Summary Reader Response Draft #1

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 will improve on the short-coming of the concrete.

Firstly, silica powder, bacteria, and sodium chloride were used to improve the properties of self-healing concrete. Based on the article, “Improvement Properties of Self-Healing Concrete by Using Bacteria.” IOP Publishing (2019), it was stated that silica powder, bacteria (Bacillus Subtilis) and sodium chloride was 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 on its properties of self-healing.

Secondly, 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” Materials (2019). It was said that rubber particles obtained from scrap rubber tires were incorporated into concrete to decrease its brittleness. This will in return cause a smaller crack width as compared to normal concrete. Additionally, the rubber particles have a rough surface and high porosity which makes them an appealing bacteria-carrier contender. It was concluded that the use of rubber particles is a promising method for bacteria carriers in self-healing concrete although there were some problems in the results.

Lastly, according to the article, “The contribution of encapsulated polyurethane adhesive in improving the static torsional resistance of the self-healing concrete beam comparing bonded FRP technique” ScienceDirect (2018), it was stated that adding encapsulated polyurethane adhesive into self-healing concrete can have positive results on the resistance of concrete. Beams were used as test experiments for the test of resistance after adding the adhesive. It was concluded that using self-healing concrete with encapsulated polyurethane adhesive could be an efficient and promising approach when dealing with concrete cracking.

Although the article mentioned briefly the advantages and disadvantages of self-healing concrete, it did not mention how the researchers plan to improve on its disadvantages. There are many ways in which self-healing concrete can be improved on and I believe these are the deciding factor which can win over the risk-averse construction industry.

References

Spinks, R. (2015, June 20). The self-healing concrete that can fix its own cracks. The Guardian. https://www.theguardian.com/sustainable-business/2015/jun/29/the-self-healing-concrete-that-can-fix-its-own-cracks

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.

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