Reduction of compressive strength of concrete due to triaxial compressive loading history

One of the major technical interests for concrete is the damage mechanism under various loading patterns. In this paper the influence of monotonic and cyclic triaxial compressive loading histories upon the compressive strength of concrete cubes is studied experimentally. The maximum axial strain experienced by the cube associated with lateral confining pressure is defined as the loading history. The reduction of compressive strength characterises the degree of damage of these cubes. The laws of damage initiation and development of concrete under the condition of varied confinement pressure are investigated. Based on the results of curve-fitting of experimental data, the evolution equation of damage is obtained. The main factors affecting the damage development are examined and the causes are analysed. It is demonstrated that the method is convenient and applicable to estimation of the damage of concrete in engineering practice.