Asphalt Milling in Houston, TX
Asphalt milling is a restoration-focused process designed to remove an existing layer of asphalt down to a prespecified depth. Pavement contractors rely on planing machines (typically a cold planer) to precision grind the asphalt surface away while leaving the deeper pavement layers and underlying base intact.
The goal of asphalt milling is twofold and involves the following processes:
- Remove a worn or damaged asphalt surface to make way for a fresh surface course of asphalt.
- Texture the remaining pavement to promote better adhesion for the new surface course.
Asphalt milling requires an expert crew, the right equipment and best practices to accomplish both of these objectives, and American Paving is a trusted Houston paving contractor that is ready for the task.
What Pavement Services Require Asphalt Milling?
Asphalt milling is almost always part of a pavement restoration project, though it may also be required for some full pavement replacement jobs as well. Specifically, your property will require asphalt milling for the following paving processes:
- Asphalt overlaying or resurfacing – Asphalt overlaying and other surface treatments are necessary when the existing surface course has sustained excessive wear or damage. It is standard practice to schedule an asphalt overlay when the pavement is about halfway through its useful life, which is typically between 10-15 years. Before the new asphalt can be installed, the existing asphalt surface will be milled down first.
- Drainage installation or adjustments – Asphalt milling can be used to slope the pavement, which can promote better drainage or alter the drainage patterns on an existing piece of asphalt.
- Pavement transitions – Transitions are the spots where one piece of pavement connects to another, and if these transitions are not installed properly, there may be differences in height that need to be evened out. Asphalt milling is done to smooth out these transitions.
- Spot texturing – Spot texturing is important for certain applications, like installing road shoulders. Asphalt milling is used to produce the kind of texture that drivers will feel and hear if they veer onto the shoulder.
- Full-depth pavement replacement – Full depth pavement replacement is typically performed without asphalt milling, but planers can be used to mill asphalt down to its full depth prior to removing it from the project site.
- Asphalt overlaying or resurfacing – Asphalt overlaying and other surface treatments are necessary when the existing surface course has sustained excessive wear or damage. It is standard practice to schedule an asphalt overlay when the pavement is about halfway through its useful life, which is typically between 10-15 years. Before the new asphalt can be installed, the existing asphalt surface will be milled down first.
What Does the Asphalt Milling Process Include?
Asphalt milling is a multi-step process that involves the following:
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- Site access and traffic control – Several machines are deployed during an asphalt milling job and form a train, which means your pavement contractor will need space to operate. To establish that space, the pavement team may need to carve out additional site access and will likely need to cordon off parts of the parking lot or road to ensure motorist and pedestrian safety.
- Milling and removal – Once the project site is secured, the pavement work begins. The primary machine involved in asphalt milling is the cold planer, which steadily passes over the asphalt and uses a carbide-tipped drum to grind it down. This drum is precisely positioned to ensure cuts are made at the proper depth.
As the existing asphalt is milled down, the pulverized remains are directed into hauler trucks. From there, the haulers may either take it to a landfill for disposal it can be recycled into a new batch of asphalt to save money and time.
- Site cleanup – Following milling, the exposed pavement surface must be thoroughly cleaned to ensure the new asphalt adheres properly. This includes power sweeping and may involve vacuuming the exposed surface as well.
- Inspection and proofing – Before a new surface course of asphalt is installed, the pavement team will verify the integrity and load bearing potential of the remaining pavement layers and base. This is done through a proofing process during which a heavy piece of equipment like a loaded hauler is rolled over the pavement. If the pavement buckles under the equipment’s weight, it is removed and the underlying base is stabilized.
The next steps in the process will depend on the nature of your pavement project, but will likely include the following, as well:
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- Tack coating – Tack coating is essential for promoting adhesion between the existing pavement and the new surface course. Without tack coating, the new hot mix will wear (and fail) quickly. The tack coat is an asphalt emulsion that is spray-applied to the exposed, milled pavement. It is deposited in a precise layer, and once it cures it will act like “glue” for the new layer that will follow.
- Asphalt paving – The last step in many asphalt restoration projects is laying down and rolling out a new layer of hot mix asphalt. Once the old surface course is milled down and removed, the surface is cleaned and tack coat is applied, the pavement team will install a fresh layer of hot mix.
What Best Practices Should Asphalt Milling Teams Observe?
Asphalt milling is a process that is managed with best practices at the forefront. These best practices ensure the pavement is properly managed and prepared for any type of restoration project.
Those best practices include:
- Precise milling machine control – The most important part of the asphalt milling process is ensuring the planer is operating at the right speed and at the right depth. Both are key to producing a smooth, even cut along the pavement’s surface.
- Proper milling drum maintenance – The milling machine drum must be inspected prior to every operation to ensure the teeth are sharp enough to make precise cuts. If the drum’s teeth are too dull, they will transfer vibration into the asphalt’s deeper layers, which can damage the pavement’s base and result in long-term durability issues.
- Thorough pavement cleaning – Once the asphalt surface is milled down, the pavement team cannot cut corners during the cleaning phase. Poor cleaning will mean poor adhesion when the new asphalt is laid down.
- Detailing pavement edges – Milling machines generally aren’t designed to fit right up against curbs or other drainage elements. To resolve this, reputable pavement contractors will use a smaller planer that’s designed to mill the asphalt’s edges to the same depth.
- Asphalt recycling – Recycling milled asphalt is not just an environmental concern as it also greatly reduces disposal and material costs. As such, a reputable pavement contractor will strive to repurpose as much of the milled asphalt as possible for their clients.
Asphalt milling is a critical part of many pavement services, including restoration and replacement projects. It must be done within tight specifications and while observing best practices, as any misstep will mean your new surface course of asphalt will fail early.
To ensure your asphalt project is executed to success, partner with a pavement contractor that has invested in modern milling machines and has a history of projects similar to yours. Asphalt milling is a process that pavement teams perfect through repeated execution, so choose a contractor that can demonstrate its mastery. If you are in need of asphalt milling services, reach out to American Paving to get your project underway.