We park on asphalt parking lots and drive on asphalt highways and roads every day, but how often do we think about the equipment required to build them?
Let’s take a look at the equipment needed to construct these asphalt surfaces and how it’s used.
Milling machines are used to remove the top layer of an existing pavement before a new asphalt layer is laid. Milling can remove only the surface or the entire depth of the pavement, known as full-depth removal. Paved areas may need to be milled to level the surface or repair the damaged layer.
A milling machine, also called a cold planer, is a heavy-duty piece of equipment with a large rotating drum. Cutters inside the drum rotate and cut up the existing asphalt surface to the required depth. A vacuum sucks up the milled material where it’s loaded onto a conveyer belt attached to the milling machine. Water is typically applied to the drum during the milling process to reduce the machine’s extreme heat and minimize the dust milling causes. A dump truck moves alongside the milling machine to collect the material as it’s removed. This method saves both time and effort. The milled asphalt is recycled and used in other projects.
After the asphalt pavement has been milled, a sweeper is used to clean the surface. Large particles of debris can cause uneven compaction of the asphalt. Even small amounts of dust and debris left on the ground can prevent the new asphalt from bonding properly with the surface below. It’s also necessary to sweep after milling to prevent small rocks from hitting the oncoming traffic and damaging vehicles’ windshields.
Most asphalt paving job sites use several types of dump trucks to haul asphalt from the plant to the job site. Here are some of the most common ones:
Bottom Dump – Bottom dump trucks are also known as belly dump trucks because they release their load from underneath instead of spilling it out like standard dump trucks. Sloped internal walls guide the asphalt out through opened gates.
End Dump – These trucks raise the front end and let the asphalt slide down the bottom of the bed and out the back through a tailgate. End dump trucks are popular because they are versatile and easy to maneuver.
Live Bottom – Live bottom, or flo-boy, dump trucks have a conveyor system at the bottom of their bed to unload their payload. Hot Mix Asphalt (HMA) is discharged out of the trucks’ bed without raising the bed. These trucks are more expensive to operate and maintain because of the conveyor system, but they can decrease segregation problems because the HMA is moved out in large piles. They can also eliminate some potential types of truck bed paver contact because the bed isn’t raised during the unloading process.
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