Determination of Creep Compliance and Tensile Strength of Hot-Mix ...

Figure 2: Instrumented IDT SpecimenProcedurePrior to performing the creep testing, gauge points were attached to the IDTspecimens using a gluing template and a cyanoacrylate adhesive (see Figures 3(a)through 3(g)). Just before testing a particular IDT specimen, specially modified MTSadapters were mounted onto the gauge points, aligned and secured in preparationfor suspending the extensometers between each set of opposing adapters (black forvertical, gray for horizontal). Figures 3(h) and 3(i) show the mounting of theadapters.Three replicate test specimens were inserted into the temperature chamber: one thatwas instrumented with the extensometers and placed on the lower loading strip (asshown in Figure 2), and two that were not. The chamber was turned on and thetemperature control set to -21°C. Per recommendations in NCHRP Report 530,specimen temperature was monitored by using a dummy IDT specimen within thechamber that had a type K thermocouple embedded at its 3-dimensional center.Thus, the chamber temperature was necessarily set at the target test temperature±1.0°C in order to obtain an internal specimen temperature that was within ±0.5°C ofthe target temperature (as indicated by the type K thermocouple) before any testingwas performed. The basic procedure for creep testing was as follows:1. Perform a 100 second IDT creep test at -20°C on specimen #1 of the set ofthree replicates that represent a particular treatment combination of mix type7