United States Department of Transportation
i
Mitigation of Corrosion in Continuously Reinforced Concrete Pavement
-
2013-04-01
[PDF-24.29 MB]
Details:
-
Creators:
-
Corporate Creators:
-
Corporate Contributors:
-
Subject/TRT Terms:
-
Publication/ Report Number:
-
Resource Type:
-
Geographical Coverage:
-
Edition:Executive Summary; July 2010 to April 2013
-
Corporate Publisher:
-
Abstract:Between 1995 and 2009, the South Dakota Department of Transportation (SDDOT) replaced over 250 miles of two-lane interstate with continuously reinforced concrete pavement (CRCP). After being in service for less than 15 years, several of these pavement sections showed signs of distress, including Y-cracking, network cracking, and cluster cracking. A previous SDDOT study concluded that the impact on performance of these recently constructed CRCP interstates from progressing corrosion of the reinforcing steel due to deicing chemicals is uncertain. Therefore, a separate study was necessary to assess the extent of reinforcement corrosion in South Dakota CRCP interstates, which is the topic of this research. Three main objectives were addressed: determine the character, extent, and severity of corrosion in CRCP constructed since 1995; identify factors that contribute to observed levels of corrosion; and investigate cost-effective maintenance and rehabilitation mitigation strategies so that the service life of the pavements may be achieved. Field work included general observations, crack mapping, dust sampling, core sampling, and half-cell potential measurements of existing CRC pavements. Field work also included evaluating corrosion mitigation products that were applied to pavement test sections. Laboratory work consisted of chloride ion analysis on core and dust samples, and SEM analyses on selected CRCP reinforcement. Laboratory work also consisted of casting reinforced concrete specimens that used mix designs similar to the pavements evaluated in the field. The half-cell potentials for each specimen were monitored during the duration of the research project. Four of the laboratory specimens were also tested using chloride ion analysis and SEM techniques. General observations showed that there were areas of severe spalling, but severe corrosion was not observed. The vertical and lateral chloride profiles indicated that chloride concentrations were above the chloride threshold of 1.244 lbs./yd3 in the top one inch of pavement, and were generally above the threshold within the first half inch of a crack. Testing of the laboratory specimens showed similar results. SEM analyses generally showed limited to no signs of corrosion. This research also showed a strong correlation between crack density and elevated half-cell potential measurements. The results of this study show that observed pavement distresses are likely not the effect of corroded reinforcement and that reinforcement at cracked locations is the main area that is susceptible to corrosion caused by deicing salts. The field testing of the mitigation products did not show any conclusive evidence that they reduce the corrosion of CRCP. Portions of the laboratory testing did show an increase in half-cell potential (reduction in corrosion), in comparison to the control specimens, but for other types of specimens no significant difference between the control specimens and specimens tested with sealers and MCIs were found. The SEM analyses of each of the specimens tested showed small amounts of pitting corrosion, but no difference in corrosion from specimen to specimen was observed.
-
Format:
-
Funding:
-
Collection(s):
-
Main Document Checksum:
-
Download URL:
-
File Type:
