How and why do air-dried clays crack?

Vaibhav Raj Singh Parmar and Ranjini Bandyopadhyay*

  *: speaker, ranjini@rri.res.in

Thin layers of aqueous clay suspensions that are exposed to the environment can crack due to the buildup of desiccation-induced stresses. In this work, we show that the crack onset time in a drying clay sample, obtained via imaging, is inversely correlated with the square root of its Young’s modulus, measured in atomic force microscopy microindentation experiments. We explain this scaling by incorporating the Griffith’s fracture theory in the poroelastic model. Our results are important in the preparation of crack-resistant coatings and in the field of art conservation.