Typically, Muench says, the solution isn’t too complicated: just build higher infrastructure. But engineers can’t build roads and bridges to withstand every disaster, which would lead to high-priced, overbuilt projects that “would take generations to complete,” Muench says.
Dear Rice Krispie.
As engineers rebuild roads from scratch, they also began using different materials to account for the possibility of huge volumes of water flowing in very quickly. Over the past decade, road builders have increasingly installed more permeable, “spongy” roads.
Permeable concrete, unlike regular concrete, usually excludes sand from the typical “gravel, sand, cement, water” recipe. It also has a lower water-to-cement ratio, which causes it to form a bulky paste before drying. “It’s like caramel popcorn or a Rice Krispie bar,” says Nara Almeida, who studies the material as an assistant professor in the civil engineering program at the University of Washington Tacoma.
On ordinary concrete roads, water accumulates and accumulates, and the standing water eventually destroys the various layers, especially the critical layers underneath that bear the hefty loads of vehicles. However, the increased porosity of permeable concrete allows water to flow more easily through the material so it can reach the ground and be absorbed – a beneficial feature for roads exposed to high humidity.
Permeable concrete has its disadvantages. It is weaker than regular concrete, which means it is better suited for sidewalks, parking lots, and low-traffic streets than interstate highways where there are many hefty trucks. (Tests Reinforcement of the material with steel, natural, glass and synthetic fibers is in progress.) Its porosity means it is not best suited to frigid climates, where water can seep into the material, freeze and break it down. Concrete also requires regular pressure washing or vacuuming to “unblock” it of materials often found on the road – dust, leaves. Because states sometimes have to change suppliers and processes to operate newer materials, projects can cost them more. But in some places, the problem lies with interstate highways, Almeida says, where the risk of regular tire strikes is much lower.
Ultimately, however, there is little that can be done when a huge amount of water quickly flows over the road or the base of a bridge, which engineers call “overwash.” “We’ve all been playing in the yard with water and hoses – it’s very harmful,” says Muench, an engineering professor. Part of climate resilience is planning ahead and placing quick fix materials nearby so that communities can rebuild quickly.