• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.1
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• pp.112-119
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• 2020

In this study, cellulose-based bacterial pellets was used for the self-healing concrete manufacturing. The pellet is composed of complex cultured bacterial spore powder, methyl cellulose, two kinds of PVA nutrients and water, and is extruded through a hydraulic press to have a shape of 2mm in diameter to 3 to 4mm in length. Cellulose pellets expand at neutral pH, release bacteria and nutrients, and do not react in a basic environment, increasing the long-term survival rate of bacteria in cement mortar. In addition, pellet self-healing performance of pellet mortar was significantly higher than that of control mortar. Cellulose-based pellets are a new type of bacterial carrier system that will help develop self-healing concrete in the future by improving and optimizing pellets.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.4
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• pp.569-576
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• 2022

In this study, the healing performance of hybrid self-healing concrete was investigated by mixing bacterial pellets(BP) and solid phase capsules(SC), respectively, based on organic-inorganic self-healing material(MC). Constant water head permeability test was applied as a method of evaluating the healing performance, and the healing rate and the healed crack width calculated by the equivalent crack width were used as evaluation indicies. As a result of the water permeability test, when the initial crack width was 0.3 mm, the healing rates of MC-BP and MC-SC were 2.1~3.0 %pt higher than that of MC, and the healed crack width of hybrid concrete increased by 0.017~0.018 mm. In conclusion, it was found that the self-healing performance was not significantly improved even if the two types of healing materials are used together.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.221-222
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• 2021

Bacterial self-healing concrete is known to improve the durability of concrete by preventing the propagation of microcracks. In the literature, bacteria prevent the corrosion of rebar by inhibiting water transfer through crack, but also can promote the corrosion by acting as an ion acceptor in the rust generation mechanism. Therefore in this study, the electrochemical analysis of bio-filmed rebar was conducted to explore the effects of the self-healing bacteria on the bare rebar without cement composite. As a result of the experiment contradicting trends for Ecorr and Icorr occurred and additional experiment will be conducted in various environments to collect data on the mechanism of corrosion of rebar by bacteria.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.203-204
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• 2021

Bacteria used in self-healing concrete, which arrest the crack, helps increasing the durability is well known. However, the survival and activity of the bacteria are precisely unknown. In this research, to know the bacteria's survival curve on the surface of the cement composite, bacteria's survival curve has been measured by CFU at different curing days. The survival curve of 3 days and 7 days curing does not show the significant differences in their survival tendency. However, the slope of death phase of 7 days curing was steeper than the 3 days of curing. This research was focused on the death phase but for further research, set of interval time will be reduced and observe the lag phase and exponential phase.