BRIDGE DECK DEICING STUDY PHASE B-SUMMARY OF EXPERIMENTAL WORK AT TEST SITE ON INTERSTATE 80
THE BRIDGE SITE IS INSTRUMENTED WITH A COMPLETE WEATHER STATION AND THERMOCOUPLES TO MEASURE THE TEMPERATURE PROFILE BOTH IN THE BRIDGE DECK AND APPROACHWAY SURFACE. INSTRUMENTATION TO DETECT THE PRESENCE OF MOISTURE ON THE BRIDGE DECK IS ALSO INSTALLED. EVIDENCE BASED ON ANALYSIS OF THE TEMPERATURE PLOTS DOES NOT SUPPORT THE GENERALLY ACCEPTED THEORY THAT PERIODS OF FREEZING OCCUR BECAUSE THE BRIDGE SURFACE TEMPERATURE FALLS MORE RAPIDLY THAN THE ADJOINING ROADWAY. INSTEAD IT IS CAUSED BY THE FACT THAT OVER SEVERAL DAYS OF GRADUAL AMBIENT COOLING, A TEMPERATURE DIFFERENTIAL BETWEEN THE BRIDGE AND ROAD SURFACE DEVELOPS BECAUSE THE OVERALL AVERAGE BRIDGE TEMPERATURE DECLINES BELOW THAT OF THE APPROACHWAY. THERE ARE VERY FEW DAYS DURING THE WINTER WHEN THIS TEMPERATURE DIFFERENTIAL DOES NOT EXIST. ANYTIME THE TEMPRATURE DIFFERENTIAL EXISTS AND THE APPROACHWAY IS NEAR 32 F, PREFERENTIAL FREEZING MAY OCCUR IF THE PROPER TYPE PRECIPITATION FALLS. FOR EXAMPLE, IF FREEZING RAIN FALLS, IT WILL FREEZE ON CONTACT WITH THE BRIDGE BUT MELT ON THE APPROACHWAY. IN ANALYZING THE DATA, A "PROBABILITY OF FREEZING" WAS ASSIGNED TO EACH DAY BASED ON AN EXAMINATION OF ALL DATA COLLECTED. THIS WAS NECESSARY AS NO METHOD OF RELIABLY DETECTING THE PRESENCE OF ICE REMOTELY IS PRESENTLY KNOWN TO EXIST. /AUTHOR/
-
Corporate Authors:
Pennsylvania State University, University Park
Pennsylvania Transportation Institute, Transportation Research Building
University Park, PA United States 16802Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC United States 20590Pennsylvania Department of Transportation
1215 Transportation and Safety Building
Harrisburg, PA United States 17120 -
Authors:
- Biss, D J
- Publication Date: 0
Subject/Index Terms
- TRT Terms: Bridge decks; Deicing; Freezing; Moisture content; Temperature; Thermocouples
- Subject Areas: Highways; Maintenance and Preservation;
Filing Info
- Accession Number: 00218068
- Record Type: Publication
- Source Agency: Federal Highway Administration
- Report/Paper Numbers: Study No 68-35
- Files: TRIS, USDOT, STATEDOT
- Created Date: Feb 15 1972 12:00AM