A Determination of fracture toughness in plain concrete specimens by R curve

Abstract

Experimental tests and computational algorithm are implemented to investigate crack growth phenomena in C0.7 concrete. Firstly, three point bending tests are carried out on normalized prismatic specimens notched laterally (SENB), then, computational calculation was developed to calculate the concrete toughness on the basis of R-curve method. The R-curve was obtained from the curve connecting the crack mouth opening displacement (CMOD) to the applied load. During loading, elastic deformation followed by a significant plastic deformation were observed. Therefore, the crack growth in C0.7 concrete is defining by three stages: crack initiation, stable crack propagation and an unstable fracture. The average value of the critical stress intensity factor for the C0.7 concrete is 1.05 MPa.m 1/2 .

Fracture modelling of plain concrete using non-local fracture mechanics and a graph-based computational framework

“…The simulated contours of the average survival probability in the bending sample determined at the completion of the finite element simulation, drawn in the reference configuration, conducted ( b ) with rate effects and ( c ) without rate effects. Both simulations show that the ligament region is most prone to failure, and this agrees well with experimental data [56]. …”

“…The force-displacement response obtained from the FEM simulation of this boundary value problem using the material parameters listed in table 1 is also shown in figure 6, and we can clearly see that the experimentally determined force-displacement response is well-predicted by the force-displacement response obtained from the FEM simulation. Moreover, the simulated contours of average survival probability in the sample at the end of the FEM simulation (see figure 6) also show that the most damage prone area in the sample is the region, which immediately encompasses the ligament edge, and this agrees well with experimental data [56] and also results determined from phase field simulations [21].…”

“…A very popular experimental setup to study failure of plain concrete under bending is the symmetrical three-point bend test of an initially notched specimen [51]. For this experiment (where the sample experiences a multi-axial stress state), the crack typically grows from the notch towards the loading roller, that is, the growing crack will be located directly under the loading roller [56].…”