Rejuvenating Seal Coat
Rejuvenating seal coat is very cost effective in providing protection for our good pavements. This treatment is typically applied when an asphalt pavement is two to five years old. The benefit is similar to providing a protective wax coating to an enamel car paint job. These newer pavements receive a spray seal coat on the pavement surface to protect them from natural elements such as, sunlight, rain, snow, and ice. We have had success over the last 20 years by slowing down the surface deterioration (loss of fines and intermediate aggregate) of the pavement surface with this type of seal coat.
Chip seals are applied to our older pavements. These streets have lost the surface fines, but have not cracked or rutted to the extent of requiring overlay or reconstruction. This process involves cleaning the surface, providing necessary crack filling, and applying emulsified asphalt followed by rock chips. Chip seals provide additional protection from the elements, seal minor cracks, and increase skid resistance. Pavements need to be in good structural condition to be candidates for chip seal application.
Crack sealing is the first line of defense against water intrusion into the sub-surfaces (base and sub-grade) that lie below the asphalt pavement. Cracks typically appear within five years of new pavement construction. Our Colorado climate creates more cracks in asphalt pavements than many other areas of the country, based on our extreme pavement temperature fluctuations. The process requires routing cracks to an appropriate size, blowing the cracks out with heated compressed air, and filling the prepared cracks with flexible asphalt material
Major asphalt patches are required to repair failed areas in the pavement surface. We patch distressed areas such as, pot holes, alligator areas, settlements, utility trenches, and repair areas due to construction work. This process requires traffic control, removal, and replacement of the pavement. Our patching program is contracted out to a private contractor with locations city-wide.
The pavement overlay program provides a new pavement surface on existing streets that have deteriorated to a condition that chip sealing is not an acceptable treatment. The overlay process involves many activities. Prior to the actual overlay taking place, patching, utility adjustment, traffic signal actuators, and mandated American Disability Act (ADA) access ramp improvements need to be completed.
Most overlay projects include milling off a portion of the existing pavement surface, placement of a geo-textile paving fabric, and the application of a new asphalt pavement surface. This new asphalt surface is normally two to four inches thick. Collector and arterial streets require new striping with this kind of maintenance treatment. During the process, utility adjustments for manholes and water valve boxes are also required. Each street in the overlay process is evaluated for the type of overlay it will receive. These factors include traffic types and amounts, existing surface condition, and structural strength.
In some cases, a total or partial reconstruction needs to take place when a street has completely failed and even an overlay is not applicable. Pavement reconstruction involves all the aspects of a mill and overlay, except the pavement and base are totally removed, the underlying sub-grade soils are repaired and re-compacted, new base coarse material is constructed, and a total new pavement structure is constructed.