What More Resilient Pavement Than a Flexible Pavement?

“What More Resilient Pavement Than a Flexible Pavement?”

By Clifford Ursich, P.E., President & Executive Director of Flexible Pavements of Ohio

Last July, the National Asphalt Pavement Association reported the United States Senate Committee on Environment & Public Works unanimously approved America’s Transportation Infrastructure Act (ATIA) surface transportation reauthorization. At $287 billion in highway spending, the ATIA would be the largest transportation reauthorization in history.

The legislation includes provisions to improve road safety, speed-up project delivery, reduce highway emissions, grow the economy and improve” resiliency” to disasters and extreme weather events like wildfires, hurricanes, flooding and mudslides.

One has to wonder how a transportation bill has much to do with wildfires, hurricanes, flooding and mudslides except for the fact that when such disasters happen a strategy is needed to ensure quick recovery that removes the impediment making possible the safe and free movement of people and goods. To that end it seems to be money well invested.

Defining Resilience

Not only has the concept of “resilience” shown up in Congress, it’s being routinely discussed among engineers of various disciplines. As a civil engineer, I see it somewhat frequently in trade magazines that engineers are rethinking infrastructure designs and systems. The motivation is, first, to use materials and systems less susceptible to damage from natural disasters. Second, when damage does occur, having the capability to quickly get infrastructure “up and running” – particularly transportation infrastructure needed for emergency purposes, sustenance and commerce. The societal cost associated with failed infrastructure runs high, hence, the desire for resilience.

I’m unaware of a working definition or metric for judging infrastructure resilience – let alone our subset pavement resilience. Like the word “sustainability,” “resilience” can mean different things depending on context. However, Webster’s Dictionary helps some.I submit that the best means of judging infrastructure resilience – and pavement resilience more specifically – is by how well it achieves the desired outcome, which inferred in the ATIA highway reauthorization bill is: quick recovery.

re•sil•ience \ ri-‘zil-y n(t)s\ – 1: 2: an ability to recover from or adjust easily to misfortune or change.

When we think of quickness (in construction), asphalt typically rises to our consciousness. After all, how often have we woken from a night’s slumber only to discover asphalt crews had worked through the night and renewed the paving surface for our morning commute? The media, years ago, coined this “stealth paving.” Ease of maintenance and speed at which asphalt pavements can be repaired are unquestionably the top reasons why road agencies choose asphalt. Certainly, that has some value when we consider resilience in a transportation network.

Resilience Economics

“Resilience” has economic implications. What’s resilience worth?

How do we quantify value of a strategy? In keeping with the goal of quick recovery as inferred in the ATIA reauthorization act, speed of construction will be a large determiner of a strategy’s value. The greatest value will be from strategies that minimize user costs and inconvenience (system downtime). Speed of construction is paramount. Fortunately for asphalt, speed of construction is where we excel.

Resilience – It’s Already in the Name

The asphalt industry has a leg up when it comes to resilience – it’s already in the name! The term “flexible pavement” comes right from the engineers’ textbook and describes a pavement system that by its nature adjusts and conforms to the foundation it rests upon – unlike “rigid pavement.” That’s not a triviality; it’s the core reason engineered deep-strength asphalt pavements in Ohio have been carrying interstate loads in excess of 40 years without need for reconstruction. Being flexible makes asphalt versatile, long lasting – even perpetual. What more resilient pavement than a flexible pavement?

You may learn more about the asphalt industry in Ohio by visiting www.FlexiblePavements.org.