Treatments

“Don’t judge a road by its surface”

A road is composed of multiple layers of material, each performing separate functions, from providing stability and strength to allowing for proper drainage. The surface of the road – the part we see – is merely one of those layers.

Just as our own skin protects our bodies from harsh elements that can compromise our health,  the surface layer of a road protects the integrity of the layers beneath, which in turn, extends the road’s overall service life.  

When we speak about preserving a road, we’re not only talking about the surface people drive on but, more importantly, the integrity of what lies beneath the surface.

That is why roads are designed to receive periodic treatments to protect the integrity of its multiple layers of material. To do this, KCRC has a “toolbox” of surface treatments from which to choose. Treatment selection is based on a variety of factors, including the current pavement condition, the ride quality, and the volume of traffic a road carries.

Ultra Thin Overlay

An Ultra Thin Overlay is a preventative surface treatment used on roads in good and fair condition to extend pavement life. The process places approximately ¾” of hot asphalt over the existing surface.

Benefits: Ultra Thin Overlay helps to extend pavement life by providing a top “seal” that reduces water infiltration and oxidation. It improves the ride quality of the road and provides a smoother, uniform black appearance to the surface that improves aesthetics and visibility of pavement markings.

Challenges: To be effective, warm conditions (60 or higher) with little to no chance of rain are necessary for application.

What to Expect: The curing time for ultra thin overlay material varies on the pavement surface conditions and the weather at the time of application. Under ideal conditions, it is suggested that traffic be kept off the treated surface for at least two hours. Road closures or lane closures are used depending on traffic volumes and work zone safety considerations. Typically, while one lane is being treated, local traffic will be allowed on the opposite lane.

Mill & Fill

Mill & Fill is a structural pavement treatment that involves the removal of the existing surface layer - and in some cases the entire asphalt pavement thickness - with a milling machine and the replacement of the milled location with new asphalt. This process is used when a surface has deteriorated to poor condition and surrounding grades (i.e. curbs, driveways) must be met.

Benefits: Mill & Fill restores and strengthens a road’s surface layer by restoring the pavement to a “like new” condition.

Challenges: The Mill and Fill process costs considerably more than preservation treatments like chip seal or micro surface. When a road has deteriorated to poor condition, pavement preservation treatments no longer provide long-term improvements and structural reconstruction is required.

What to Expect: The Mill & Fill process can take a few days to several weeks to complete depending on the length and width of the project. It is weather dependent, and multi-day lane closures, road closures and detours may be instituted.

Micro-Surface

A Micro-Surface is a preventative maintenance treatment that provides a durable, polymer-modified asphalt emulsion to roads that are just beginning to show signs of aging and minor distress. The existing pavement is covered with a thin application that restores a uniform black color, provides a new surface and extends the surface’s service life. Micro-Surface can be used as a stand-alone process or combined with other preventive maintenance methods. For instance, a cape seal is a treatment that combines a chip seal with a Micro-Surface.

Benefits: Micro-Surfacing preserves pavement by protecting the surface from the effects of natural aging and the environment. It can extend the life of pavement by as much as 7-10 years by restoring the wearing surface of a roadway and sealing out moisture. Micro-Surface prevents oxidation that can cause deterioration and more costly repairs down the road. The pavement’s darker color also increases the road’s temperature which benefits winter maintenance.

Challenges: The application of a micro-surface is weather-dependent, requiring dry, moderate-to-warm weather conditions.

What to Expect: The application generally takes one day and road closures will be enacted. A treated surface can be driven on within a few hours of the application.

Fog Seal

Fog Seal is a light application of asphalt emulsion sprayed onto a pavement’s surface. Fog Seals are effective complements to new and aged chip seal surfaces because the asphalt emulsion secures the aggregate from the chip seal process and locks it into place.

Benefits: Fog Seal helps to extend pavement life by providing a top “seal” that reduces water infiltration and oxidation. It provides a smoother, uniform black appearance to the surface of the road that improves aesthetics and visibility of pavement markings. The pavement’s dark color also increases the road’s temperature which benefits winter maintenance.

Challenges: To be effective, warm conditions with no chance of rain are necessary to ensure successful fog seal application.

What to Expect: The curing time for the fog seal material will vary depending on the pavement surface conditions and the weather at the time of application. Under ideal conditions, it is suggested that traffic be kept off the fog seal material for at least two hours. Typically, while one lane is being treated, traffic will be allowed on the opposite lane.

Crush & Shape

Crush & Shape is a structural pavement treatment that grinds, or crushes, the existing asphalt and 1-2” of underlying gravel. The material is then regraded, compacted and covered with multiple layers of paver-placed hot asphalt.

Benefits: Crush & Shape restores and strengthens a road by reconstructing the pavement to a “new” condition.

Challenges: The Crush & Shape process costs considerably more than preservation treatments like chip seal or micro surface. When a road has deteriorated to poor condition, pavement preservation treatments no longer provide long-term improvements and structural reconstruction is required.

What to Expect: A mile of crushing & shaping generally takes a week to complete, and another week is needed for the asphalt paving. Local traffic is maintained during the process and a detour is provided for through traffic.

Crack Seal

Crack Seal is the process of filling cracks and joints with asphalt materials, which keep water out of the pavement. When water is kept out, pavement deterioration is slowed. Crack Seal can be used on its own or in preparation for an additional preservation treatment, such as Chip Seal.

Benefits: Filling or sealing pavement cracks to prevent water from entering the base and sub-base can extend the pavement life by 3-5 years.

Challenges: Crack Seal application requires dry conditions and is restricted by precipitation. Therefore, inclement weather will delay application.

Because cracks do not typically form in straight lines, a Crack Sealed road may appear to have dark squiggly or “spider-like” lines running along it. Because of this, Crack Seal is typically not as aesthetically pleasing as other pavement preservation options.

What to Expect: Typically, Crack Sealing requires intermittent lane closures for the selected road, and work is completed same day.

Chip Seal

Chip Seal is a pavement surface treatment that combines a layer of asphalt with a layer of fine aggregate to provide a high friction-wearing surface over old pavement. An application of asphalt emulsion is sprayed onto the road surface, which is then covered with pea-sized stone aggregate. Rollers follow to embed the crushed aggregate into the emulsion.

After the Chip Seal cures (approximately 1-2 months), a Fog Seal will be applied. This application helps to significantly reduce tire noise, eliminate dust, and bind the remaining aggregate into a smooth, black, hard-wearing surface.

Benefits: Chip Seal can extend pavement life by 5-7 years. It also increases the “friction factor” of the roadway surface, helping to reduce the number of wet and snow-related vehicle accidents. It is cost-effective, allowing KCRC to treat twice as many roads when compared to the next lowest-cost surface treatment.

Challenges: Chip seal application is typically applied from June to August because it requires warm, dry conditions. It is restricted by precipitation; inclement weather will delay application.

After chip seal is successfully applied, a certain amount of aggregate will work loose during the curing process (approximately 1-2 months), and there can be dust post-application.

The high friction (rough) surface enhances traction but can be challenging for non-motorized transportation.

Preparation: Road damage, such as potholes and cracks, are repaired by KCRC crews prior to the Chip Seal process. In addition, low hanging branches and overgrowth may be trimmed.

What to Expect: The Chip Seal process is generally accomplished in one day, and intermittent lane closures are often used to allow drivers access. Post application, the new surface can be driven on almost immediately, but because of the emulsion and loose aggregate slow speeds are required.

After the Chip Seal process, excess loose aggregate is swept off the roadway by mechanical sweepers. The roadway surface will continue to improve as the surface stabilizes, resulting in a stronger more durable surface. After the Chip Seal cures (approximately 1-2 months), a Fog Seal will be applied.

Cape Seal

Cape Seal combines two preservation treatments, Chip Seal and Micro-Surface, to extend the life of a road. During the Chip Seal process, an application of asphalt emulsion is sprayed onto the road surface, which is then covered with pea-sized stone aggregate. Rollers follow to embed the crushed aggregate into the emulsion. The “Chip Sealed” road is then covered with a thin application of a polymer-modified asphalt seal, or Micro-Surface.

Benefits: Cape Seal combines the strength of a Chip Seal with the smoothness of a Micro-Surface. The combination restricts water penetration, which reduces the formation of cracks and other subsequent damage to the road bed. The combination also provides a smoother surface than would a Chip Seal alone, which is friendlier to non-motorized vehicles, and creates a uniform black appearance that improves aesthetics and visibility of pavement markings.

Challenges: Both applications require dry conditions and are restricted by precipitation. Therefore, inclement weather will delay application.

A certain amount of aggregate applied will work loose as the chip seal cures (approximately 1-2 months), and there can be dust present for a few days after the application. However, the micro surface application will significantly reduce tire noise, eliminate dust, and bind the remaining aggregate into a smooth and hard-wearing surface.

Preparation: Road damage, such as potholes and cracks, are repaired by KCRC crews prior to the Chip Seal process. In addition, low hanging branches and overgrowth may be trimmed.

What to Expect: The Chip Seal process is generally accomplished in one day, and intermittent lane closures are often used to allow drivers access. Post application, the new surface can be driven on almost immediately but, because of the emulsion and loose aggregate, slow speeds are required.

After the Chip Seal process, excess loose aggregate is swept off the roadway by mechanical sweepers. The roadway surface will improve as the surface stabilizes, resulting in a stronger more durable surface.

After the Chip Seal cures (approximately 1-2 months), the Micro-Surface is applied. This application is generally completed in one day and road closures will be enacted for the application. The new surface can be driven on 1-2 hours after the application.