Summary_reader response draft #2

In the MIT technology review, “What Happened to green concrete?”, Majcher (2015) stated that the intention for producing concrete that absorbs carbon dioxide was to reduce the 5 percent of global carbon dioxide emissions which concrete accounted for. However; due to lack of support, the idea did not make progress, instead, the author introduced other technologies such as nanoengineering and fly-ash. The author mentioned that in 2010, Novacem, a green cement company, found a way to substitute Portland cement with magnesium oxide material that captures carbon dioxide when mixed with water. However, due to a lack of support, it resulted in their eventual liquidation. The author also mentioned, “Storing carbon dioxide in cement is not the only way to improve the material’s environmental footprint.” For instance; MIT’s Concrete Sustainability Hub showed that concretes created from nanoengineering procedure were twice as resistant to breaking and allow lesser concrete used for building constructions. Another way was modifying the properties of concrete by mixing with fly-ash.

The ideal way is to have zero carbon emission from concrete usage. However, green concrete does not garner enough support from researches. I believe the writer should explain the researches on green concrete made by scientists to show why green concrete is not feasible.

The scientist has researched how to create green concrete from nanoengineering by adding graphene into cement. Thus making concretes stronger and use lesser cement. However, the author did not mention the risks and cost of making green concrete with nanoengineering. Kate B. (2018) included in her article by Dr. Rackel San Nicolas, a civil engineer at the University of Melbourne in Australia and an expert on advanced construction materials, that more research must be conducted to determine whether "tiny graphene particles would pose any health or environmental risks." This shows that the constructions are not ready for sustainable concrete at the moment.

Majcher (2015) however did not mention the disadvantages of producing green concrete. An article from krazytech.com, Ravi (2014) mentioned that the main disadvantage of using green concrete is that it is not suitable to be used for constructing bridges or dams as it has less life than portland concretes. If green concretes are to be used for bridges, or dams, special air-entraining agents will be mixed in it which therefore increase the overall cost. This explains why most green concrete was used on a small scale and also lacking support.

Ravi (2014) also mentioned in his limitation of green concrete that "the split tensile strength of the green concrete is less than the conventional concrete. Thus more reinforcements are needed, which increases the construction cost of the structure", this shows that green concrete will not be as strong which means it will be costly to enhance green concrete to meet the construction requirements.

The author concluded that although green concrete was not successful, the takeaway was that cement factories and processes helped to enhance industry energy efficiency by 40% since the 1970s, helping in reducing global carbon dioxide emission.

References:

Kate, B. (2018).  'Green' concrete could be game-changer for construction industry
Retrieved May 03, 2018 from 'Green' concrete could be game-changer for construction industry

Majcher, K. (2015). What Happened to Green Concrete?

Retrieved March 19, 2015 from What Happened to Green Concrete? - MIT Technology Review

Ravi, B. (2014). Green Concrete
Retrieved September 08, 2014 from Green Concrete - Krazytech