Self-Healing Concrete Summary + Reader Response Draft 4

In the article, “The Self-healing Concrete That Can Fix Its Own Cracks”, Spinks (2015) described 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 would 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 costs €70, while the self-healing concrete costs €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 Spinks gave some information about the self-healing concrete, he should also have mentioned the viability such as, high-cost limitations, how water and air will affect the concrete, how the bacteria would affect the mechanical properties of concrete, and also if there is an Indian Standard Code as it is a safety guideline for constructions.

Firstly, 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 according to Pal (2019), this becomes 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 is dependent on the existence of air and water. According to Pal, D. (2019) and Shanmuga, R. (2016), being dependant on air and water helps reduce the permeability of the concrete, improves the durability of steel reinforced concrete, and also reduces corrosion of steel. When the self-healing agents activates due to contact with air and water, it causes certain reactions within the cement to form. This causes 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 which in turn strengthen the durability of the steel. This makes it viable to be used in construction 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. According to Build Abroad (2017) and Silva et al., (2016), the cost of self-healing concrete limits the use to only at areas where water leakage or corrosion of steel are serious due to the high cost. 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 is due to the materials used and it may be resolved if it could be “tweaked with a sugar-based nutrient”.  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 crack and has a long lifespan, it also improves the compressive strength of the cement, which enables it to become stronger. According to Hitendra et al., (2018), various tests were done on the 7^th day and the 28^th day on the self-healing concrete. The result of the test shows a value greater than conventional concrete.

Although Spinks gave some information on self-healing concrete, more detailed information on how the viability of the concrete should be elaborated. Having more detailed information would allow countries to understand if the product could be used for their constructions.

References:

Build Abroad (2017, January 17). This is crazy! Self healing concrete is a material you have to see to believe.

https://buildabroad.org/2017/01/17/self-healing-concrete/.

 

Hitendra, S., & Vijay, S., & Satyendra, D. (2018, October). Study of compressive strength of self-healing concrete. Irjet. 

https://www.irjet.net/archives/V5/i10/IRJET-V5I10217.pdf

 

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/.

Shanmuga, R.(2016, December). A review on bacteria-based self-healing concrete. Imperial Journal of Interdisciplinary Research (IJIR), 3(1), 1023-1026.

 

https://www.researchgate.net/publication/311970887_A_Review_on_Bacteria_-Based_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. Journal of Commercial Biotechnology, 21(1), 31-38.

https://www.researchgate.net/publication/270586240_Industrial_Application_of_Biological_Self-healing_Concrete_Challenges_and_Economical_Feasibility.

Spinks, R. (2015, June 29). 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

 

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