Influence of Laboratory Compaction Methods on Shear Performance of Graded Crushed Stone

This paper presented a study on the effects of two laboratory compaction methods, namely, vibrating compaction and modified proctor compaction on the stress-strain characteristics and shear strength of graded crushed stone. The triaxial shear test results showed that samples made by vibrating compaction possessed higher modulus of rupture, higher initial modulus of elasticity, and lower failure strain values as compared with samples made by the modified proctor compaction. Specifically, the values of cohesion and angle of friction of the samples made by the vibrating compaction increased by 38% and 2 degrees respectively as compared with the samples made by the modified proctor compaction. Also, the shear strength associated with vibrating compaction increased by 20% as compared with the modified proctor compaction case. The main factor contributing to these differences was that the vibrating compaction generated a better distribution of particle orientation angles than the modified proctor compaction. Therefore, in the construction of graded-crushed stone base, it is recommended that primarily a vibrating roller be used for compaction.