Figure B5. Complete test apparatus placed into envi-
ronmental chamber.
After the instrumentation was completed, a Plexiglass cylinder with the multi-
VIT micrometer heads through the wall was placed over the sample. The microme-
ter was used to set the range between the aluminum foil target and the transducer
prior to testing. Threaded rods were then placed between the top and bottom cap
and tightened to complete the assembly. The whole assembly was then moved into
the environmental chamber, which is part of Figure B5.
Once in the MTS, a confining pressure is applied. The confining pressure ap-
plied was conditioning pressure suggested by AASHTO TP 46-94 and CRREL test
protocol. For the cohesive soil, the specimen was cured for a minimum of three
days before testing so as to reduce the effect of thixotropy. For the cohesionless soil,
since thixotropy was not an issue, there was no curing time.
TEST METHOD
Testing was performed on a closed loop electrohydraulic testing machine. The
resilient modulus tests were run under load control using the AASHTO TP46 test
protocol. Load pulses of 0.1-second and 0.9-second rests as suggested by the test
protocol were used. Depending on the soil type, AASHTO standard TP46, Tables 1
and 2, were followed closely for the nonfrozen and thawed loading sequence. At
times, the complete sequence could not be attained because of large deformations
in the soil samples. During the tests, the rate of deformation was continuously
checked and the sequence stopped if the predicted rate at the end of the load cycle
was ≥ 2%. For the frozen resilient modulus tests, the suggested AASHTO loading
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