Sunday, 6 October 2019

Draft #2: Summary Reader Response: New paths for the roads of tomorrow


In the blog post “New paths for the roads of tomorrow”, Decaux (2017) observed that developments in smart infrastructure can be applied to roads, which will further improve roads to be more “smart, connected and safer”. The author mentioned that roads are made of asphalt, which is a costly material and encourages the formation of "heat islands during heat waves in cities". Additionally, he also stated that there had been developments to create greener materials which would improve the quality of roads. Such materials include: "recycled plastic" that helps to make roads more resilient and cigarette butts which are mixed with asphalt that reduces the "heat island" formation. Decaux also found that having solar panels on top of roads could harvest energy. He noted that usage of such energy generated could heat up roads during winter or lighting up the roads in the night via motion sensors, thus improving on road safety and conserving energy similar to how a “smart city” would be.

While there exist greener materials to be used in replacement of asphalt as the author had mentioned, it is not a comprehensive comparison. Comparing both materials, asphalt could still be the better material to use as it has benefits such as being recyclable and as such, reducing cost in the long term, while using plastic waste could be a liability as only certain types could be utilized.

Firstly, asphalt is one of the “most recycled material in the world”. According to a publication by Federal Highway Administration (2005), the majority of all asphalt is recycled back into “highway use”. From another publication by Federal Highway Administration (2008), the process begins when pavements have broken down and are “reprocessed” into the form known as “Reclaimed Asphalt Pavement (RAP)”. RAP is then added back into the mixture that makes roadway structures. This also has many benefits, such as improving the strength of new roads. In that same publication, the Federal Highway Administration (2008) states that when RAP is added to the foundation mixture, it makes the resulting roads stronger over a period of time.

Another benefit of recycling asphalt is that it is a penny-wise process. Adding recycled asphalt into mixtures reduces the amount of raw asphalt needed in new mixes. In the blog post, Patterson (2015) states that RAP reduces the tax from “American taxpayer by $1.8 billion per year”. Furthermore, as lesser raw asphalt would be required, this would also lessen the need for mining, manufacturing and transporting of raw asphalt which are known to be expensive tasks, with the added benefit of easing carbon emissions. In another blog post, Patterson (2015) states that recycled asphalt has “cost lower than traditional asphalt as processes are eliminated”. Also, he mentioned a notable decrease of “greenhouse gas emissions” due to avoidance of gas usage needed in obtaining raw asphalt.

It is true that using plastic waste in road-making helps reduce the total amount of plastic wastes, but only selected types of plastic could be used. As there are many forms of plastic, the melting point of each type of plastic differs. This is important to note as the integration of plastic waste to road-making mixtures requires the process of melting. According to Polymer Handbook (4th edition) (1999;2005), most plastic (polymers) melts at a temperature above 200 Degree Celsius. In comparison, this is higher than the heating of bitumen that is used in mixtures for road-making. According to Mishra (2018), Bitumen is heated to “150 – 177 Degree Celsius” in the process of mixing. Another contributing factor is that some plastics, when heated to its melting point, would produce toxic fumes. According to the UN Environment (2019), plastic incineration creates harmful fumes that are a hazard not just to human, but also plantations and wildlife.

In summary, using asphalt and its recycled counterpart has advantages that are comparable to adding plastic waste in road-making. Quoting Joel (2008), basically “Recycled asphalt provides a better product at a lower cost!”. On the other hand, plastic has issues with integration, which results in non-integrable plastics still being wasted. Thus, it would probably still take some time before greener materials, such as using plastic waste, are able to replace asphalt in the road-making world.


Original blog post:

Decaux, J. C. (2017, October 23). Mobility & Trends; New paths for the roads of tomorrow 
Retrieved from


References:

Brandrup, J. Immergut, Edmund H. Grulke, Eric A. Abe, Akihiro Bloch, Daniel R.. (1999; 2005). Polymer Handbook (4th Edition). John Wiley & Sons.

Mishra, G. (2018, March 24). Steps in Bituminous Road Construction. The Constructor.
Retrieved from

Harrington, J. (2005). Recycled Roadways. (Publication Number: FHWA-HRT-05-003) U.S. Department of Transportation Federal Highway Administration.
Retrieved from

Joel. (2008, September 17). What is Asphalt Recycling? Pavement Recyclers. [Blog Post]
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Patterson, D. (2015, November 04). 5 Benefits of Recycled Asphalt Pavement. Basic Constriction.  [Blog Post]
Retrieved from

Patterson, D. (2015, November 30). Does Sustainable Asphalt Exist? Basic Constriction. [Blog Post]
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Turner-Fairbank Highway Research Center (2008). Reclaimed Asphalt Pavement.  User Guidelines for Waste and Byproduct Materials in Pavement Construction. (Publication Number: FHWA-RD-97-148) U.S. Department of Transportation Federal Highway Administration.
Retrieved from 

UN Environment. (2019, May 02). Plastic bag bans can help reduce toxic fumes.
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