Experimental and Numerical Characterization of High-Strength Concrete Under Monotonic and Fatigue Mode II Loading with Active Control of Lateral Compression

Abstract

Fatigue of plain concrete has been extensively researched for many years. Traditionally, investigations have focused mainly on compressive or tensile loading and little attention has been paid to shear loading (mode II). However, this type of loading has the advantage of providing precise load determination and a small, well-defined fracture surface, resulting in low scatter and good reproducibility. Exploiting these advantages, a comprehensive experimental campaign was conducted to systematically investigate the monotonic, cyclic, and fatigue response of high-strength concrete under mode II loading with actively controlled level of lateral compression, using newly adapted punch through shear tests (PTST). For a deeper insight into the stress development and fracture process under fatigue loading, numerical studies characterizing the experimental results will be presented. To enable an efficient and realistic representation of the pressure-sensitive, shear-dominated fatigue response, the PTST is axisymmetrically idealized, modeling the shear surface using the fatigue microplane model MS1. In this model, the tangential damage is linked to the cumulative inelastic shear strain to reflect the accumulation of fatigue damage owing to internal sliding between aggregates. The model aims to capture the basic inelastic mechanisms that are driving the tri-axial stress redistribution within the material zone during the fatigue damage process in concrete. First calculations show good agreement with experiments and indicate great potential for a more detailed investigation of the dissipative mechanisms occurring in the shear surface.