Experimental investigations were carried out to study the effects of triaxial stress on
concrete. Concrete of 4 different strength levels were employed and triaxal tests were
performed on 100 x 300 mm cylindrical specimens to establish the failure criteria for
low, normal and high-strength concrete. The effects of confining pressure and stress
path on different grades of concrete were also studied and test results were used to
verify the failure criteria proposed by other researchers.