Mathematical model for the prediction of the compressive strength characteristics of concrete made with granite chippings

Abstract

The coarse aggregates used in this research work were granite chippings from Abakaliki in Ebonyi State and fine aggregates from
Amansea River in Anambra State. These aggregates were tested for their physical and mechanical properties based on BS 812:
Part 2:1975 and BS 812: Part 3: 1975. Concrete cubes were made, cured and tested according to BS 1881:1983. The research
work made use of Scheffe’s (4, 2) lattice polynomial with regression equations to develop mathematical models for the prediction
of the compressive strength characteristics of concretes made with these coarse aggregates. The mathematical model developed
was Ŷ = 30 x1+ 32 x2+ 19 x3+ 12 x4+ 2.8 x1 x2 - 0.8 x1 x3 - 5.6x1 x4 - 2.8 x2 x3 - 8 x2 x4+ 12 x3 x4. The student’s t-test and the Fisher
test were used to test the adequacy of this model. The strengths predicted by the model were in complete agreement with the
experimentally obtained values and the null hypothesis was satisfied.