Figure 4 – Standard creep test frames. (Courtesy of CTLGroup)
The standard creep test consists of a frame and hydraulic loading system to apply constant stress to 150X300 mm (6x12 in.) cylindrical specimens (Figure 4).
Deformation is monitored periodically over time and compard to compansion unloaded specimens to obtain the creep strain of the concrete, which can then be used to calculate the creep compliance, or “specific creep” of the material. Tests are typically started at 7 or 28 days of age, but this test can be modified for early age by starting the test as early as 24 hours.
Sealed tests are used to evaluate “basic” creep and unsealed tests incorporate the Pickett Effect, or “drying” creep