Summary Reader Response Draft #3 (Submission)
In
the article, “The Self-Healing Concrete That Can Fix Its Own Cracks,” Spinks
(2015) stated that Hendrik Jonkers created self-healing concrete innovation to
“decrease the amount of new concrete produced, lower maintenance and repair
costs for city officials, building owners and homeowners” by inlaying
self-activating limestone-producing bacteria into the concrete. The
self-healing concrete has a longevity of up to 200 years and helps to reduce
carbon emitters. However, the concrete can only repair up to 0.8mm wide of
cracks and cost €30 per metre cube more than normal concrete. According
to Alker, who is director of policy at the UK Green Building Council believes
that it will be hard to convince the industry to adopt the new innovation. It
will take unconventional consumers and developers who are willing to test their
building with the new concrete to demonstrate positive results before others
will support it. Jonker has also been experimenting across the world where he
claims that the people realized the profit because they can save from
maintenance cost.
The
article discussed the advantages and disadvantages of self-healing concrete but
failed to mention how the researchers can improve on the short-coming of it
which are the hefty cost, limited healing ability and limited durability.
The
first point is overcoming the hefty cost of the self-healing concrete. According
to Li (2012), he stated that the current cost cycle of normal concrete has a high
cumulative cost over time due to additional cost and maintenance fees. However, in comparison, the self-healing
concrete may have a high initial cost, but its healing ability ensures the quality of the
infrastructure with minimum or no additional cost added to the cost cycle. This
suggests that the cost cycle of self-healing concrete and normal concrete are
competitive. The total cost cycle of both concrete may be very similar in the
long run. The best way of overcoming the hefty cost of self-healing concrete is
to educate consumers and developers to look at the benefits instead of focusing
on the initial cost.
The next point is improving the limited healing ability
of self-healing concrete. Self-healing
concrete should ideally have a “highly porous structure as it can provide
oxygen, water and growth space to bacteria after concrete cracks”. In an
article titled, “Self-Healing Concrete Using Rubber Particle to Immobilize
Bacteria Spores” Xu (2019), it was said that rubber particles obtained from
scrap rubber tires were incorporated into concrete to decrease its brittleness.
This will result in a smaller crack width as compared to normal concrete. As the
current innovation only repairs up to 0.8mm of cracks. By decreasing the crack
width when concrete is damaged, the self-healing concrete would be able to repair
the crack within its ability.
Lastly,
to increase the durability, silica powder, bacteria (Bacillus Subtilis), and
sodium chloride was added into the self-healing concrete. Based on the
article, “Improvement Properties of Self-Healing Concrete by Using Bacteria.”
Hussein (2019), it was stated that silica powder, bacteria (Bacillus Subtilis),
and sodium chloride were added to improve the properties of self-healing
concrete. Different concentrations of the bacteria (Bacillus Subtilis) were
added to the concrete mixture before conducting experiments to test for water
absorption and compressive strength. It was noted that there was an increase in
compressive strength and density in the specimen with the bacteria. This shows
that introducing different bacteria into the concrete is the approach done to
improve its durability of the self-healing concrete.
All in all, the article mentioned the advantages and disadvantages of self-healing
concrete however it did not mention how it can be improved on. There are many ways in
which self-healing concrete can be further improved and I believe these are the
deciding factor which can win over the risk-averse construction industry.
References
Anbarlouie, M., Mahdikhani, M., & Maleki, A. (2018, October 16). The contribution of encapsulated Polyurethane adhesive in improving the static TORSIONAL resistances of self-healing concrete beam Comparing BONDED Frp technique. ScienceDirect
https://www.sciencedirect.com/science/article/pii/S0950061818323705
Hussein1, Z. M., Abedali1, A. H., & Ahmead2, A. S. (2019, August 1). Improvement Properties of Self Healing Concrete by Using Bacteria. IOP Conference Series: Materials Science and Engineering.
https://iopscience.iop.org/article/10.1088/1757-899X/584/1/012034/meta.
Li, V. C., & Herbert, E. (2012, June 28). Robust self-healing concrete for sustainable infrastructure.
https://www.jstage.jst.go.jp/article/jact/10/6/10_207/_article/-char/ja/
Spinks,
R. (2015, June 20). The self-healing concrete that can fix its own cracks. The
Guardian.
Xu, H., Lian, J., Gao, M., Fu, D., & Yan, Y. (2019, July 19). Self-Healing Concrete Using Rubber Particles to Immobilize Bacterial Spores. MDPI.
https://www.mdpi.com/1996-1944/12/14/2313
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