CONCRETE OVER THE TOP, OR IS THERE LIFE AFTER PEAK?

Test results are presented that show the postpack response of concretes of 3 different strengths under triaxial stress states. These test results clearly show the transition from brittle to ductile behavior under increasing confinement, the residual strength, and the strain behavior at and after peak. Some evidence that indicates that Drucker's postulate may be relaxed for concrete is presented also. Concrete of different strengths behave similarly, with increasing brittleness for higher strength concretes.