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”. Decaux mentioned that roads are mainly made of asphalt, which is a costly material and encourages the formation of "heat islands during heat waves in cities". Developments have been done to create more sustainable materials which will reduce wastage and improve on the quality of roads. Materials such as "recycled plastic" helps to make roads more resilient, while cigarette butts mix with asphalt reduces the "heat island" formation. The author found that other developments include using solar panels on roads to harvest energy, using it to heat up roads during winter and lighting up the roads in the night via motion sensors. Improving on road user’s safety, and the usability of roads.
While there exist greener materials to be
used in replacement of asphalt as Decaux mentioned, it is not a comprehensive
comparison. The author lists the disadvantages of using asphalt, comparing that
against the advantages of using the greener materials. Instead, he should have
also listed the advantages of using asphalt and disadvantages of its
replacement material.
Asphalt, being the current bulk material
for road building, also has its upsides. Firstly, asphalt can be recycled and
is one of the “most recycled material in the world”. It begins when pavements
have broken down and as such has been “reprocessed” into the form known as
“Reclaimed Asphalt Pavement (RAP)”. The main use of RAP is to be added back
into the mixture that makes roadway structures. This has many benefits, such as
improving the strength of new roads. In the online research publication “User Guidelines
for Waste and Byproduct Materials in Pavement Construction”, 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 which is cost-efficient as asphalt is a
“petroleum-based material” so its cost will grow as the petroleum prices rise.
Furthermore, this addition of RAP will lessen the need for mining,
manufacturing and transporting of raw asphalt to be processed which are known
to be expensive tasks, with the added benefit of easing carbon emissions. In
the blog post “How to Recycle Asphalt”, Bennett (2015) talks about the
decreased necessity for new raw asphalt and the huge “environmental impacts”
caused by the shipping.
In the blog, Decaux (2017) mentioned one of
the replacement materials being plastic. Using plastic in road-making helps by reducing
Earth’s plastic wastes but there are also problems associated in this process.
Firstly, not all plastic can be used. There are currently many forms of
plastic, and with that, the melting point of each type of plastic differs.
Bitumen, used in mixtures for road-making, is heated to “150 – 177 Degree
Celsius” in the process. According to Polymer Handbook (4th edition)
(1999;2005), most plastic (polymers) melts at a higher temperature than the
heating of bitumen which means they are non-integrable in road-making.
In conclusion, recycling asphalt has
advantages that are comparable to the advantages of adding plastic in
road-making. Quoting Joel (2008), basically “Recycled asphalt provides a better
product at a lower cost!”. Plastic, on the other hand, have the disadvantage of
issues with integration, which results in non-integrable plastics still being
wasted. As such, I believe that it may still take some time before greener
materials may be 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:
Bennett, S. (2015, June 17). How to Recycle
Asphalt. Recycle Nation.
Retrieved from
Brandrup, J. Immergut, Edmund H. Grulke, Eric A. Abe, Akihiro
Bloch, Daniel R.. (1999; 2005). Polymer Handbook (4th Edition). John
Wiley & Sons.
Retrieved from
https://app.knovel.com/hotlink/toc/id:kpPHE00026/polymer-handbook-4th/polymer-handbook-4th
https://app.knovel.com/hotlink/toc/id:kpPHE00026/polymer-handbook-4th/polymer-handbook-4th
Gopal Mishra. (2018, March 24). Steps in Bituminous
Road Construction. The Constructor.
Retrieved from
Harrington, J. (2005). Recycled Roadways. U.S.
Department of Transportation Federal Highway Administration.
Retrieved from
Joel. (2008, September 17). What is Asphalt Recycling? Pavement
Recyclers.
Retrieved from
McCartney, T. (n.d.). Do
microplastics from the road get washed off into the environment? MacRebur Limited.
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