Effect of firing temperature and mineral composition on the mechanical properties of silty clays

ABSTRACT The physical and mechanical properties of ceramic blocks are affected by the firing process of the primary raw material, in this case, clay or clay minerals. Consequently, this study sought to characterize different types of silty clays for ceramic block production and determine the effect of firing time and mineral content on their mechanical and physical properties. Characterization was conducted in two stages: pre and post-firing. Pre-firing evaluations were granulometric distribution, Attenberg limits, chemical composition, mineral composition and thermal behavior. Post-firing evaluation made use of 30 specimens subjected to temperatures of 800 °C, 900 °C and 1,000 °C. Results showed that firing temperatures greatly affected mechanical properties. Higher burn temperatures increased tensile strength and reduced water absorption while causing linear shrinkage. This increase in shrinkage raised the possibility of damage to the ceramic material and reduction of overall quality.