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19 Table 10. Summary of state DOT MSE wall corrosion assessment programs. State Description References California Have been installing inspection elements with new construction Jackura et al. since 1987, and have been performing tensile strength tests on (1987), Elias extracted elements. Some electrochemical testing of in-service (1990), Coats et al. reinforcements and coupons has also been performed. LPR and EIS (1990), Coats et al. tests were performed on inspection elements at selected sites as part (2003- Draft of NCHRP Project 24-28 and results compared with direct physical Report) observations on extracted elements. Florida Program focused on evaluating the impact of saltwater intrusion, Sagues et al. (1998, including laboratory testing and field studies. Coupons were and 2000), Berke installed and reinforcements were wired for electrochemical testing and Saques (2009) and corrosion monitoring at 10 MSE walls. Monitoring has continued since 1996. Georgia Began evaluating MSE walls in 1979 in response to observations of McGee (1985), poor performance at one site located in a very aggressive marine Deaver (1992) environment incorporating an early application of MSE technology. Exhumed reinforcement samples for visual examination and laboratory testing. Some in situ corrosion monitoring of in-service reinforcements and coupons at 12 selected sites using electrochemical test techniques was also performed. Kentucky Developed an inventory and performance database for MSE walls. Beckham et al. Performed corrosion monitoring including electrochemical testing of (2005) in-service reinforcements and coupons at five selected sites. Nevada Condition assessments and corrosion monitoring of three walls at a Fishman et al. site with aggressive reinforced fill and site conditions. Exhumed (2006) reinforcements for visual examination and laboratory testing; performed electrochemical testing on in-service reinforcements and coupons. A total of 12 monitoring stations were dispersed throughout the site providing a very good sample distribution. New York Screened inventory and established priorities for condition Wheeler (1999, assessment and corrosion monitoring based on suspect reinforced 2000, 2001, 2002a fills. Two walls with reinforced fill known to meet department and 2002b) specifications for MSE construction are also included in program as a basis for comparison. Corrosion monitoring uses electrochemical tests on coupons and in-service reinforcements. North Initiated a corrosion evaluation program for MSE structures in 1992. Medford (1999) Carolina Screened inventory and six walls were selected for electrochemical testing including measurement of half-cell potential and LPR. This initial study included in-service reinforcements, but coupons were not installed. Subsequent to the initial study, NCDOT has installed coupons and wired in-service reinforcements for measurement of half-cell potential on MSE walls and embankments constructed since 1992. LPR testing was also performed at approximately 30 sites in cooperation with NCHRP Project 24-28. Ohio Concerned about the impact of their highway and bridge deicing Timmerman (1990) programs on the service life of metal reinforcements. Performed laboratory testing on samples of reinforced fill but did not sample reinforcements or make in situ corrosion rate m easurements. Oregon Preliminary study including 1) a review of methods for estimating Raeburn et al. and measuring deterioration of structural reinforcing elements, 2) a (2008) selected history of design specifications and utilization of metallic reinforcements, and 3) listing of MSE walls that can be identified in the ODOT system. Note: EIS = electrochemical impedance spectroscopy. data with geographic location and view all of the perfor- 1. Collection of data on comparison of LPR and weight loss mance data and pertinent information associated with that measurements using data available from the existing liter- location. ature augmented with additional data collected from this project. These data are useful to discern any bias with respect to LPR measurements that should be considered Type I--Measured Corrosion Rates in the reliability analysis. Consistent with the data needs for reliability analysis and 2. Study of the relationship between corrosion rate and resis- calibration of strength reduction factors for LRFD, the fol- tivity of reinforced fill materials. Resistivity is known to lowing studies were performed: have a significant impact on corrosivity, however, data