What are Porous Pavements?

What are Porous Pavements? 

Porous pavements, both asphalt, and concrete are around for years. In most areas, they haven’t really caught on. Now, with the massive specializes in environmental issues and green buildings, are they worth watching again? Pavement design Traditional pavement design Typically when pavement mixes are designed, they include different sizes of aggregate. They use a good range from fine sand to coarse stone. the most important size depends on the expected use of the fabric. Then it's all bound alongside binder or cement. With asphalt pavement that top layer will continue a waterproof layer then a base. Concrete pavement may continue a base or directly on the bottom. This leads to an impenetrable surface that blocks rainwater from stepping into spring water systems and increases runoff. Porous pavement design Porous pavement or pervious pavement is meant using medium and enormous sized aggregate with no smaller fines like sand. it's then held together using cement or binder. the shortage of fines within the mix creates relatively large pore space within the pavement. this massive pore space allows water to undergo. The top layer is placed either directly on the bottom or on other porous base layers to permit water to empty completely through the system into the bottom. Pros and Cons Here are some pros and cons also like a couple of notes on them. Pros Increased water quality – Oils, heavy metals and other contaminants on the pavements aren't carried downstream and into stormwater drainage systems. Also, water is filtered because it passes through the pavement. Lower initial construction costs – Construction costs could also be lower because porous pavements lower the number of stormwater drainage facilities that a site will need. Fewer and smaller inlets, detention ponds and storm drain pipes mean lower construction costs. Lower future costs – less maintenance needed for storm drain and filtration systems. Fewer fees – Stormwater impact fees could also be lower since porous pavements are proven to scale back runoff. Less runoff – Less runoff means less potential flooding and lower peak flows. Increased safety – Since water drains through the pavement there's a lower chance of hydroplaning and a rise in traction. LEED Points – It can indirectly help gain LEED Points. It can contribute to the areas of Stormwater Design, Heat Island Effect, Water Efficient Landscaping, Recycled Content, and Regional Materials. There could also be other ways in which using it can help LEED certification. Cons Higher initial construction cost – Yes, I do know I listed construction cost as a professional also. the value of constructing the pavement itself tends to be above the regular pavement. Soil restrictions – The soil below the pavement must drain a minimum of also because of the pavement. Clogging – The pores within the pavement may clog. Suppliers and other proponents say that regular cleaning and maintenance will nearly eliminate clogging. Pavement strength – Porous pavements are structurally weaker than standard pavements. That generally leads to them getting used just for low traffic roads and parking lots. Extra care must be taken when designing pavement for top traffic or heavy traffic. New/Untested technology – That’s not entirely accurate. The technology has been tested for a minimum of 1971. However, most contractors don’t have experience with it. Proper training, clear instructions, material testing, and site investigations should be done to make sure that the pavement meets all applicable standards during construction. Contamination – Pavement surfaces usually have tons of contaminates on them. Porous pavements can filter contaminants, but no system is 100%. Since water drains directly into ground soil it's possible that it'll take the contaminants with it. Conclusions There is tons of potential for porous pavements in future projects. Each project would need to be investigated independently to work out any cost or environmental savings that may be gained by using porous pavements. However, the potential positives do seem to outweigh the potential negatives. it might certainly be worth some time to research it and present your findings to your client. 

What are your thoughts on Porous and Pervious Pavements?

Er.SP.ASWINPALANIAPPAN., M.E.,(Strut/.,)

Structural Engineer

Madras Terrace Architectural Works

www.civilbaselife.blogspot.in