Road Preservation Projects
Road Preservation Program
The Annual Road Preservation program treats numerous surface treatments on our hard-surfaced roads. The information below outlines various road preservation treatments that are used by the Boone County Highway Department.
Hot Mix Asphalt (HMA) Overlay
A hot mix asphalt overlay, often referred to as “repaving” or “resurfacing” is a maintenance technique utilized when the condition of the roadway surface is in fair to poor condition. Typically, the Boone County Highway Department bids Hot Mix Asphalt (HMA) resurfacing projects to contractors who specialize in asphalt paving. Due to budget constraints, Boone County does not typically have enough highway funding to reconstruct the entire roadway, therefore, our resurfacing projects often include some deep patching to repair areas of pavement which have signs of deterioration in the lower levels of existing pavement. The worst areas are identified and patched prior to the final resurface coat being applied to the pavement.
Hot Mix Asphalt (HMA) Structural Overlay
A hot mix asphalt structural overlay, much like a standard Hot Mix Asphalt (HMA) overlay is often referred to as “repaving” or “resurfacing”. However, a structural overlay is utilized when the condition of the roadway shows signs of significant and wide spread deterioration and considered to be in poor condition. In addition to the placement of a new surface, a layer of stronger HMA pavement is placed before the surface to improve the overall strength and longevity of the pavement. The projects will also include deep patching to repair areas of pavement which have signs of failing subgrade. Typically, the Boone County Highway Department bids Hot Mix Asphalt (HMA) resurfacing projects to contractors who specialize in asphalt paving.
Chip & Seal
The purpose of Chip & Seal is to protect water from infiltrating into our hard surfaced roadways and provide a new skid resistant surface on the roadways. This process, which is performed by our own crews, is one of the most cost effective pavement treatments for roadways and extends the life of the County’s roadway assets. The Boone County Highway Department may place either a single layer of new chip and seal or a double layer chip and seal, depending on the current condition of the roadway.
Cold Mix Asphalt (CMA) Overlay
A cold mix asphalt overlay, often referred to as “repaving” or “resurfacing” is an alternative to a hot mix overlay on low volume roadways. This surface treatment is completed in its entirety by the Boone County Highway Department, including the mixing, trucking and placement (paving) of the material. Due to the porosity of Cold Mix Asphalt, a chip and seal is placed the year following its initial installation. Cold mix asphalt is not a lesser product than Hot Mix Asphalt. In fact, many of the County’s CMA overlays outlast Hot Mix overlays.
Water penetration through pavement surface cracks one of the most common reasons for premature pavement failures. Therefore, crack filling is the most cost-effective tool to reduce water penetration into pavements and extend the life of our paved roadways. This treatment is typically used on our roadways that are in good condition and is applied during the winter months. The roadways to be crack filled are selected annually based on the condition rating inspections and assessments. Some years, the Highway Department may implement multiple crack fill projects, some will be completed in the Spring months and others in the Fall/Winter months
Microsurfacing is a preventative maintenance technique used to help preserve and protect the underlying pavement structure and provide a new driving surface. Roads chosen for microsurfacing are often streets with low to moderate distress and narrow crack widths. It consists of the application of a mixture of water, asphalt emulsion, aggregate (very small crushed rock), and chemical additives to an existing asphalt concrete pavement surface and extends the pavement surface before a hot mix asphalt overlay must be performed. The Boone County Highway Department selects the roadways to be microsurfaced annually after the pavement condition ratings are completed.