CVE1281 Summary & Reader Response (Self-healing Concrete) Draft #4
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 home-owners” 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. 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 about the possibility of the self-healing concrete winning over the construction industry by mentioning the characteristics of self-healing concrete. However, it does not presume a major change in the industry as there is insufficient information to convince the construction industry to adopt the innovation.
Firstly, this article is to define bacterial concrete, its classification and types, mechanism adopted , advantages, disadvantages and its application in the filed of construction by literature view. Dinesh stated that bacterial concrete is eco-friendly to be used and able to self heal the cracks in the structure. He provides rich in information for the study of bacteria on self-healing concrete and it is well supported by experiments results. However, he does not talk about the possibility of it winning over the construction industry by giving actual examples or statistics. Therefore, it is hard to to convince the industry to adopt with the innovation due to the limitation of applications that he mentioned in his article.
Secondly, in this article Haoliang covers the different mechanism of self healing and categorizes concrete structure according to serving condition. He highlights self-healing based on adhesive agents, bacteria, mineral admixtures and autogenours are the four categories of mechanisms. He explains the two methods in detail for both encapsulation and vascular systems techniques. He even concludes with reinforced concrete structure by serving conditions and potentially applied self-healing mechanisms. He provides rich information for its characteristics for readers better understanding of self-healing concrete but he does not talk about the possibility of it winning over the construction industry neither convince the construction industry to adopt the innovation.
Thirdly, this article is to analyse the costs for the biological self-healing in concrete and evaluates the industrial challenges it faces. Silva provides detailed information in comparison of normal concrete and self-healing concrete. He points out the problem of normal concrete and also the path of self-concrete that is undergo. He mentions that self-concrete is under study since 1970 but only attracts attention from 2001 by the article White et al. There are two key points that he highlights the contractors are not responsible for warranty after 10 years in the industry scale whereas applied concrete should have at least of 50 years of service life. He also highlights there are structures need immediate repair once cracks appear, self-healing concrete would be the better choice as it provides guaranties for instant small cracks repair, he gives example such as underground museum to support his statement. Overall, his journal provides better understanding of self-healing concrete. However, from the two tables in comparing the cost of the two concrete, he concludes that it is too expensive for the industry to accept it with a price above €15 to €20 per m3 than the normal market. Which means it is not practical for the self-healing concrete to win over the construction industry any soon.
In conclusion, despite the short-comings and high cost of self-healing concrete. The construction industry has no confident to implement it as it is under investigation stage. With the fact that it is not commonly been used in the construction industry and it is hard for them to take risk and wait for long term gain from maintenance cost. In other words, characteristics of self-healing concrete is yet to finalise, it is not ready to convince the construction industry to adopt with the innovation.
Reference :
Dinesh.S, Shanmugapriyan.R & Namitha Sheen.S.T (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
Haoliang H. (2014, nd). A Review On Self-healing In Reinforced Concrete Structures In View of Serving Conditions. Citeseerx.
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.847.6335&rep=rep1&type=pdf
Silvia. F.B (2015, January). (PDF) Industrial Application of Biological Self-healing Concrete: Challenges and Economical Feasibility. Researchgate.
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
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