Autonomous self-healing behavior of geopolymer pastes under varied curing environments
Meral Yıldırım Özen, Rafia Firdous, C.W. Lehmann, Dietmar Stephan
Abstract
This study examined the effectiveness of incorporating self-healing capsules based on sodium silicate in geopolymers containing fly ash and metakaolin. To evaluate the self-healing capabilities, geopolymer samples with the self-healing capsules were preloaded and subjected to different healing conditions: 100% relative humidity at room temperature, 100% relative humidity at 60°C, and water curing. The crack sealing capability, compressive strength recovery, and changes in the sorptivity coefficient of the geopolymer paste with varying amounts of self-healing capsules were investigated. The self-healing process performed under 100%RH-60°C resulted in the highest crack sealing efficiency (91.6±18.53%), mechanical recovery, and improved water tightness. XRD, FT-IR, and SEM-EDX techniques confirmed that primary self-healing products were amorphous aluminosilicates.