Mesoscopic simulations on the strength and size effect of concrete under biaxial loading

In practical engineering, most concrete structures are in complex stress states. The lateral stress ratio presents significant influences on the mechanical properties of concrete under multiaxial stress. In this study, a 3D mesoscopic modelling approach was established to simulate the mechanical behavior of concrete specimens having different sizes under quasi-static biaxial compression (C-C case) and biaxial compression-tension (C-T case) at different lateral stress ratios lambda (lambda = 0, +/- 0.25, +/- 0.5, +/- 0.75, +/- 1, and infinity). The influences of the lateral stress ratio on the failure mode, the nominal spindle compressive strength, nominal lateral tensile strength (only under C-T case) and the corresponding size effect were investigated. The results indicate that the spindle compressive strength first increases and then decreases for the C-C case. The corresponding size effect is gradually weakened and then strengthened as the lateral stress ratio increases. While for the C-T case, with the increase of the lateral stress ratio, the spindle compressive strength gradually decreases and the corresponding size effect gradually increases. Correspondingly, the lateral tensile strength gradually decreases and the corresponding size effect gradually increases by the increasing spindle compressive stress.

Automated summary

The study investigated the influence of lateral stress ratio on the mechanical properties of concrete specimens under different loading conditions. It was found that the spindle compressive strength and lateral tensile strength exhibited different trends with the increase of lateral stress ratio in different scenarios.