Civil Engineering

 

Date of this Version

8-2011

Comments

A Thesis Presented to the Faculty of The Graduate College at the University of Nebraska In partial Fulfillment of Requirements For the Degree of Master of Science' Major: Civil Engineering' Under the Supervision of Professor Christopher Tuan. Lincoln Nebraska: August 2011

Copyright 2011 Barbara M. Gerbino-Bevins

Abstract

The cost of deicing chemicals is a significant part of the Nebraska Department of Road's winter maintenance budget. Many products are available for use in highway and bridge deicing and new products are introduced each year. The objectives of this research are to develop a laboratory test to evaluate the performance of chemical deicers, to investigate national, state, and local standards, and to develop best maintenance practices to optimize the use of chemical deicers.

This research project consists of two phases:

Phase 1: conduct a literature survey to find data from existing laboratory tests used to evaluate deicer performance.

Phase 2: develop a laboratory test to evaluate the performance of chemical deicers and correlate the results with field data from roadway maintenance. Use the data from the laboratory, the field, and the literature survey to develop a summary of the best use of chemical deicers.

The laboratory tests were developed by obtaining samples of sodium chloride, magnesium chloride, calcium chloride, potassium acetate, and beet juice based chemical deicers for evaluation. Two of the magnesium chloride based deicers were made from byproducts of the ethanol industry. The deicers were tested for ice melting performance, resulting pavement friction, the effect from direct sunlight, and the time to refreeze after application.

The field data was collected by the Nebraska Department of Roads using Automatic Vehicle Location (AVL) systems installed on plow trucks in concert with the Maintenance Decision Support System (MDSS). The MDSS is a computerized system that collects weather data from area weather stations and gives maintenance crews recommended application rates for different weather events.

The Shaker Test was developed to evaluate the performance of chemical deicers. The test works well for assessing the ice melting capacities of liquid and solid deicers, but more research is needed for prewet solids. The beet juice based deicers were found to perform well at temperatures as low as 14°F when exposed to direct sunlight. A summary was compiled to outline the recommended standards of practice for anti-icing and de-icing operations using the selected deicing chemicals during particular types of winter storms.