The ability of a road surface to withstand years of abuse is something that, as you might have guessed, is very important. But how do road builders test the performance of different materials?
Well, in France they use the Fatigue Carousel, which looks like a huge spinning top with four arms. Each arm contacts the road using road tires and the arms are designed to simulate the weight of a heavy vehicle.
It’s all attached to a mid-engine that produces over 1,000 bhp (746 kW/1,014 PS) and spins the wheels around a road ring made of any material under test. This particular machine, located in Nantes and filmed by YouTube’s Tom Scott, is one of the largest in the world and can run at speeds of up to 100 km/h (62 mph), although it normally runs faster nearly 70 km/h (43 mph).
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The facility has several rings, each 120 meters (394 feet) long, and the tests last no more than a few hours. In fact, to simulate 10 to 20 years of use, the machine must run non-stop for months at a time.
Each ring should have a small control piece of familiar building material for reference, but the rest can be made of any other material. This facility is testing roads made of greener materials and also roads with an inductive load built in to test their longevity.
Mass Installation is a fascinating look at the amount of work that goes into creating something that we tend to not really think about until something goes wrong. Even in a time when computers have facilitated virtual simulations, real-world facilities like this are needed to validate those simulations and keep roads safe.