Ultrasound and mechanical tests combined with ANOVA to evaluate brick quality

Mixtures of clays are often used in the manufacture of bricks, with distinct additives for diverse ends. The firing process, however, determines the final properties of the material. In this work, ultrasound and mechanical tests have been combined with a statistical tool, the analysis of variance (ANOVA), to analyse the mineralogical and physical characteristics of solid bricks manufactured from mixtures of local clays to which small amounts of additives have been included. They were then fired at different temperatures, ranging from 850 up to 1100°C. A new parameter, defined as the “resistance anisotropy” has been formulated to simplify the statistical interpretations. In addition, a two-way ANOVA interaction analysis has been used to evaluate the effect that selected factors (addition/absence of additives and firing temperature) have on the technical quality of bricks.