Quantitative evaluation of crack self-healing in cement-based materials by absorption test

This study investigates the self-healing performance of cement-based materials using the water absorption test. The experimental method was performed in compliance with ASTM C 1585 on paste specimens mixed with research cement (RC), ground granulated blast-furnace slag (GGBS), anhydrite, and calcium sulfo-aluminate (CSA) expansion agents as inorganic binders. The water flow test was also performed for comparison and the self-healing products were analyzed. The results showed that the proposed method using the water absorption test could effectively evaluate the self-healing performance and that the mixture with GGBS and CSA expansion agents displayed the best performance. The temporal variation in water absorption rates was used to analyze the effects of primary self-healing (due to the further hydration of unreacted materials) and secondary self-healing (due to ion diffusion). The analysis provided results similar to those of the water absorption test. A comparison with an experiment on self-healing products confirmed that the amount of generated calcite had a larger effect on self-healing than the total amount of self-healing products.