Pavement Management

Street maintenance progress

Pavement management plans

Asphalt overlay

One form of street maintenance is sometimes referred to as “asphalt overlay”.  Once asphalt has been laid, it can be driven on almost immediately. However, drivers are asked to watch for and respect the detour requests of flaggers as street workers put the final touches on the road, such as smoothing it out with heavy road rollers.

“The benefits of asphalt are durability, cost effectiveness, smoothness and the ability to install it relatively quickly,” said Richard Stone, public works director for the City of Columbia. “It is also a recyclable asset.”

Mill and overlay

One form of street maintenance is sometimes referred to as “mill and overlay”. This process consists of two major steps:

  1. milling the street and
  2. laying the new asphalt (overlay).

To mill the street, workers use heavy equipment to remove the surface of the street and place it into dump trucks. Workers then use a machine to spray “tack,” a liquid asphalt coating that will assistant is adhering the new asphalt to the road. The final process is overlay, which is shorthand for laying asphalt on the street.

Once asphalt has been laid, it can be driven on almost immediately. However, drivers are asked to watch for and respect the detour requests of flaggers as street workers put the final touches on the road, such as smoothing it out with heavy road rollers.

“The benefits of asphalt are durability, cost effectiveness, smoothness and the ability to install it relatively quickly,” said Richard Stone, public works director for the City of Columbia. “It is also a recyclable asset.”

Milling and overlaying a street is about five times more expensive than other options such as chip sealing, but about five to 10 times less costly than reconstruction.

“The purpose of the program is to focus on a workable and affordable plan for improving the integrity and service life of City streets over the long term, while reducing the costs associated with deferred maintenance,” said Stone.

The Columbia Public Works Department is accredited by the American Public Works Association.

Chip seal

How cost-effective is it?

The chip seal process typically costs $1-$2 per square yard. By comparison, milling off the road surface and putting down a new overlay of asphalt costs between $10 and $12 per square yard. This means that a typical 1,000-foot residential street would cost $5,000 to chip seal but more than $25,000 to mill and overlay. (Total reconstruction, on the other hand, could range between $200,000 to $350,000 for that same street.)

What is chip seal?

Chip sealing uses the same ingredients as asphalt concrete paving, but rather than milling the road and laying down new pavement, a thin film of heated asphalt liquid is sprayed on the road surface, followed by the placement of small “chips” or stones. Rollers then go over the chips to compact and adhere them to the existing asphalt. The excess stone is swept from the surface after a period of time to allow the chips to dry and settle.

What does it do?

The chip seal process is a crucial element of the City’s pavement preservation process. It prevents deterioration by sealing up cracks and providing a pliable long-term wearing surface that can typically last 5-7 years (longer if followed up by a fog seal or other treatment).

With the passage of time and vehicles over the roadway, chip seal tends to self heal the cracks in the street and protect the pavement from water intrusion (which is the enemy). Excess chips are swept up by Street Sweepers as soon as the chip seal dries but may need to be addressed several more times after that.

“We have recently been using more fog seal treatments to help better lock those chips in place,” Stone said. “People have been responding positively to that approach.”

Safety tips

During chip seal operations, and several days afterwards, drivers are advised to drive more cautiously. Please avoid speeding, turning too sharply and spinning tires.

Reclamite

Reclamite is product which can rejuvenate the oily, resinous component of asphalt which has been lost from the asphalt cement binder due to the natural process of oxidation.

We have tested Reclamite on some City streets for a few years with good results.

Reclamite is applied using a tanker truck that sprays the product on the asphalt like the chip seal binder. Once the product has cured, 15-45 minutes depending on weather conditions, the lane will be reopened to traffic.

Reclamite plays a similar role as a chip seal in that it prevents water from penetrating into the asphalt by sealing the surface. It also helps rejuvenate the asphalt by restoring maltenes that have been lost from the oxidation process. Oxidation and UV damage are reason why an asphalt street turns from black to brown to an almost gray color as it ages 

“We plan to use this product as a supplement to a chip seal’, said Seth Nelson, Pavement Management Specialist for the City of Columbia.  “Using this product with a chip seal will help us extend the life of our asphalt streets. Reclamite allows us to spray an asphalt street, that usually is less than 2-3 years old, to extend the life of that asphalt to provide an extra 5-7 years before a chip seal is needed.”

There is a cost savings with using this product over the traditional mill and overlay. The Reclamite product normally costs between $0.90-$1.05 per square yard to apply ($1.02 in 2023) while the cost to mill and overlay is $10 – $12 per square yard. 

Chip seal cost is in the range of $1.25 – $1.75 per square yard. Using Reclamite with our chip seals we can help extend the useful life of our streets which is a much cheaper alternative to a mill and overlay.

Crack sealing

Crack sealing involves using a liquid asphalt substance to seal cracks between the concrete panels of the roadway. The sealing material is covered with sand or saw-dust to reduce the amount of product from sticking to vehicle wheels. Sealing the cracks reduces the infiltration of water and subsequent roadway damage from freezing and thawing.

Pothole repair

The City has 1,450 lane miles of streets to maintain, so calls from our community members in pinpointing new potholes are always welcome and appreciated.

Potholes can occur any time during the year but tend to occur most often during and after the winter season, especially when there is a lot of precipitation and changing temperatures. Pavement expands and contracts during extreme hot and cold spells. This allows water to get under the pavement and leads to potholes. Snow plows and heavy traffic can also increase the occurence of potholes.  Street Division crews work year round to patch potholes, including during the winter when they aren’t driving snowplows, but especially when pavement temperatures are above freezing and not wet.

To report a pothole, please call the City of Columbia Contact Center with a specific location. Your report will be logged and sent to Public Works Street Division for a response.

Report a pothole

City Streets: 573.874.2489opens phone dialer

If the report is for a street maintained by the State, we will forward your message to MoDOT but MoDOT also invites you to report potholes on state roads:

State/MoDOT-Maintained Streets: 888.275.6636opens phone dialer