Three point bending beams with reinforcing bar placed at three different positions were used to study the influence of reinforcing steel on crack extension of concrete. A pair of forces F on the crack simu- s lates the constraint exerted…
Three point bending beams with reinforcing bar placed at three different positions were used to study the influence of reinforcing steel on crack extension of concrete. A pair of forces F on the crack simu- s lates the constraint exerted by steel. Cohesive force acted on the fictitious crack was considered. The whole process of crack propagation was analyzed combined with P−CMODcurves obtained from the test. The process of crack initiation, stable extension, and unstable failure was investigated using resistance strain gauges that were pasted on the center of the specimens. Therefore, the initial fracture toughness Kini and the Ic unstable fracture toughnessKun of reinforced concrete were introduced. Double-K fracture criterion was used Ic for describing the whole process of crack propagation of reinforced concrete three-point bending notched beams. The comparisons were made subsequently between the theory and test data, and the proposed theory agrees reasonably with experimental data.