Dynamic compression failure mechanisms in homogeneous mortar and three-dimensional mesoscopic concrete: a comparative study using the split Hopkinson pressure bar

Abstract

At the mesoscale, concrete is recognized as a three-phase composite comprising aggregates, mortar, and the interfacial transition zone. Despite mortar’s critical role in concrete’s mechanical behavior, its properties are frequently approximated by simply scaling down those of concrete without rigorous calibration. This approximation hinders a precise understanding of mortar’s contribution to the overall mechanical response and failure mechanisms of concrete. To address this, both quasi-static and dynamic compression tests were conducted to characterize the stress–strain responses and failure patterns of mortar specimens and to establish a quantitative characterization of strain-rate sensitivity. Complementary numerical simulations were performed with a modified Karagozian & Case model calibrated by experimental findings. Comparative analyses were conducted to elucidate distinct differences in failure behaviors between mortar and concrete under dynamic compressive loading. The results revealed that while concrete exhibits greater compressive strength, mortar demonstrates a more pronounced strain-rate effect. This study provides new insights into the dynamic failure behavior of cementitious materials and advances the modeling and safety assessment of concrete structures under impact or blast loading.

Graphical abstract