a. Miter gate with yellow, ice-covered rub rails, similar to gate where test piles were fielded.
b. (Left) Two sample racks, each with 20 piles randomly ordered for field testing. (Right) Sample rack in place behind gate
rub rails.
Figure 4. Exposure test configuration.
Field testing
After laboratory testing at CRREL, the sample piles were mounted in random order in six test racks of 20 samples each
and installed below the full-pool elevation at Mississippi River Lock and Dam 25 (near St. Louis) in mid-January 2002. Here,
the samples were subject to periodic draining and flooding associated with normal locking operations. (Figure 4 shows the
exposure test configuration.) After six and a half months (mid-January to August 2002) of exposure to cyclical drying and
wetting, and abrasion from ice, suspended sediment, and debris, the samples were returned to CRREL. After washing with a
mild detergent, they were retested for ice adhesion. The samples were then re-racked, returned to Lock and Dam 25, and
reinstalled below waterline in November 2002. Plans call for them to be retested at CRREL after another year of field
exposure.
4
ERDC/CRREL TN-03-4
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