Summary/Reader Response Draft #1: "Porous Asphalt Is King of the Road" (b)

  The article “Porous Asphalt Is King of the Road'' (Pavegreen, n.d.) introduces the features and uses of porous asphalt. It is a type of road surface used to improve safety, diminish water pollution and decrease erosion. The Environmental Protection Agency had identified it as the leading practice for stormwater management. The article states that porous asphalt is made up of rocks glued together with asphalt cements while reducing the fine aggregates used. This allows rainwater to seep through the space between the rocks which decreases the surface runoff. Porous asphalt can be built above a stone recharge bed or a conventional road base. The article mentions that during winter climates porous asphalt requires less anti-icing agents. This reduces the amount of chloride from the agents which is toxic to aquatic life in the runoff. In highways the porous surface absorbs rainwater preventing splashes thus improving visibility and safety for vehicles. The article noted that porous asphalt costs relatively the same as conventional asphalt. However, the stone recharge bed is more costly than the traditional base. This cost difference can be offset as the amount of stormwater pipes and inlets needed are reduced. Moving from the summary, the use of porous asphalt should be increased as it has benefits to safety, pollution and sustainability when compared to the conventional road surface.

One such reason is the improvements to safety. During heavy rain a thin layer of water and sometimes puddles usually form on the road. This can cause bright lights to be reflected from the water and tyres to lose traction and skid. However, porous asphalt is able to drain and sometimes prevent this thin layer of water from forming thus reducing glare and improving traction. This helps drivers to control their vehicles better during heavy rain and reducing accidents.

Another reason is the reduction in pollution. Porous asphalt helps to mitigate sound pollution as on average when compared to conventional asphalt it reduces the noise level by three decibels. This is done as the noise generated by rolling tyres is reduced as the sound that travels into the ground is greatly absorbed by the air voids in the porous asphalt. This air voids help to reduce traffic noise and increases the comfort of people living within the vicinity of these roadways. Porous asphalt helps to reduce water pollution by allowing surface runoff to seep through the ground instead of washing into drains, porous asphalt is able to help replenish groundwater and maintain the hydrology of a site. Sometimes the water will instead runoff into the soil at the side of roads and this can cause soil erosion which will lead to an increase in sediments in waterways which could cause clogging and result in a decline in aquatic life.

The final reason is sustainability, porous asphalt can be made of recycled concrete aggregate. Using recycled concrete aggregates it will still maintain its drainage function and can be used in low-strength applications like pedestrian and cyclist pathways. When this mixtures is modified by adding enhanced asphalt binder, it can meet the requirements set by Singapore’s Land Transport Authority to be used in normal highways. By being able to use recycled concrete aggregates in it’s construction, porous asphalt becomes a lot more sustainable and reduces the amount of waste generated thus freeing up space in landfills as well.

While porous asphalt can be viewed as sustainable and green it does require more frequent maintenance when compared to conventional asphalt roads. This will lead to more trafficking limitions when maintenances are carried out which can result in traffic jams and more emissions.

In conclusion, the benefits to safety, pollution and sustainability proves that porous asphalt should be used more widely to help combat the negative impact vehicular transportation has on the environment and people.

Reference: 

(Pavegreen, n.d) Porous Asphalt is King of the Road. Pavegreen. http://www.pavegreen.org/index.php?option=com_content&view=article&id=58:king-of-the-road&catid=35:porous-asphalt&Itemid=110

(Chen, 2016) Design and performance of porous asphalt mixture for predestrian/cyclist applications in Singapore. ntu. https://dr.ntu.edu.sg/bitstream/10356/67037/1/thesis_draft6.pdf

(Paving Finder, n.d) Asphalt Environmental Impact – An Eco Friendly Paving Material. pavingfinder. https://pavingfinder.com/expert-advice/asphalt-environmental-impact/

(Chen & Wong, 2013) Porous asphalt mixture with 100% recycled concrete aggregate. tandfonline. https://www.tandfonline.com/doi/abs/10.1080/14680629.2013.837839