Ramsey Resident - 2018 - January/February

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Salt and Ice Control This article will help answer some questions that citizens may have about ice control and what methods the City uses to provide traction on streets in the community. To start out, we first must provide some basic knowledge of the materials used in the process. Sand on its own does not have ice -melting capability. Sand is primarily used as an abrasive to provide temporary traction. Sand works best on hard packed snow where it can embed itself into the snow and remain there. When used on ice, sand has a tendency to "bounce' when it comes out of the plow truck and end up at the side of the road. The City uses a salt/sand mixture of approximately 15% salt and 85% sand. The salt prevents the sand from freezing in the pile and provides some ice -melting capability to the mixture. This sand/salt mixture is only used in extreme cold weather or freezing rain. Many larger cities and highway departments are reassessing their use of sand in their snow and ice control pro- grams. Several reasons include the cost of clean-up, the clogging of storm sewer inlets, and the rising concern over air pollution. When the sand is driven on by traffic, it is crushed into smaller particles and distributed into the air where it has a negative effect on air quality. Pure salt is used on all of Ramsey's primary roads and intersections to help control ice. Salt has a practical working temperature of 15 to 20 degrees F. This means that water normally freezes at 32 de- grees but, with the introduction of salt, the freezing temperature is lowered to the 15 to 20 degree range. The surface temperature of the road determines the amount of de-icing chemical needed and how effec- tively the chemical will work. As temperatures go down, the amount of de-icer needed to melt a given quantity of ice increases significantly. Salt is five times more effective at 30 degrees than at 20 degrees. Before a dry de-icing chemical can act, it must dissolve into a brine solution. Brine is the term used to describe the salt and water mixture. The necessary moisture needed to accomplish this can come from snow on the road surface, or from water vapor in the air (humidity) ... heat is required. Sources for this heat include the air, the sun, the pavement, or traffic friction. At extremely low temperatures many of these sources are not available. Many communities, including Ramsey, are now "pre -wetting" their salt. This is accomplished by placing a brine tank on the rear of the sanding truck to wet the salt when it comes off the spinner. Wet- ting provides moisture to make brine and speeds up the melting process. In addition, the wet salt has less of a tendency to bounce or be blown off the road by traffic. An overall savings in lost or wasted salt can be as high as 20% to 30% with the use of pre -wetting. Another chemical used to fight ice on roadways is magnesium chloride. Magnesium chloride has a practical working temperature of-15 to -25 degrees and is capable of attracting moisture directly from the air. It is very affective at temperatures below 0 degrees F and is fast acting. The City of Ramsey currently uses a liquid form of magnesium chloride to pre -treat salt in colder temperatures. With over 183 miles of roadway and some 860 intersections, the City relies on the Police Department and phone calls from citizens to alert the Public Works Department to problem areas that may occur because of extremely cold temperatures. Traffic can also cause slippery areas by tracking the salt out of an intersection, or by packing down the snow before the salt has a chance to work. Maintenance crews do initial salting as they are plowing the City streets after a storm and sometimes problem ar- eas occur before they can get back to complete the salting operation. If you have any questions or concerns, please call Grant Riemer, Public Works Superintendent at 763-433- 9863. • • O4lClned � umpaIles We Deliver Quality... Soil, sand, rock, mulch, pavers, and much more plaistedcompan ies.com .h. Ill so *10 THE SOIL EXPERTS. Elk River 1/_. prood Sponsor ofE, Plaisted Companies I N C O R P O R A T E D • 763.441.1100 Ramsey Resident • January/February 2018 11