The tool box for winter road maintenance has gotten bigger in the past few years. In the past we had plowing with the addition of salt and sand used to manage roadways. These still are part of the tool box of tools for winter road maintenance but variations have occurred with all road maintenance activities.
Perhaps the biggest variation in use is that of “Brine”. Brine is a simple chemical application of a mixture of salt and water, mixed to 23.3%. Brine is now used for all aspects of road hazard removal. Perhaps you have seen prior to a storm what looks like wet stripping along the traveled roadways. This is a pretreatment effort. Brine is applied to the roadway to accomplish a number of goals. The pretreatment allows for the brine to permeate the pavement surface helping to prevent the bond between the snow/ice and the pavement itself. This helps with the removal of snow/ice from the pavement while limiting ice spots.
Brine is also used, much like an application of granular salt, after roadways have been plowed. Using brine, the mixture is wet and allows for better adhesion than granular salt. It also jumpstarts the chemical process in allowing the salt to work faster. Salt can be disturbed and thrown off roadways with traffic movements. This makes the use of brine far more economical as less salt is used and the effect is superior to that of granular salt. A limitation with brine is its use is effective only to about zero degrees.
Another newer tool being used for winter road maintenance is treated salt. Treated salt contains magnesium chloride and a binder of either corn syrup or sugar beet solids. This material is used down to about 10 degrees below zero. It is used in areas with curb and gutters and also areas of more density in residents or traffic. In addition to the lower temperature benefit the use of these materials avoids the use of sand which can fill up storm sewers and get into peoples yards. This assists in the spring by minimizing street sweeping and the expense and dust that goes along with these operations.
The more traditional salt/sand mixture is used when temperatures require its use. They are used in hills and curves providing for extra safety. To enhance the use of this application treated brine using treated salt is used. This helps with keeping the materials where they need to be to be effective. It also then becomes more effective when temperatures increase.
As much of this is new territory for our public works crew as well as others the applications and use are somewhat a work in progress. Different roads based on sunlight, road composition, pavement and temperatures all play into the decisions about what will work best. Fine tuning with applications will continue as we seek the best answer. We have come along way from just salt and sand.
