Correlation between Bigot and Ratzenberger drying sensitivity indices of red clay from Ratchaburi province (Thailand)

The aim of this work is to study the drying sensitivity of red clay bodies from Ratchaburi province (Thailand) by determining Drying Sensitivity Index—Bigot (DSI-B) and Drying Sensitivity Index—Ratzenberger (DSI-R) of 11 clay mixtures with different amounts of additives (sand, grog and pottery stone). The results revealed that the drying sensitivity values of the clay mixtures obtained from both methods decreased with increasing amount of additives. The relation between DSI-B and DSI-R was relatively good in linearity and the correlation coefficient was 0.92. Hence, the improvement in drying properties of the clay body by the addition of non-plastic additives can be quantified by either method since the results are correlated.