Advanced Materials

Ordinary concrete on longer required as part of this sustainable neighborhood

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I attended a trade show a few months ago after which I realized the sustainable materials of our future were closer to being a reality than I thought.

Pervious – not just any cement

Pervious concrete is a durable concrete pavement with a larger amount of voids in its structure than found in conventional concrete. Like conventional concrete, pervious concrete consists of a mixture of cement, coarse aggregates, and water. Pervious concrete differs from traditional concrete since little or no sand is utilized which results in a porous open-cell structure which allows water to pass through readily.

The problem with typical concrete and the result of the ensuing impermeability

The concrete which is we are accustomed are solid surfaces which prevent water from penetrating into the ground. When storm water encounters impermeable surfaces, pollutants are picked up as the runoff flows into storm drains. The contaminated water flows directly into rivers, lakes, wetlands and oceans, which generates problems for biodiversity as well as public health.

Another consequence of typical concrete is surface water flooding and erosion of stream banks. During periods of heavy rainfall, large amounts of impermeable surfaces generate large amounts of runoff which can cause flash floods.

Finally, once the impermeable surfaces send rainwater into storm drains instead of allowing the flow to percolate down to the aquifers the groundwater may be depleted faster than its recharge rate. This depletion results in the water table not being adequately recharged.

What can this pervious concrete achieve?

The primary benefit of using pervious concrete is when the rain which falls soaks into the ground instead of flowing across a hardscape, picking up contaminants, and getting sent through pipes to the nearest body of water. The end result is the land gets returned to its pre developed hydrology, while maintaining the useful hard surface we prefer to live, work, play and drive on.

Solutions under foot

Sustainability materials are closer than you think – in fact, pervious concrete might be supporting your feet at this moment. Something for the sustainable individual to keep in mind when considering installing new concrete where ever you live.

 

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