Self crack healing of strain hardening cementitious composite incorporating expansive agent and crystalline additive

This research studies the self-healing potential of strain hardening cementitious composites (SHCC) incorporating crystalline additive (CA) and calcium sulfo-aluminate based expansive additive (CSA). A four point bending set-up was used to pre-crack the SHCC specimens at the age of 28 days. Thereafter, the specimens were submerged in water for 28 days to create a self-healing process. The experimental results indicated that the SHCC specimens with CSA and CA showed a superior surface crack closing ability. The precipitation of calcium carbonation can be observed on the surface crack of the specimens. Eventually, the healed specimens were bent until failure to evaluate the possibility of mechanical recovery. The specimens submerged in water showed a significant improvement of mechanical recovery compared to those air-cured specimens which were used as references. After the self-healing process, the deflection capacity can recover about 60-150% compared to the original specimens. The mechanical recovery was in the order of M1 (Control) < M3 (CA) < M2 (CSA) < M4 (CA + CSA).