Resilient Infrastructure

Summer 2016

Pavers not only manage water better, they don't 'crack' under pressure

by David R. Smith


Resilient Infrastructure

Procrastination seems endemic to human nature. However, there may be some evidence to the contrary. Most of us might recall Superstorm Sandy in October 2012. Millions in New Jersey and New York sure do. Local governments, insurance companies, businesses and homeowners also remember some $80 billion in destruction. And this event wasn’t a hurricane.

The evidence against procrastination appears to be emerging from within the highest levels of government and among business leaders. Katrina and Sandy were catalysts. Leaders are asking how to build better to reduce damage from storms and earthquakes and accelerate recovery. Most of the discussion is on making buildings stronger, i.e., more wind-, flood- and earthquake-resistant. The conversation must soon turn to how to better build things outside buildings such as parking lots, roads, utilities and communication infrastructure.

Even flooding from smaller storms, the ones with no names, are costing millions. While investments in resilient infrastructure solutions are long-term, we are seeing an emerging trend of using permeable interlocking concrete pavement (PICP) as a means to reduce flooding. Such is the case with the Southeast Atlanta Green Infrastructure Initiative that aims to capture seven million gallons under miles of PICP streets. The first six miles are already built. This exemplifies resilient infrastructure where roads also do flood control: They mitigate it rather than contribute to it.

Another little known aspect is resilience from interlocking concrete pavement. That type of segmental pavement isn’t designed to permeate due to sand joints, bedding, and a dense-graded aggregate or stabilized base. There are reports in Canada and Italy on the ability of this system to not crack when inundated, unlike monolithic asphalt or concrete. ICP doesn’t crack when flooded because it has “cracks” in it; joints between the paving units relieve the water pressure as it builds under the pavers. And the surface can be reinstated without requiring deliveries from a ready-mix concrete or asphalt plant. (They might be flooded, too.) Rapid recovery of roads from floods or earthquakes is a prerequisite to building repair.

While lots of beautiful patios are being built, the segmental concrete pavement industry is at the threshold of entirely different conversation and market opportunity. It is poised to more readily establish and institutionalize segmental pavements as part of resilient infrastructure that yields economic, environmental and social benefits to property owners, municipalities and wider society.