Shrinkage cracks in clay tile are primarily caused by which of the following factors?

Shrinkage cracks in clay tile are primarily caused by differential drying rates. As clay tiles dry, they lose moisture, which causes them to contract. If parts of the tile dry at different rates, due to variations in thickness, humidity levels, or airflow, it can lead to uneven shrinkage. This uneven shrinkage creates tension within the material, resulting in cracks as the tiles attempt to reach a uniform state.

While differential moisture absorption, excessive heat during firing, and chemical reactions during manufacturing may affect the overall quality and durability of the clay tiles, they are not the primary factors specifically linked to the formation of shrinkage cracks. Instead, the influence of drying rates directly relates to how the material physically changes shape and volume, making it the key factor in this context.