Design and characterization of solid waste based self-healing artificial aggregate

A novel type of solid waste based artificial aggregate which holds promise for a good synergy between mechanical properties and self-healing capacity is designed with using the core-shell structure concept. The artificial aggregate is designed with a high self-healing potential core and a high strength shell, to achieve the high-performance application of artificial aggregates in concrete. The basic properties and potential self-healing capacity of artificial aggregates were comprehensively analyzed. The results indicated that the artificial aggregates were eligible considering the 28-d single particle compressive strength of exceeding 5.0 MPa, low water absorption and high volumetric stability. The crack-healing ratio of artificial aggregate is up to 94.5 % after 7-d curing in the simulated concrete pore solution (i.e., saturated Ca(OH)2 solution). The primary self-healing product was detected as calcium-aluminate-silicate-hydrate (C-A-S-H) gel due to the secondary hydration reactions of core materials.