Published Online: 2 April 2009
Page Count: 8
Sevi, Adam F.
Assistant ProfessorFormerly, Ph.D. Student, Department of Civil Engineering, Norwich UniversityMissouri University of Science and Technology, NorthfieldRolla, VTMO
Assistant Professor, Department of Civil, Architectural, and Environmental Engineering, Missouri University of Science and Technology, Rolla, MO
Take, W. Andy
Assistant Professor, Department of Civil Engineering, Queen’s University, Kingston, ON
(Received 18 August 2008; accepted 4 February 2009)
Shear strength and compressibility of large grain-size materials are critical parameters for the geotechnical design of road bases, rock fill embankments, and railroad sub-base. However, due to the correspondingly large scale of triaxial specimens necessary for rock-fill and railroad ballast material testing, the numbers of facilities that are capable of testing these materials are few. In this paper, a cost effective design is documented for a triaxial apparatus capable of testing prototype railroad ballast material containing particle sizes up to 63.5 mm (2.5 in.). Unique to this testing apparatus is the use of vacuum as confinement to allow an unobstructed digital image measurement of specimen volume change during testing. The specimen preparation methodology, manufacture of latex membrane, and instrumentation are also discussed. Finally, the results of a cyclical triaxial test are presented to demonstrate the quality of the testing data from this triaxial apparatus.
Paper ID: GTJ102033