$10 million per mile. That’s how much it now costs to build a two-lane road in the U.S. When you factor the effects of extreme heat into the equation, the budget may be higher.
When you’re constructing a road, bridge, or railway, the ideas of risk mitigation and management usually come in the form of reducing accidents, clashes, and reworks during your build. However, the infrastructure construction industry increasingly looks at risk in terms of “resilience.” i.e., how the structures they build will stand up to changing climate conditions while providing safe passage for the millions of cars, trucks, and trains that utilize them daily.
Buckling & Melting Roads
“Climate change is impacting roads in surprising ways, and contractors and engineers need to be prepared for extreme weather, sea level rise and hotter temperatures, said a panelist at the National Building Institute of Building Sciences’ Building Innovation Conference in Washington, D.C., on May 23,” according to Construction Dive.
There were 28 individual climate & weather-related events with a price tag in excess of $1 billion each in 2023 alone. 2023 set a new record for such events, continuing an upward trend, cautions the National Oceanic and Atmospheric Administration (NOAA).
As a result, the Federal Highway Administration’s Amir Golalipour, a highway research engineer in the Office of Infrastructure Research and Development, cautions that general contractors and infrastructure planners need to scuttle any climate models that rely on stationary weather patterns and plan roads, bridges, and rails that can better withstand fire, floods, and flash-freezing events. Recently, Golalipour shared the following information with Construction Dive regarding the fact that flood immersion can weaken a roadway by as much as 50%.
“Just to put that in perspective, in the city of Paradise, [California], that was part of the Camp Fire, when they removed debris, the load that they put on the pavement in two weeks was equal to 20 years of traffic.” The Camp Fire (2018) is still considered the most destructive in California history.
10 years ago, the FHWA issued Order 5520, which provides guidance to the agency, departments of transportation, state and municipal planners, and contractors on climate risk mitigation. It also requires states to consider the potential risk of future climate conditions when creating asset management plans.
To help with climate risk mitigation planning, the FHWA has created a suite of tools and resources, which you can find here.
Rails & Bridges Feel the Heat, Too
In July of 2024, Kristina Dahl, the Principal Climate Scientist at the Union of Concerned Scientists told NPR that “Heat affects all of these different types of infrastructure in different ways. For our cars and trucks that are running on asphalt roads, asphalt can deform or buckle when it’s extremely hot, so that can make road transportation difficult.”
“In terms of railroads, we know that rails can actually deform and buckle as well when it’s hot. Or if there are electric lines that the trains are connecting to overhead, those lines can sag. And that can cause problems for the trains and operators who have to sloe the trains down. When it comes to airplanes, there are a few different effects that can happen. The tarmac at our airports can deform when it’s hot, which causes problems as planes are trying to take off and land. But hot air also expands and becomes less dense. And, that makes it harder for airplanes to get to the level of thrust they need to be able to take off. So, when it’s really hot, all of these forms of transportation can be affected.”
Dahl went on to discuss how Amtrak has to slow its Northeast Corridor line to deal with the heat. Another infrastructure climate scientist, Dr. Suyun Paul Ham at The University of Texas at Arlington, recently wrote in a comprehensive piece on the subject of infrastructure and climate for The Conversation that Amtrak routinely slows its cars in the Northeast from its usual speeds to just 35 miles per hour once track temps reach or exceed 135 degrees Fahrenheit. At those temperatures, even the sturdiest steel can buckle, causing what are called “sun kinks,” which can quickly derail a train.
Just like steel rail lines can warp and kink, so too, can steel bridges. On July 8, 2024, the Third Avenue Bridge, a through-truss steel swing bridge, and the oldest in the region in its original form, became stuck in open position due to heat damage that kept the bridge from securely locking into place at the roadway. Firefighters brought tugboats into the river to spray the bridge down in an attempt to cool the expanded metal so it could close. While one could argue that the problem was due to the bridge’s age, the Third Street Bridge was partially rebuilt with new materials in 2004.
What Are Infrastructure Professionals Doing to Combat Extreme Heat Damage?
When it comes to concrete, it has long been a practice to cut the pavement slabs into sections to allow space for the slab to expand and contract with temperatures in an attempt to avoid buckling. However, with heat in excess of 100 degrees Fahrenheit for days or weeks at a time, states from Texas to Minnesota have issued additional guidance for travelers and maintenance crews. Adding extra sealant-filled, single-cut joints may provide flexibility while remaining water resistant. And, taking care not to pour concrete during low temperature periods, with more resilient and durable concrete, may also help.
The problem is that water and steel reinforced concrete simply do not mix. The structure meant to strengthen the concrete roads and bridges can cause extensive interior damage to the slab before it is evident in a visual inspection, rendering any aging concrete structure at risk to concrete cancer.
In the railway space, replacing traditionally smelted steel with martensite or hypereuctectoid rail steel, and adjusting the design of tracks could help avoid buckling.
Meanwhile, several universities, like The Smart Infrastructure and Testing Laboratory at UTA, and governmental agencies like the Federal Department of Transportation and the FHWA are all sinking significant funds into finding new ways to combat extreme heat and create climate-durable infrastructure.
Whether you’re building roads, bridges, high-rises, or any concrete structure, GPRS can provide the concrete imaging services you need to help keep your project on time, on budget and safe. We Intelligently Visualize The Built World® for customers across the nation.
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Frequently Asked Questions
How does GPRS provide accurate concrete imaging?
Ground Penetrating Radar Systems (GPRS) provides accurate concrete imaging by using ground penetrating radar waves to detect embedded objects, voids, and changes in material properties within concrete structures. The radar emits high-frequency radio waves into the concrete, and these waves bounce back upon hitting different materials such as rebar, conduits, or voids. By analyzing the time it takes for the signals to return and their strength, GPRS can create detailed images of the subsurface. This non-destructive method allows for precise identification of structural elements and potential hazards without damaging the concrete.
What is "concrete cancer," and how can it be repaired or stopped?
"Concrete cancer" refers to the deterioration of concrete due to the corrosion of the steel reinforcement within it. This occurs when water and oxygen penetrate the concrete, causing the steel to rust, expand, and crack the surrounding concrete. To repair or stop concrete cancer, the damaged concrete must be removed, and the corroded steel should be treated or replaced. Afterward, the area is patched with new concrete, and protective coatings can be applied to prevent further water ingress. Regular maintenance and inspections are crucial to mitigating the risk of concrete cancer.
