Self-healing concrete incorporating mineral additives and encapsulated lightweight aggregates: Preparation and application

摘要

Incorporating minerals and lightweight aggregates with built-in carbonates can promote the self-healing efficiency of concrete. Appropriate encapsulation of lightweight aggregates is required to avoid premature carbonate loss before cracking. In this study, lightweight aggregates were encapsulated using epoxy resin. In addition to characterizing the structure and encapsulating performance of encapsulated lightweight aggregates, the effects of minerals and encapsulated lightweight aggregates on the fresh, hardened, and self-healing properties of cracked concrete and healing products were investigated; CaCO3 was determined to be the main healing product. The results showed that the encapsulated lightweight aggregates improved the mechanical properties and retention ability of carbonate. For a concrete comprising mineral additive and encapsulated lightweight aggregates, while the slump value and setting time decreased, the strength and chloride migration resistance increased. The normalized healing efficiency of crack areas and the resistance and capacitance, obtained from electrochemical impedance spectroscopy analysis, revealed improved healing efficiency by incorporating the minerals and encapsulated lightweight aggregates, reached 45.69%, 48.71% and 85.33%, respectively. Due to the encapsulation property, the self-healing ability of the mixture under long-term effects is worth studying in the future.