Phenomenon of moisture expansion and its influence on mechanical properties of brick clay products

Abstract

The paper considers the moisture expansionphenomenon, as a specific form of corrosion process ofbrick clay products degradation [1]. The influence of themineralogical composition of raw materials, firingtemperature and environmental parameters on themagnitude of the moisture expansion phenomenon andmechanical properties of brick clay products have alsobeen considered. The study of the moisture expansionphenomenon of brick products was done using twotypical raw materials, one with a considerable and theother with a low content of earth-alkaline carbonates.All investigations were carried out at room temperatureon the fired samples, on the fired samples after firingand after hydrothermal treatment and reheating of thesamples at 550°C. It was found that brick moistureexpansion depends on the presence or absence of earthalkalinecarbonates in raw materials, temperature offiring, appearance of amorphous phase as well as on themodulus of elasticity [2]. Brick raw materials with lowcontent of earth alkaline carbonates in the fired stateshow a higher tendency to moisture expansion and firedbrick products with high content of earth alkalinecarbonate show a minor tendency to moisture expansion[3]. The experiments have confirmed the influence ofthe modulus of elasticity on moisture expansionmagnitude. Moisture expansion caused the decrease ofmechanical properties and small increase of the volumeof brick clay products, ranging from 0,001 mm to 0,7mm/m.