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.
Pavement Design and Testing
ParklandGEO can provide pavement related from preliminary and detailed design through to post-construction pavement management, maintenance and rehabilitation. We offer pavement related design recommendations as part of many of our geotechnical engineering projects as well as the following specialized pavement services:
CCIL Certified aggregate lab (Type D Advanced)
CCIL Certified technicians for testing
Superpave mix designs and aggregate testing
Construction testing for pavement materials and roads
ParklandGEO usually undertakes pavement design as part of municipal infrastructure or industrial/ residential land development projects; and provides designs based on pavement assessments for reconstruction/ upgrade projects on existing roadways. We have provided designs for flexible asphalt concrete pavements (ACP), rigid Portland cement concrete (PCC) pavements, roller compacted concrete (RCC) pavements, interlocking paver block/ slab pavements and granular pavements including pads and resource roads on muskeg.
ParklandGEO has considerable experience undertaking pavement assessment and failure investigations on industrial, urban road and highway project sites. In Western Canada most hard surface roads are constructed with ACP. We are very familiar with Pavement Management System evaluations for ACP, including structural assessments based on deflection testing, visual condition assessments, ride comfort indexes, etc. While we subcontract major deflection testing projects (i.e. FWD or Dynaflect), we have the ability to undertake localized pavement deflection testing for smaller projects using Benkelman Beam equipment. We have experience using a number of subgrade, base and pavement reinforcement options including: geotextiles, geo-grids, geo-cells, cement stabilized subgrade, cement stabilized base (soil cement), Full Depth Reclamation (foamed asphalt base), Deep Asphalt Base Replacement, ACP layers with Polymer Modified Performance Grade Asphalt Cement and composite pavements including PCC pavement layers. Our innovative knowledge in pavement technology helps us to provide our rehabilitation project clients with optimized pavement designs and reduced life cycle costs.