If you ever questioned the value of salt for deicing, take a moment to check out the video, Bumper cars on ice in Portland, OR .
Any driver who ever experienced the total lack of control on ice, as the poor folks in this video did, will never have to be convinced of the value of deicing!
Road salt is a life saver!!
Winter finally arrives -- big time! Though storms have crippled transportation in the Plains and Rockies, the first significant storm struck a broad swath from Texas through New England over the past few days. Texas Gov. Rick Perry's inaugural was postponed due to icy road and the Associated Press reports 41 storm-related deaths . We've had our wake-up call.(photo: Kelly Kerr/Tulsa World, via The Associated Press)
The Transportation Research Board's Performance Measurement Committee's newest newsletter was published today, containing an article by Salt Institute president Dick Hanneman on the role of roadway friction measures to rate the effectiveness of winter maintenance efforts . "Friction measuring devices create accountability for outcomes for the first time," explained Hanneman. Hanneman serves as liaison between the TRB Performance Measurement Committee and TRB's Winter Maintenance Commitee.
Highway maintenance operators are continually barraged with advertising claims on the benefits of various deicing compounds. The number of conflicting claims out in the marketplace make it difficult to arrive at a decision one can comfortably live with. One of the areas of greatest contention is the effect of various deicing chemicals on pavement concrete.
I recently took part in an excellent Snow and Ice Meeting at Villanova University organized by Greg Nichols of Bryn Mawr College. During the course of that meeting, one of the speakers, who represented a deicing technology company in Iowa, told the participants of the highly deleterious effects of sodium chloride on concrete. Of course, it was the job of this individual to sell his particular brand of product. But was what he said about the deleterious effects of sodium chloride on concrete correct?
Among its various roles, the Salt Institute carries a strong educational component. In serving that role, we have to make use of the most reliable, objective sources of information available. With reference to the latest research on the impact of various deicing chemicals on pavement concrete we turned to Iowa State University's Department of Geological and Atmospheric Sciences.
In a comprehensive paper authored by H. Lee, R. D. Cody, A. M. Cody, and P. G. Spry, entitled,
Effects of Various Deicing Chemicals on Pavement Concrete Deterioration
these researchers described their comprehensive investigations into the effects of different deicers on concrete deterioration. The materials they used were sodium chloride, calcium chloride, magnesium chloride, calcium magnesium acetate (CMA) with 5 different Ca/Mg ratios, Ca-acetate, and Mg-acetate. Each deicer produced characteristic effects on the concrete samples by physically and chemically altering the dolomite coarse aggregate, the dolomite coarse aggregate-paste interface, and the cement paste.
Their study conclusions revealed that magnesium in any form was the most damaging to the concrete. Magnesium chloride produced significant concrete crumbling and that calcium magnesium acetate (CMA) solutions were the most damaging of all solutions tested. Wet/dry and freeze/thaw cycling in CMA produced widespread and severe damage. Magnesium acetate produced similar damage.
Most significant of all, under the experimental conditions they employed, sodium chloride was the least deleterious material to concrete.
