All 30 sample replicates for Sealants A and C were characterized with a tensile stress-relaxation experiment (strain of 15 % ± 0.2 %) prior to exposure. Following the characterization, four samples of Sealants A and C were placed in the outdoor custom dynamic strain devices in the early spring of 2007. Additional sample sets of three replicates of Sealants A and H were placed in the same exposure environment with gage blocks to impart static 0, 5, 10, 20, and 25 % tensile strains and clips to impart 5, 10, 20, 25, and 30 % compressive strains; these replicates were placed in the same outdoor environment as the dynamically strained samples. All specimens were monitored over the summer (May 10-September 1). In the fall (September 1), the samples were removed from the
FIG. 2—Plot of the strain versus date for the summer exposure (May 10-September 1) of the dynamically strained samples.
testing fixtures, forced into their original configurations, and characterized again by stress-relaxation experiments.