Self-Healing Concrete Summary + Reader Response Draft 2
In the article, “The Self-healing Concrete That Can Fix Its Own Cracks”, Spinks (2015) narrated an innovation that Jonkers invented which was embedding self-activating bacteria into concrete to make it self-healing. He stated that the bacteria can exist for up to 200 years as long as particles exist for it to feed on, and also mentioned that the bacteria will start producing limestone to repair the cracks when water starts seeping into the cracks. He also noted that the self-healing concrete was unable to repair large cracks, and only capable of repairing cracks up to 0.8mm wide. According to Jonkers, a cubic meter of concrete cost €70, while the self-healing concrete cost €100. Nonetheless, Jonkers remarked that some countries with coastal communities or tropical regions with extreme rainfall are seeing the cost-benefit analysis of using the self-healing concrete. It was concluded by Jonkers that these tests were done in developing countries where they see profits in the future.
While the article gave some information about the self-healing concrete, it should also mention the viability of it being used in construction of buildings.
Firstly, in Civil Engineering, there is an Indian Standard (IS) code that covers every aspect of civil engineering, and this is especially true for construction activities. In order to use the self-healing concrete, there is a need to mix the bacteria along with the concrete, and this comes an issue where mixed concrete with bacteria does not exist within the IS code. Without an IS code, it is harder to get the exact mix for the best performance, and it also means there will be a lack of safety due to the possible weakening in performance. It will be better if the design for mixed concrete with bacteria is included in the IS codes.
Secondly, the self-healing agents act on the existence of air and water. This helps reduce the permeability of the concrete, improves the durability of steel reinforced concrete, and also reduces corrosion of steel. Self-healing concrete caused certain reactions within the cement to form, and this caused the porosity to decrease which in turn reduces the permeability of the cement. With the lack of air and moisture, reinforced steel will not corrode as easily with the lack of oxygen which in turns strengthen the durability of the steel. This makes it viable to be used in constructions as it greatly enhances the structure of the building and reduces the need of maintenance.
Thirdly, the cost of self-healing concrete is relatively high. This is mainly due to one of the elements that is being used in the creation. This high cost limits the use of the self-healing concrete to only at areas where water leakage or corrosion of steel are serious. Although, it can also be used when there is an urgent need to repair cracks such as, a museum, or a library. However, the cost of the self-healing concrete may only be a temporary issue and it can be resolved along with the improving technologies. If the cost of self-healing concrete gets cheaper, it will be a good replacement toward conventional concrete.
Lastly, the bacteria that is being used in the concrete not only repairs cracks and has a long lifespan, it also improves the compressive strength of the cement which enables it to become stronger. In a report, “Study of Compressive Strength Of Self Healing Concrete”, various tests were done on the 7th day and the 28th day on the self-healing concrete. The result of the test shows a value greater than conventional concrete.
To conclude, self-healing concrete is a very viable solution to be used in existing or future buildings as long as the design for mixed concrete with bacteria exists within the IS code, and better technologies to reduce the cost of self-healing concrete.
Spinks, R. (2015, June 29). The self-healing concrete that can fix its own cracks. The Guardian
Pal. D. (2019, July 28) What is Bacterial Concrete or Self-Healing Concrete? Civil Engineering Notes
https://www.civilenggnotes.in/what-is-self-healing-concrete/.
Silva, F & Boon, N & De Belie, N & Verstraete, W. (2015, January). (PDF) Industrial Application of Biological Self-healing Concrete: Challenges and Economical Feasibility. ResearchGate
Shanmuga, R. (2016, December). A Review on Bacteria -Based Self-Healing Concrete. ResearchGate https://www.researchgate.net/publication/311970887_A_Review_on_Bacteria_-Based_Self-Healing_Concrete.
International Research Journal of Engineering and Technology (2018, October). STUDY OF COMPRESSIVE STRENGTH OF SELF HEALING CONCRETE. Irjet.net.
https://www.irjet.net/archives/V5/i10/IRJET-V5I10217.pdf
Build Abroad (2017, January 17). This is crazy! Self healing concrete is a material you have to see to believe. Build Abroad.
https://buildabroad.org/2017/01/17/self-healing-concrete/.
Thank you, Amos, for this well-researched and interesting essay. You have a clear, concise, and appropriate summary. You also present a fairly decent thesis, though you might be able to clarify it further by making the controlling ideas more obvious. I particularly like the details in your body paragraphs, rich with information, but you need to link each of those back to the thesis, which can be done if you alter the thesis. There are other issues in terms of language use and citations conventions that we can review, but content-wise, this is a good effort. Let's talk about this.
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