Akademik Veri Yönetim Sistemi
7th International Conference on Self-Healing Materials (ICSHM 2019), Yokohama, Japonya, 3 - 06 Haziran 2019, ss.109
Cracks in concrete may act as preferential location for ingress
of aggressive agents, like chlorides, towards the
reinforcement. Precipitation of calcium carbonate by protected bacterial
consortia introduced in self-healing concrete will help to heal
cracks when they appear. However, complete healing of cracks
with a width of several hundreds of micrometres will take a
number of weeks. Therefore, the question rises whether this healing
mechanism allows to avoid corrosion in a chloride containing
environment. Two types of self-protected bacterial granules were
integrated in mortar specimens containing a steel rebar. Granules
containing ureolytic bacteria did provide crack healing, but could not
completely avoid corrosion initiation and propagation.On the other hand,
denitrifying granules provided corrosion inhibition, as was noticed
from measurements of open circuit potential and gravimetric mass loss of
reinforcement bars. The denitrifying granules were able to heal 300 μm
wide cracks in one month time. Furthermore, during exposure to chloride
solution, the obtained performance regarding reinforcement protection
was comparable with that of cracked mortar containing chemical inhibitor
or even uncracked mortar. This is a result of nitrite release by the
denitrifying granules, which quickly stabilizes the corrosion reaction
products and hinders the formation of mobile iron chloride complexes