|
|
|
Title: VISUAL EXAMINATION OF STRUCTURAL DAMAGE IN WISCONSIN & DISCUSSION
Accession Number: 00218289
Record Type: Component
Abstract: FIELD OBSERVATIONS BY MAINTENANCE PERSONNEL ARE REPORTED OF DAMAGE TO STRUCTURES CAUSED OR CONTRIBUTED TO BY THE USE OF DEICING AGENTS FOR WINTER MAINTENANCE. SURFACE DAMAGE TO BRIDGE DECKS IN WISCONSIN OVER THE PAST FIVE YEARS IS PARTICULARLY HEAVY BECAUSE A HIGH RATE OF CHEMICALS HAS BEEN APPLIED TO THE HIGHWAYS DURING THE WINTER. MOST OF THE SCALING NOTED IS CONCENTRATED IN AN AREA ABOUT 4 FT. WIDE TOWARD THE CENTER LINE FROM THE OUTER EDGE OF THE SUPERSTRUCTURES. THIS AREA SHOWS THE MOST SERIOUS DETERIORATION BECAUSE MELTED SNOW OR ICE FLOWS LATERALLY OUTWARD FROM A CROWDED ROADWAY OR IS SPLASHED OUTWARD BY PASSING VEHICLES. SAND, SNOW, AND OTHER DEBRIS TEND TO BUILD UP NEAR THE CURB AND OBSTRUCT THE FLOW TO THE FLOOR DRAINS, PARTICULARLY ON STRUCTURES BUILT ON A RELATIVELY FLAT GRADE. THE SALT BRINE THEN CONCENTRATES IN THIS AREA AND TROUBLE DEVELOPS. SINCE 1947, AIR-ENTRAINED CONCRETE HAS BEEN USED EXCLUSIVELY FOR BRIDGE DECKS. ALTHOUGH IT IS TRUE THAT SUCH AIR-ENTRAINMENT APPARENTLY INCREASES THE RESISTANCE TO FREQUENT FREEZE-THAW CYCLES AND THE RESULTANT SURFACE SCALING, AIR-ENTRAINMENT ALONE CANNOT PROVIDE THE ANSWER. THE LACK OF ACCURATE FIELD CONTROL OF AIR CONTENT HAS BEEN NOTED IN A NUMBER OF CASES WHERE SCALING HAS BEEN OBSERVED ON DECKS CONSTRUCTED WITH AIR-ENTRAINED CONCRETE. BESIDES THE LACK OF ACCURATE CONTROL OF AIR CONTENT DURING CONSTRUCTION, THERE ARE SOME OTHER PHASES OF CONSTRUCTION OPERATION THAT MAY HAVE BEEN CARELESSLY PERFORMED: (1) IMPROPER PLACEMENT OF REINFORCING STEEL, (2) POOR CONSOLIDATION OF CONCRETE AT CONSTRUCTION AND EXPANSION JOINTS, (3) CARELESS FINISHING OPERATIONS, PARTICULARLY OVERFLOATING, RESULTING IN A THIN SURFACE COAT OF MORTAR THAT EASILY POPS OFF AND EXPOSES THE COARSE AGGREGATE TO DETERIORATION, AND (4) LACK OF ACCURATE SCREEDING AND FINISHING TO GRADE, RESULTING IN SHALLOW POCKETS AT THE GUTTER LINE PERMITTING PONDING OF WATER AND SALT BRINE. SURFACE TREATMENTS ARE BEING EXAMINED TO MINIMIZE FURTHER DAMAGE.
Supplemental Notes: No 323, pp 15-18 Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
Monograph Title: Monograph Accession #: 01410704
Authors: Aten, C EDiscussers: Oleson, C C
Publication Date: 1962
Serial: Conference:
41st Annual Meeting of the Highway Research Board
Location:
Washington DC, United States Media Type: Digital/other
TRT Terms: Geographic Terms: Old TRIS Terms: Subject Areas: Administration and Management; Construction; Highways; Maintenance and Preservation; Vehicles and Equipment
Files: TRIS, TRB
Created Date: Jul 29 1994 12:00AM
More Articles from this Serial Issue:
|
