County Road Maintenance Program

Once a road has deteriorated to a point where preventative maintenance is no longer a viable option, then other corrective actions become necessary. Each road is different. Roads have different traffic loadings, different soil conditions, different existing materials in the pavement structure, and different drainage characteristics. By analyzing the existing road conditions, we determine whether to improve, replace or construct pavement structures underneath the roadway surface on a case-by-case basis. The worst-case scenario for corrective actions involves total reconstruction. The time, equipment and material costs associated with total reconstruction are many times greater than preventive maintenance. That is why preventive maintenance is so important. To view a list of County Roads to receive major maintenance this year, visit the Roads page.

Road and Bridge is dedicated to maintaining the County's roadway infrastructure using the most appropriate engineering solution in a cost-effective manner. In keeping with that duty, we also aim to provide major maintenance to as many roadways as resources will allow. Road and Bridge is continually searching for construction and material opportunities that will increase production while still providing the most appropriate solution and a high-quality product.

One road that was recently rehabilitated utilizing innovative construction means and methods was CR 424, from CR 414 to CR 425. Two different methods were used to stabilize and strengthen the existing material. Section 1) CR 424, from CR 414 to approximately 1 mile South of CR 425, was rehabilitated utilizing a process that injected hot asphalt cement that was turned into a foam and injected into the existing material to stabilize and strengthen the base material (foundation), and section 2) used a specialty emulsified asphalt to blend in the existing material to also stabilize and strengthen the base.

The rehabilitation of Section 1 (pictures below) was a joint collaboration that included Williamson County Road and Bridge and two equipment providers, Cooper Equipment and the Wirtgen Group. These companies supplied technical expertise, equipment, and operators at no expense to Williamson County. If you would like to learn more about this project, please view the Initial Pavement Design Report (PDF) for the pavement design proposal (of the designs that were proposed, Option 1 was selected).

The rehabilitation of section 2 on CR 424, included the use of a specialty emulsion that was blended into the existing material. This procedure was also utilized on CR 426 (pictures below). The specialty emulsion is applied to the surface of the existing roadway and a roadway reclaimer follows behind to obliterate the existing material and mix the asphalt into it. The material is then graded and compacted. Once the roadway material has had time to cure, the surface is then treated with a seal coat.

An asphalt emulsion consists of asphalt particles suspended in water. Under normal circumstances, oil (asphalt is a petroleum product) and water will separate and not mix. However, when an emulsifying agent is also included in combination with the asphalt and water, the asphalt will stay dispersed in water. When the water evaporates, the asphalt particles remain and help bind the material. In the case of the specialty emulsion that was used on CR 426, the asphalt is the product of sweet crude oil and has been chemically altered to strengthen the material and decrease its permeability.