Abstract
In-ground vertical barriers are one of the most commonly-used contaminated land remediation technologies to prevent the migration of contaminants. Despite the popularity of in-ground barriers, problems related to their durability and mechanical properties impact serviceability, leading to the need for urgent repair. In-ground barrier materials, therefore, need to be more resilient, so that their whole life carbon emissions and whole life costs can be significantly reduced. Self-healing methodologies, including microencapsulated minerals, have been developed over recent years, with the focus on concrete. The mechanism of self-healing microencapsulation system is that when cracks propagate in the matrix, they rupture the capsules, leading to the release of healing agents into the crack volume. In this study, microencapsulated sodium silicate was incorporated in in-ground barrier materials and the mineral reacts with the calcium hydroxide in the cementitious matrix to form the calcium-silicate-hydrate gel. The characterisation of two different microcapsules and their effects on the properties of in-ground barrier materials were presented. Self-healing efficacy of in-ground barrier materials was examined in terms of crack sealing and the recovery of mechanical properties.