Rheological behaviour and mechanical properties of porcelain stoneware bodies containing Italian clay added with bentonites

This paper presents the results obtained by replacing German and Ukrainian clays in a porcelain stoneware body with a clay from Sardinia island, Italy, added with 10 wt% of different bentonites available on Italian territory in order to lower the body costs. Two series of bodies were prepared: a first series by substituting completely German clay and partially Ukrainian clay (5 wt%) and a second series by substituting completely the Ukraine clay. Rheological measures were carried out on the suspensions prepared in order to verify the effect of the bentonites presence on the shear and time dependence. The fired specimens were characterized across the technological parameters (water absorption, linear shrinkage, etc.), mechanical and aesthetical properties and compared with a standard/industrial composition.