Experimental study of resilient modulus of unsaturated soil at different temperatures

Fatigue cracking and failure in asphalt and concrete layer of a road pavement are of great concerns to pavement designers and users. The deformation of this layer is related to resilient modulus (MR) of subgrade soil under cyclic traffic loads. In the field, subgrade soil is subjected to daily and seasonal variations of soil suction and temperature. Although thermo-hydromechanical behaviour of soil has attracted intense attention, suction and thermal effects on MR under cyclic loading-unloading have rarely been reported. In this study, three series of cyclic triaxial tests have been carried out to investigate MR of an unsaturated silt at different temperatures in a newly developed suction and temperature controlled cyclic triaxial apparatus. The new apparatus is employed to investigate MR of the unsaturated silt at six different suctions (0, 30, 60, 100, 150 and 250 kPa) and two different temperatures (20 and 40 ). To enhance the accuracy of strain measurements, Hall-effect transducers are adopted to measure the local axial and radial deformations of each specimen. The influence of suction and temperature on MR are presented and discussed.