Street maintenance work includes crack sealing, pothole repair and patching, chip seals, cape seals, asphalt overlays, and complete reconstruction of roadways. Routine street maintenance activities such as crack sealing, patching, and pothole repair are performed by the streets division of the public works department.
Large street maintenance projects such as pavement overlays or street reconstruction are generally classified as capital projects and are managed by the Engineering Department.
A Community Priority
In a community survey conducted by the city in 2016, the “condition of city streets” ranked as the second-highest citizen priority among city services, a priority directly linked to the highest-ranking priority in the survey, namely, “traffic flow and congestion management.”
The city maintains an inventory of all streets and assigns each a pavement condition index based on industry-standard practices. These data are used in conjunction with community feedback to prioritize street improvements using available funding. Additional detail can be found in the city’s Street Maintenance and Capital Plan.
Montrose Moving Forward maintenance work is budgeted under the city’s General Fund. Where appropriate, resources from the city’s Water and Sewer Funds will be used to perform utility improvements within certain project areas.
The city performs different types of maintenance work, depending on the condition and specific needs of each street segment. Types of work include crack seal, asphalt patching, chip sealing, cape seal, asphalt overlay, and complete replacement.
Crack sealing is the first line of defense against water intrusion below the asphalt pavement. Preventing water from penetrating into the pavement will prevent further failures from developing such as potholes and alligator cracks. 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 seasonal temperatures.
The process requires clearing the cracks of any foreign material utilizing mechanical brushes, blowing the cracks out with compressed air, and filling the prepared cracks with flexible asphalt material. Crews progress quickly causing only temporary lane shifts and closures. After the material has cured, the roadway will be swept to remove any debris removed during the cleaning process.
Full depth asphalt patching is used to repair areas of isolated failed pavement. The city patches distressed areas such as, pot holes, severe alligator crack, and utility trenches. This process involves removing the section of failed asphalt, reconditioning or replacing the aggregate base, and replacing with new asphalt.
Projects are typically completed on same day. Depending on patch size and location, the patch may be prepared one day, and patched the following day.
Capes seals are a combination of two traditional maintenance techniques, chips seals and slurry seals. This technique is utilized when the existing pavement is beginning to show signs of distress such as cracking, minor potholes, and limited rutting. Prior to the pavement condition deteriorating further, a cape seal can be applied to existing roadways to prevent further deterioration while improving the overall pavement condition and usability of the road.
The cape seal process involves many activities. Prior to the application of the cape seal, necessary asphalt patchwork, and crack sealing will occur. Once all necessary patching has occurred, the roadway will be thoroughly cleaned. The first application will be of a traditional chip seal. This consists of a single application of liquid asphalt which is then covered by a cover aggregate. Traffic can return to the roadway after the cover aggregate has been rolled into to the liquid asphalt.
After a curing period of approximately two weeks, the final application of a slurry seal will occur. A slurry seal includes a suspension of aggregate in an oil/water emulsion. Curing takes between 2 to 6 hours, depending on weather conditions, turning into a thick tough mat. The road may be opened back up to traffic after the material has finished curing.
Cape seals are typically very well received from a variety of user groups, including motor vehicle drivers, and cyclists. Where appropriate, the city is taking advantage of the new surface as an opportunity of reconfiguring pavement markings with the installation of center turn lanes and bike lanes to improve traffic flow and improved safety for cyclists.
The asphalt overlay process provides a new pavement driving surface on existing streets. This technique is utilized when the existing pavement has deteriorated to a condition that a traditional chip seal or cape seal will not sufficiently correct the deficiencies. However, the condition of the road has not yet deteriorated beyond the point of requiring a full replacement.
The asphalt overlay process involves many activities. Prior to the actual overlay, necessary concrete repairs, asphalt patches, installation of new American Disability Act (ADA) access ramps will be completed. Many overlay projects will include some portion of milling of the existing pavement prior to the installation of new asphalt. Asphalt milling allows for the removal of minor surface deficiencies, maintaining the center crown height, while also allowing the new overlay to match adjacent gutter lines. After the necessary prep work has been completed the installation of new asphalt will begin. This typically includes placing two inches of new hot mix asphalt.
To finalize the project, pavement markings, and roadways signs, will be replaced. All attempts to minimize the duration of closures will be made. Often times maintenance may occur through lane shifts or closures. Where appropriate, the city is taking advantage of the new surface as an opportunity of reconfiguring pavement markings with the installation of center turn lanes and bike lanes to improve traffic flow and improved safety for cyclists.
Complete Asphalt Replacement
Complete asphalt replacement provides a new full depth asphalt pavement on existing streets. This technique is utilized when the existing pavement has deteriorated to a condition that an asphalt overlay will not sufficiently correct the deficiencies, and the extent of patching required to bring the pavement to a condition acceptable for an overlay is less economical than a full replacement.
The complete asphalt replacement process involves many activities. Prior to the actual asphalt replacement, necessary concrete repairs, installation of new American Disability Act (ADA) access ramps, replacement of aging sub-surface utilities such as water and sewer lines will be completed. After necessary prep work has been completed the existing asphalt will be removed. This will be completed using traditional excavation machines or with the added efficiency of a milling machine.
After the existing asphalt is removed, the remaining base, will be reconditioned, compacted and proof rolled to confirm the strength of the soil. New asphalt varying in depth ranging from three to five inches, depending on the type of roadway will be installed. To finalize the project, the installation of pavement markings, necessary roadways signs, and final site restorations will occur. Depending on the extent of concrete replacement and subsurface utility replacement, road closures may range from a few days to multiple weeks. Where appropriate, the city is taking advantage of the new surface as an opportunity of reconfiguring pavement markings with the installation of center turn lanes and bike lanes to improve traffic flow and improved safety for cyclists.
The chip seal process involves many activities. Prior to the application of the chip seal, necessary asphalt patchwork, and crack sealing will occur. Once all necessary patching has occurred, the roadway will be thoroughly cleaned. Chip Seals consist of a single application of liquid asphalt which is then covered by a cover aggregate. Traffic can return to the roadway after the cover aggregate has been rolled into the liquid asphalt.
After a curing period of approximately two weeks, the roadway will be swept of any loose aggregate and a final application of fog seal will occur. A fog seal is an emulsified asphalt which helps prevent the top aggregate from becoming dislodged under traffic. This helps to prevent chipped windshields and extend the life of the chip seal. Curing takes between 2 to 4 hours, depending on weather conditions. The road may be opened back up to traffic after the material has finished curing, ahead of final striping.