C. I. Nwoye^1,, I. E. Nwosu², S. O. Nwakpa¹

The synergic effect of post-fired volume shrinkage and apparent porosity of bricks on its water absorption level during service in submerged state was evaluated. A clay sample was prepared and processed, following a well detailed step-wise route. Analysis of water absorption by the produced bricks while serving under submerged condition was carried out using a two-factorial empirical model expressed as ξ = - 1.0525 ₰ – 2.6392 ϑ + 107.6801. The validity of the derived model was rooted in the core expression ξ – 107.6801 = - 1.0525 ₰ – 2.6392 ϑ where both side of the expression correspondingly approximately equal. Results generated from both experiment and model prediction indicates that water absorption decreases with decreasing apparent porosity and increasing post-fired volume shrinkage. Evaluated results indicated that the correlations between water absorption and post-fired volume shrinkage & apparent porosity and the standard error incurred in predicting water absorption for each value of the post-fired volume shrinkage & apparent porosity considered, as obtained from experiment, derived model and regression model were all > 0.95 as well as 0.0704, 0.0693 and 4.38 x 10-5 & 0.0028, 0.2201 and 2.58 x 10-5 % respectively. The maximum deviation of the model-predicted water absorption (from experimental results) was less than 8%. This translated into over 92% operational confidence for the derived model as well as over 0.92 synergic effective coefficients for the dependence of water absorption level of the submerged bricks on post-fired volume shrinkage & apparent porosity.

synergic effect, post-fired volume shrinkage, apparent porosity, bricks, water absorption, submerged state