Hung, V.V. (author), Kishi, T. (author), Ahn, T.H. (author), Hung, V.V. (author), Kishi, T. (author), and Ahn, T.H. (author)
Granulation technique, introducing the self-healing ability to concrete, was developed by Koide, 2010 [1] based on the capsulation technology in the food/medicine industry. In this research, self-healing granules, containing cement compounds, chemical and mineral admixtures, were fabricated by a proposed granulation process and the capability of crack-self healing concretes incorporating granules was investigated. Self-healing granules, which were manufactured in advance by a roller mixer in the laboratory, were added to the concrete mixture as partial sand replacement, at a dosage of 70 kg/m3 concrete. In order to examine the self-healing performance of the concrete, a water passing test, in which a constant water head of eight centimeters flowing through a static crack of 0.2-0.4mm in width, was conducted for two months. Three different regimes of cured conditions i.e regime one (cured in water at 40oC for one month-short term range), regime two (cured in air at 20oC, relative humidity of 60% for twelve monthslong term range) and regime three (cured in water at 40oC for nine months and then in air at 20oC, relative humidity of 60% for three months-long term range) were applied to investigate the self-healing capacity of concrete. In this study, the capability of crack self-healing concrete was assessed by observating the reduction of water leakage over time, the closing process of surface crack and chemical analysis of deposit products in the crack. Based on the experimental results, the performance of self-healing concrete, improved by selecting the ingredients of granule and developing suitable method for granulation, will be discussed.