Analysis of time dependent cohesive laws for high and normal strength concretes based on Sequentially Linear Analysis (SLA)

Abstract In earlier research it was found that the fracture energy can be obtained from incomplete load-opening curves utilizing Sequentially Linear Analysis (SLA) (Czernuschka et al., 2018; Vorel et al., 2019). This method has the advantage that the traction-separation diagram (TS) becomes accessible without prior assumptions concerning its shape, which is an important feature for the evaluation of the fracture behavior. This contribution employs the introduced SLA to study the evolution of fracture properties with age based on notched three-point bending tests. The results confirm that the TS-diagrams can be approximated by a bilinear or trilinear softening law. Furthermore, the tensile characteristic length, as defined by Hillerborg et al. (1976), is chosen for the description of aging fracture properties.