SHRP-A-379 traducir

NOTEA1.2.--This stress-controlled test will usually be performed at a maximum pavement design
temperature calculated at depth d in the pavement from weather data for the site of the paving project. During the
test, the height of the specimen is kept constant. To accomplish this, the vertical load actuator is controlled by
feedback from the vertical (axial) LVDT. The feedback to the horizontal (shear) load actuator is from the magnitude
of the shear load.
A1.3.3
Place the specimen inside the shear test device and clamp it securely in place.
A1.3.4 Adjust the controls for the environmental chamber to the requisite test
temperature and allow the chamber and the test assembly to stabilize at that temperature.
A1.3.5 Precondition the specimen for 100 cycles with a shear stress of 7 kPa. Each
cycle is 0.7 second in duration, and consists of the application of a 0.1 second haversine load
followed by a 0.6 second rest period.
A1.3.6 At the conclusion of the preconditioning, perform the repeated shear test for
a duration of 5000 load cycles or until the permanent accumulated strain reaches a level of
5 %. Apply a haversine shear load with a maximum shear stress level of 48 kPa. The axial
load is varied automatically during each cycle to maintain the specimen at constant height.
Each test cycle is 0.7 second in duration, and consists of the application of a 0.1 second
haversine load followed by a 0.6 second rest period.
A1.3.7 Record axial deformation, shear deformation, axial load, and shear load
during the test at the intervals shown in table 4 or at other appropriate intervals.
NOTEA1.3.--The test takes about 60 to 70 minutes to complete from the time the specimen is placed in the
apparatus until it is removed.
253