Modelling the self-healing potential of dissoluble encapsulated cement

In its fresh state, cementitious systems can be considered as colloidal suspensions build up from a mineral particles that follow a predefined grading. In this paper, a modelling approach that shows the healing potential of a blended cementitious system will be provided that consists of original cementitious particles mixed with so-called Dissoluble Encapsulated Particles (DEPs). DEPs are represented by a range of predefined fractions of original cementitious particles, but with its surface covered with a thin membrane. The self-healing principle of this system is based on the most basic healing process, where a delayed hydration of the DEP fractions may occur initiated by a crack. The crack actually triggers the membrane to open and exposes the still unhydrated DEP particles to water, after which the delayed hydration of the DEP system will take place, while closing the crack. The proposed model will demonstrate the healing potential of DEP inside a concrete and analyse the most dominant parameters affecting the mechanism. The membrane is considered to decapsulate by it's dissolution or cracking whenever being triggered by cementitious crack formation, which either lowers pH-conditions due increased CO2 ingress, or induces mechanical stresses. The results show the potential of the healing mechanism to bridge a certain crack width, and shows, which fractions of a regular cement should be replaced in order the DEP system being most efficient. The numerical predictions also show that multi fraction DEP systems are more efficient then single fraction DEP, and that the addition of DEP does not affect the properties but may lead to a delay in the property development of cementitious systems.