ABSTRACT
Due to the advantages of protection and controllable releasing of chemical materials, microcapsules have been widely used to self-heal cementitious materials. However, their applications in granular materials like soils remains to be unexplored. An initial challenge to tackle is the microcapsules retention in open porous media. From laboratory results, a distinctive demarcation between effective and ineffective gravel-microcapsules mixtures was identified in considering the washout of microcapsules. An attempt has been made to develop a design criterion in terms of the relationship of d85 (a representative size of microcapsules being protected) and D15 (a representative size of gravel), following the approach from filter design. The criterion can be adopted for both gravels and microcapsules with different particle sizes and gradations.
