Why Does Pavement Need to Be Flexible?
You'd think that pavement would need to be very strong and sturdy to withstand everything it goes through. It does have to be strong and sturdy, but it does not have to be rigid and unmoving, as "strong" and "sturdy" often imply. Pavement fares better when it's flexible, as asphalt often is. Bitumen is a component of asphalt, and a newer process known as foamed bitumen stabilisation appears to hold the answer to the question of how to make pavement very strong without compromising on its flexibility.
It Has to Bear Pressure Without Breaking
Pavement used for road surfaces and car parks has to bear a lot of weight as heavy vehicles travel over it. The weight of each of these vehicles presses down on the particular spots where the wheels connect with the pavement. Very rigid pavement could crack under this pressure. Road materials are chosen and laid down according to the estimated weight and amount of the vehicles passing over it, and rigid pavement has a greater chance of cracking when there are higher weights.
Flexible pavement, on the other hand, is better at bending a bit under the weight to allow the vehicle to pass without cracking the surface of the road. Flexible pavements have their limits, of course, but if the road paving is configured to support the estimated weight of normal traffic on that road, the flexible pavement should stay in better shape.
Foamed Bitumen Can Add Strength While Still Allowing Flexibility
Foamed bitumen is produced when water is injected into the bitumen. The two, when at different ends of the temperature scale, produce an expanding material that is then mixed with the paving material, binding to the particles of the paving material and binding them together. This process is called foam bitumen stabilisation. The result is a very strong paving material that is also very flexible. This can help the pavement stay intact when an excessively heavy truck travels over it, for example.
It Has a Track Record of Excellent Performance in Flooding
Flexible pavement made with foamed bitumen is apparently also wonderful for withstanding flooding. Floodwaters can wash away pavement as the ground underneath erodes and the constant contact with water gradually breaks up the pavement. In 2017, roads paved with foamed bitumen survived a tropical cyclone and its subsequent flooding completely intact. Rigid pavement that didn't use foamed bitumen would not have fared as well.
Strong, flexible roads have a much better chance of staying in good shape despite heavy vehicles, flooding, and other conditions. Foamed bitumen stabilisation is a cost-efficient process that makes flexible pavement even better to use.
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