Summary_reader response Draft #2

In the article "What Happened to Green Concrete?", Majcher (2015) stated that albeit the existence of green concrete and its benefits, the application was not common as it failed to garner support from the industry. The technology also did not advance over the years. She cited Novacem, the forefront of green cement in 2010, winded up in 2012 due to poor investment for its green concrete technology. While Calera another company, changed its focus to commercialise its green concrete technology with fibre to make boards for toilet usage; a more lucrative process.

Majcher mentioned that CarbonCure, on the other hand, sells green cement that had been utilised by approximately 20 projects in the 2 years since it had started. The technology only helped decrease carbon footprint by 5% but more if the carbon used was captured by the plant itself. The production cannot be in situ at the project site but was still under development. Solidia Technologies' green concrete is stronger and crack resistance but had not advanced since 2008 even with supports from big companies like Lafarge. 

She also mentioned how Nanoengineering and inclusion of fly ash also can help to reduce "material environmental footprint". MIT's Concrete Sustainability Hub published in 2014 that nanoengineered concrete can resist fracturing better and cement usage is reduced. Meanwhile, CeraTech found that replacing Portland cement with 95% fly ash not only reduced carbon emission (since it cures under chemical reaction) and water by half, landfill usage can be reduced.

While Majcher listed how the various companies developed their technologies and the benefits they brought in reducing carbon emission, she failed to elaborate on what are the underlying factors that hindered the industry players from utilising the technologies.

CeraTech’s technology may have its environmental benefits, but technically the effective cost is lesser in comparison to cement. In the article "Cementless fly ash binder makes concrete ‘green’”, Williams (2018) quoted Shahsavari, "an assistant professor of civil and environmental engineering and of materials science and nanoengineering", that "environmental benefits" are neutralised with the requirement for costly "sodium-based activators" for substituting Portland cement with fly ash. This may further explain the hindrance for the construction industry to utilise green concrete, as like all sectors cost-effectiveness is crucial in sustaining the business.

The successful application of green concrete in the industry will also be dependent on the technical benefits it brings about. Majcher listed down some of the technologies can help with strengthening, longer lasting and fracture resistance. However, she neglected other compromised factors like creep, shrinkage and flexural strength. Based on the journal “A Review Paper on Green Concrete” by Nikhil, Divyank and Jeeya (2018), it mentioned that green concretes’ “shrinkage and creep are high” while flexural strength decreases. These suggest the application for green concrete is limited as it is not flexible for usage like earthquakes prone areas. High deformations will also be resulted due to the creep and shrinkage, meaning the application is restricted to less intensive load situation. This is one of the reasons why the industry is hesitant to utilise the technologies.

In Majcher’s article, nanoengineered green concrete was reported to reduce cement usage. However, in the article "'Green' concrete could be game-changer for the construction industry" by Baggaley (2018), she quoted Dr Franz-Josef Ulm, "faculty director of the Concrete Sustainability Hub at MIT", where he had reservation for graphene (a nano-engineered material) due to its cost citing ‘it was more of a "concept material"'. Meanwhile, Dr Rackel San Nicolas, “a civil engineer at the University of Melbourne in Australia and an expert on advanced construction materials”, research is still on to rule if there are “any health or environmental risks” resulted from the tiny graphene particles. These explained the reasons more effectively why the industry is more resistant to switching to green concrete technologies.

In conclusion, factors like cost-effectiveness, technical lapse and potential health or environment risks hampered the utilisation of green concrete by the construction industry as opposed to Majcher's citation of the benefits the green concrete bring.  

References

Baggaley, K. (3 May, 2018). 'Green' concrete could be game-changer for construction industry. Retrieved 1 February, 2019, from https://www.nbcnews.com/mach/science/new-green-concrete-could-be-game-changer-construction-industry-ncna870371

Nikhi, C., Divyank, J., & Jeeya, R. (2018). A Review Paper on Green Concrete. International Journal of Engineering Research, 7(Special 4), 563-565. Retrieved from http://ijer.in/publication/v7/173.pdf

Williams, M. (18 June, 2018). Cementless fly ash binder makes concrete ‘green’. Retrieved 1 February, 2019, from http://news.rice.edu/2018/06/18/cementless-fly-ash-binder-makes-concrete-green-2/