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. Novacem, 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 cited 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 project site but was still under development. Solidia Technologies’ green concrete is stronger and crack resistance but had not advance 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 develop their technologies and the benefits they brought in reducing carbon emission, she failed to elaborate what are the underlying factors that hindered the industry players from utilising the technologies.
CeraTech’s technology may has its environmental benefits, but technically the effective cost is lesser in comparison to that of 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 where cost effectiveness is crucial to sustain the business.
The success 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 factors like creep, shrinkage and flexural strength are compromised. Based on the journal “A Review Paper on Green Concrete” by Nikhil, Divyank & Jeeya (2018), it mentioned that “shrinkage and creep are high” while flexural strength decrease. These implicate the application for green concrete is limited as it is not flexible for usage like earthquakes prone areas as well as high deformations will be resulted due to the creep and shrinkage, which means 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 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 nanoengineered 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.
References
http://news.rice.edu/2018/06/18/cementless-fly-ash-binder-makes-concrete-green-2/ Williams (2018) accessed: 1 Feb. 19
http://ijer.in/publication/v7/173.pdf
https://www.nbcnews.com/mach/science/new-green-concrete-could-be-game-changer-construction-industry-ncna870371
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