Performance Rating of De-Icing Chemicals for Winter Operations

Chris Tuan, Ph.D., P.E. Barbara Gerbino-Bevins, Civil Engineer

Mike Mattison, P.E.

Objectives

• Research and develop standardized tests to analyze the performance of chemical deicers

• Correlate laboratory data with field data• Research and develop best practices regarding the

use of chemical deicers

Overview

• Literature Survey• Shaker Test

– Procedure – Results

• Field Data Collection– Road Condition Rating System– MDSS and AVL Data

• Best Practices

Literature Survey

• Chemical Deicers– NaCl, MgCl2, CaCl2 , Potassium Acetate, “Beet

Juice”– Liquids and Solids

• Practices– De-icing: Reactive– Anti-icing: Proactive– Prewet Solids

Literature Survey

• SHRP Handbook of Test Methods for Evaluating Chemical Deicers– SHRP Ice Melting Capacity Test: Does not

correlate well with field data– Resulting roadway friction after treatment – Ice penetration and Ice debonding– Thermal Properties

• Research Sponsored by Clear Roads and Northwest Pacific Snowfighters

Shaker Test

Martini ShakerThermocouple

1-mL Ice Cube TrayFreezer

Shaker Test Results

Shaker Test: Liquid Results

Shaker Test: Liquid Results

Shaker Test: Liquid Results

Shaker Test: Beet Juice Results

Shaker Test: Solid Results

K Ace Reaction

Shaker Test: Conclusions

• Test Results– Low Variance for Each Temperature Group– K Ace Reacts with Road Salt– How Beet Juice Works

• The Shaker Test– Quick, Simple, Inexpensive– Repeatable– Produces Consistent Results for Liquids and

Solids at 20°F, 10°F, and 0°F

Field Data Collection

• Maintenance Decision Support System (MDSS) – Web-based software– Records Vehicle Location– Weather Data

• Automatic Vehicle Location (AVL)– Time Stamps of Plow Truck Locations– Records Data about Chemical Application– Takes Pictures from the Cab

Field Data Collection

• Maintenance Decision Support System (MDSS)– Weather Data

Field Data Collection

• Maintenance Decision Support System (MDSS)– Records and time stamps vehicle location

Road Condition Rating System • Based on what can be seen from the truck

– Lines and wheel tracks• 100% Covered

– Cannot see roadway

• 75% Covered– Can see some roadway– Cannot see two defined, continuous wheel tracks or any

lines.

Road Condition Rating System• 50% Covered

– Can see two defined, continuous wheel tracks– Cannot see lines

• 25% Covered– Can see two or more wheel tracks– Can see one or more lines

• 0% Covered– Can see inner and outer lines– Little or no snow is on roadway

Beet Juice Treatment with and without Sunlight

Road Salt Treatment under High Winds

Best PracticesLiquids

• Best used at temperatures greater than 20°F• Pencil nozzles work well for post-treatment of ice or

compacted snow layers greater than ¼ inch. • Best choice for anti-icing• Can be used during events with precipitation rates less than

0.5 in/hr• Retreat every 1½ to 2 hours to prevent refreeze

Solids• Can use at temperatures as low as 12°F• Works well for post-treatment of ice and compacted snow• Smaller gradations tend to work faster, but also refreeze

quicker • Coarse grained deicers can be used during events with

precipitation rates greater than 0.5 in/hr

Best Practices

• Not recommended to use deicers or abrasives if wind speed is greater than 15 mph

• Abrasives with a pre-wet are much more effective than dry abrasives

• MgCl2 and CaCl2 work better than NaCl at temperatures lower than 20°F, but can cause slippery roads if humidity is higher than 40%.

• Beet juice works well in direct sunlight

Conclusions

• Shaker Test can be used to screen new deicers or compare the performance of different deicers

• Field Data Collection– Processing MDSS and AVL Data is Time

Consuming– Provides Useful Snow Events Information for

Correlation Study– More Data Required for Statistical Significance

Acknowledgments • NDOR Technical Advisory Committee:

– Jasmine Dondlinger, Jodi Gibson, Lieska Halsey, Wally Heyen, Dalyce Ronnau, Amy Starr, and Gary Story.

• District Maintenance Managers:– Ray Branstiter, Dale Butler, Kelly Doyle, Chris

Ford, Allen Horak, Roger Klasna, and Roger Kalkwarf.

• City of Omaha Public Works:– Scott McIntyre.

Slide design © 2009, Mid-America Transportation Center. All rights reserved.

Barb Gerbino-Bevins, NDORMike Mattison, NDOR

Chris Tuan, Ph.D., UNL

CREDITS