Improvement of Strength on Local Pottery Clays by Traditional Ageing of Clays

The effect of ageing on various parameters such as particle size distribution, specific surface area, dry strength, shrinkage, fired strength, bulk density, and moisture content of clay was stud-ied. The results indicate that ageing introduces finer particle sizes due to a progressive increase in the proportion of the fine particles as the system is aged, the critical moisture content of the aged clays are higher than the unaged clays and the strength of all the aged clays tested showed improvement in strength characteristics than the unaged clays. Ageing affects the bulk density of local clays as the inherent porosity is replaced by fine particles that are produced as the clays are aged. Both bulk density and particle size are recognized as powerful indicators of product quality in both manufacturing and strength of the clays.