Public Works – Salt Brine
The City of Beavercreek Street Department this winter continues to use a new tactic to treat streets for snow and ice. Before a snow or ice event begins, City crews will line the streets with salt brine, a clear water and sodium chloride solution. It is composed of tap water and road salt, and is mixed in concentrations of 23% to 26% salt and has a freezing point of -6 degrees F.
The strategy is to pre-treat streets by applying salt brine directly to the road whenever the road temperatures are predicted to drop below freezing even when there is no snow or ice in the immediate weather forecast. The brine liquid is placed on the roadway in small streams usually across only one driving lane at a time. In clear weather, the brine will dry up leaving a bonded strip of fine salt on the pavement. During dry weather, these strips will remain on the pavement for several days, even under heavy traffic conditions. When snow or ice does contact the treated pavement, the moisture will activate the strips into brine and help prevent a snow/ice bond from forming.
The total application is usually at a rate of 30 to 50 gallons per lane mile. This equates to a cost of .0516 cents per gallon, or approximately $2.58 per lane mile for the pre-treatment. As a comparison, when salt pellets are used for its snow and ice pavement-bond-breaking capability, the amount of salt required to convert ¼ inch of ice on one lane mile of road to a liquid with a freezing point of 20 degrees F would be 8,234 lbs of salt (4.117 tons) at today’s cost of $225.
Applying brine to the pavement before snow or ice has bonded can be 10 times more effective than placing salt crystals on top of snow and ice after the precipitation has bonded to the pavement. Additionally, pre-treating is labor efficient, since the process can be performed during normal shifts. Pre-treating reduces overtime and greatly reduces the total cost of treatment, as once the snow/ice has bonded to the pavement, it is more expensive and time consuming to remove.
Beyond the material and labor savings, the ability to provide a treatment at the earliest stages of a winter event, when drivers are most likely to overestimate the driving conditions, provides an additional savings by reducing the frequency of traffic crashes.
Placing dry granular salt on the roadway as a pre-treatment for deicing is less efficient than salt brine for several reasons.
- It must be dissolved into brine before deicing can begin
- Granular salt will not bond to the dry pavement. Traffic will crush it and cause the powder to blow away
- Ohio Department of Transportation tests have proven that efficient placement of dry salt can only occur at very low truck speeds. Excessive scattering of material begins at speeds as low as 15 mph
The addition of the new salt brine process for winter weather events is a cost-saving measure that will enhance the City’s ability to help keep streets clear in the winter, while conserving the salt stockpile for more major storm events.