Summary/Reader Response Draft #1: Porous Asphalt Pavement
The article “Porous Asphalt Is Kind Of The Road” (PaveGreen n.d.)
introduces the features and application of porous asphalt, a type of road surface
used to improve safety, diminish water pollution and decrease erosion. The
article state that porous asphalt is made up of rocks glued together with
asphalt cements while lowering the amount of fine aggregate. This allow rainwater
to seep through the space between the rocks and limiting the flow rate of water
therefore reducing surface runoff, there are multiple way to combine porous
asphalt to achieve different objective. It was further stated in the article
that during winter climate porous asphalt require less anti icing agent which
reduce the amount of chloride from being released into the environment which is
toxic to aquatic life. On highways, spaces in between the rocks allow rainwater
to seep in between and reduce the splashes thus improving visibility and safety
for vehicles.
The article mentioned that the porous asphalt roads cost
relatively the same as conventional asphalt, typically porous asphalt have to
be used together with a base layer such as stone recharge bed to achieve
optimal result this results in a higher cost for installing porous asphalt. However the cost different can be offset from
the reduced amount of stormwater pipe and inlet to be built.
The article explained the benefits and multi-purpose application
of the porous asphalt, however the routine assessment and maintenance required
for porous asphalt for it to perform optimally and when compared the durability
of porous asphalt against the traditional dense asphalt pavement, the porous
asphalt are deem have a lifespan as compared to the latter. These disadvantages
of will significantly affect the applicability of and cost of maintaining
porous asphalt when compared with traditional roads. However, if provided a
suitable condition and specialist personnel, porous asphalt can be a more ecological
and greener alternative to traditional roads.
Firstly, while porous roads asphalt act as a
filtration for containment such as oil and minerals, without routine assessment
and maintenance and over a period of time as containments and sediment are
constantly being filtered out, the pores of porous asphalt will be blocked. The
article “Effect of Clogging on the Permeability of Porous Asphalt Pavement” (Yaolu
Ma, Xianhua Chen, Yanfen Geng, and Xinlan Zhang) it is stated that clogging characteristic of the porous
asphalt pavement is a common problem owing to deposition of sediments on the
pavement surface, the storm water, and vehicles. The clogging causes 59%
- 75% reduction in permeability, which causes the ideal characteristic of porous
asphalt to be obsolete. Therefore routine assessment of porous asphalt is required
to determine the number of when are maintenance required to ensure that the condition
of porous asphalt is optimal. The article “A Review of Permeable Pavement
Clogging Investigations and Recommended Maintenance Regimes” mentioned that there is no universal superior maintenance
method, assessment and monitoring of porous asphalt should be conducted early
after installation even if there are no sign of blockage. Continuous monitoring
of permeable pavement surfaces is necessary to better understand the in situ
clogging mechanisms for a particular region.
Secondly, the existence of high void content in between porous
asphalt which provide its permeability causes the structure of porous asphalt
to be weaker than traditional dense asphalt when place under consistent strain
where multiple vehicle run over. The article “Investigation of microstructure
characteristics of porous asphalt with relevance to acoustic pavement performance”
states that the problem with high void content of porous asphalt is intentionally
designed for its functional properties and the drawback of such design consist
of material deterioration, such as ravelling effect and increased physical
aging effect. This affect the applicability of porous asphalt in expressway and
roads that experience high amount of traffic. The lifespan of porous asphalt
roads in such area will be greatly reduced.
Lastly, one of the key characteristic of porous asphalt that are
not mentioned in the article is that it is able to reduce noise created. This
characteristic is especially useful in countries and area where the land is a
limited resource such as Singapore. In Singapore, due to the constraint of
limited land, roads and express are built in the vicinity of our HDB Flat. As vehicle
went past the roads and express way in large quantity, large amount of noise are
created. The article “Noise reduction effect of double-layered porous pavement[AT1] ” (KONDO, N OHNISHI, H Hattori, T ISHIKAWA, KNAKANO,
T, 2000) state that
porous pavement are considered to be one of the most effective countermeasures
for countering traffic noise, result shown that noise reduction on porous
pavement is about 3-4dB compare with the traditional roads.
In conclusion, even with benefits and advantages of porous asphalt,
when deciding to replace traditional roads it is important to take into
consideration of the climate and location of implementation as building it in
location that are unfavourable might cause more cost and effort into maintaining
its functionality.
Effect of Clogging on the Permeability of Porous Asphalt
Pavement
https://www.hindawi.com/journals/amse/2020/4851291/
Noise reduction effect on double-layer porous pavement
Effects of double layer porous asphalt pavement of urban
street on noise reduction
https://www.sciencedirect.com/science/article/pii/S2212609016000029
Porous Asphalt is king of the road
Investigation of microstructure characteristic of porous
asphalt with relevance to acoustic pavement
performance.
https://www.sciencedirect.com/science/article/pii/S2046043017300722
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