Micromechanical behavior of high performance concrete under cyclic loading at various moisture and thermal conditions

F. DEHN, ; M. SCHULTZ-CORNELIUS, ; A. CAGGIANO, ; E.A.B. KOENDERS; S. YANG, ; A. KÖNIG, ; M. PAHN, ; A. GILKA-BÖZOW, ; S. HARENBERG,

Conferencia; 89th Annual Scientific Conference - GAMM 2018; 2018

This paper provides preliminary results of a research study on the fatigue behavior of High-Performance Concrete. Resultsof an experimental campaign, performed at the Department of Concrete Structures and Structural Engineering of the TUKaiserslautern,is firstly proposed. The heterogeneous meso-structure and material degradation of HPC was studied throughcyclic bending-tensile tests. A test set-up were specially developed at the TU-Kaiserslautern to perform such activities.Particularly, different upper stress cycles (namely, cycle reversals) characterized by different force/stress amplitudes wereconsidered and analyzed. The influence of the edge zone on the stress cycles is tested on notched and normal specimenswhile the results are used for composing a so-called ?Wöhler curve? of the materials? fatigue behavior. Damage progressduring loading was monitored by means of a Digital Image Correlation system (DIC) and the results were used for improvingthe measurement accuracy. Based on these results, macroscopic and mesoscale simulations were performed at the TUDarmstadt?s Institute of Construction and Building Materials. A meso-mechanical approach for the numerical analysis ofHPC specimens subjected to low- and high-cycle fatigue actions will be presented. The possibilities of modeling the materialfracture response induced by fatigue is taken into account by means of a systematic use of zero-thickness interface elementsequipped with a fracture-based model and combined with a continuous damage constitutive law. A plastic-damage basedmodel for concrete subjected to cyclic loading is developed combining the concept of fracture-energy theories with a stiffnessdegradation, representing the key phenomenon occurring in concrete under cyclic responses. The experimental and numericalactivities proposed in this paper stem out from the DFG Priority Program 2020 Project "Cyclic Damage Processes in High-Performance Concretes in the Experimental Virtual Lab".