News — DOT

Road Salt Brine Concentration: A Field Guide to Measuring Salt Brine for DOT Road Deicing

When winter weather arrives, transportation departments and road maintenance crews have a simple objective: keep roads safe while using the minimum amount of deicing material necessary to do the job.

That sounds straightforward. In practice, effective winter road maintenance depends on getting several variables right at the same time: pavement temperature, precipitation, traffic, timing, application rate, chemical selection and, when liquid deicing brine is used, the concentration of the solution being applied.

For sodium chloride road salt brine, concentration is especially important.

A solution that is too weak may not provide the expected freezing-point depression or melting performance. A solution that is too concentrated is not necessarily better. In fact, sodium chloride brine has a well-defined optimum concentration, and exceeding that concentration can actually raise its freezing point and create operational problems.

For road departments, municipal public works crews, airports, private snow-removal contractors and other winter maintenance operations, a portable refractometer provides a fast way to verify that salt brine is being produced and applied at the intended concentration.