Experimental Study On Constitutive Relation Of Concrete Under Stress And Combination Of Stress And Strain Loading Paths

Many mechanical properties about concrete under normal triaxial stress have been reported , including normal triaxial tests and true triaxial tests , but about mechanical behaviors investigation when concrete cubes were carried complex stress history is very scare , especially complex cyclic stress is fairy less . The thesis deals mainly with two kinds of special complex loading path experiments about concrete. One is normal true triaxial proportional monotonic and cyclic loading, the particularity is in all cyclic proportional loading proceedings, under both unloading and reloading are all with the initial proportion. The other is a very special triaxial experiment. First, hydrostatic stress was increased up to the value P, then the stress in one axis is constant, the deformation of second axis is also constant, and the stress in the third axis is monotonic and cyclic increased to failure. (Note: during the cyclic loading, unloading to the value P, and then reloading). The strength and deformation properties as well as stiffness degeneration were analyzed. In this investigation the results of the monotonic and cyclic loading tests were compared. Mechanical properties about concrete under the two special complex loading paths were obtained. Achievements from these are useful for developing concrete constitutive models under complex loading paths.