Call for Entries: Roads - The Next Generation Environmental Threat
By Mohitparames Thirumurukan, Class 9, Mahatma Global Gateway, Madurai
There are a numerous number of environmental problems which are common everywhere. But each area has a unique problem. In my area, the main problem are the roads. Now-a-days, roads are made from asphalt, bitumen and gravel. These roads are durable and can last for long time, but they contribute to global warming. This may not make sense initially, but I will explain.
The modern roads are made from asphalt, bitumen and gravel. Asphalt and bitumen absorb a little heat and radiate most of it back, then greenhouse gases radiate the heat back. When compared to dirt and sand roads, asphalt roads absorb barely any heat. But over the years of use sand, dirt and other particles settle into gaps in the asphalt and start to reflect less heat. The increase in heat absorption is only in regular cases where single layer asphalt roads are used for years and years together. I mention single layer because, if there are multiple layers, it actually decreases the heat absorbing capacity of the road. Now you may be wondering how this is possible because if one layer can absorb heat, then multiple layers would absorb more heat. But this is not the case. As asphalt roads absorb very little heat, the absorbed heat by the top layer seeps down, it gets reflected on to the layer below it in pores. This heat gets reflected back by the bottom layer and process repeats again. This also increases the heat intensity. The reflected heat ends-up heating the asphalt so much, that the asphalt also radiates heat. This is why, at times the temperature of a multi layer lower road is hotter than the surrounding temperature. This is also why roads are dug up before being replaced.
In my area the problem is that, the government lay roads on top of the old one, covering everything, including manholes. When the drainage gets clogged, people end-up making a hole above the manhole, to unclog the drainage. As it rains frequently, the water seeps into the layers of asphalt and erodes it. When pressure is applied on the eroded areas, the area sinks and forms potholes. So, to fix this, the government lays a road again. Because of this, the roads don’t last more than 8 months. This layering also increases global warming. Because of the frequent need to lay roads, more asphalts and bitumen are required, both of which are petroleum by products obtained from crude oil. This increase need of fossil fuels also increases pollution. The solution which propose is simple and easy. What I think should be done is that, the existing layer of roads should be removed and single layer must be laid to the level of manholes. This will block the paths for water to seep and erode the asphalt. I also recommend to use waste plastics in road construction. This may be a simple and straight forwards solution, but it will reduce global warming and pollution by a small, but significant amount.