum mix was 1.00:1.59:0.46:3.34:0.53 with a compressive strength of 43.72N/mm2. The paper concludes that concrete can be designed as a five component mix in structural engineering rather than using admixtures in undersignedpercentages