CONSTITUTIVE MODELS FOR HEALING OF MATERIALS WITH APPLICATION TO COMPACTION OF CRUSHED ROCK-SALT

Certain materials exhibit a capability to heal with time. Healing impl ies that microcracks and microvoids reduce in size, with a correspondi ng increase in stiffness and strength, features that are exactly the o pposite of those normally associated with continuum damage mechanics. A continuum healing mechanics model is proposed within a framework tha t automatically meets the restrictions of thermodynamics. Rate-indepen dent and rate-dependent formulations are both given. Specific evolutio n equations are given for a scalar isotropic assumption and comparison s with a limited amount of experimental data on crushed rock salt are given. Good correlations are shown for changes in time of Young's modu lus and inelastic strain. The preliminary results provide a good found ation for other examples of healing such as the curing of concrete, th e sintering of ceramics and the compaction of cohesive sands and clays .