Abstract This paper shows the complementarity of two nonlinear ultrasonic imaging methods to characterize closed macro cracks in concrete. A time reversal mirror is used locally probe and image nonlinearity a cracked region. Two parameters are extracted map The obtained using first parameter relates harmonic generation due contact frictional behaviors at crack lips, correlated with vibro-thermo...

This paper presents a numerical modelling study on the simulation of the cracking process and fracture energy in concrete under high strain rate. To capture the stress wave effect and the damage evolution at the meso-length scale, both a homogeneous model with a millimetreresolution mesh and an explicit heterogeneous mesoscale model with random polygon aggregates are employed. The tendency of d...

The J-based fracture testing technique is newly extended to experimentally determine the tension-softening (a-6) relations in ceramic-matrix composites. The J-based technique originally proposed for concrete has been well established for quasi-brittle materials where the fracture process is primarily dominated by the formation of a fracture process zone and the contribution of the crack tip tou...

This paper presents two shear tests of -in. diameter cast-in anchors embedded in the plastic hinge zone of reinforced concrete columns. Design codes, such as ACI 318-14, require special reinforcement for concrete anchors in concrete that could be substantially damaged during an earthquake. The test anchors in this study were equipped with the anchor reinforcement recommended and verified in the...

Abstract This paper presents experimental verification of indirect tests for the determination stress-crack opening curve concrete, based on method described in RILEM TC 187-SOC report and submitted to ACI Committee 446 Fracture Toughness Testing Concrete, which relies standard cohesive model. In such method, a bilinear approximation softening is determined from three-point bending notched spec...

Except for huge unreinforced structures, Weibull’s statistical size effect is weak in concrete structures. The size effect source is principally energetic, caused by stress redistribution due to a large fracture process zone size or large cracks formed before maximum load. It is shown that an unbiased statistical analysis of the existing database for shear of R.C. beams without stirrups support...

Tension stiffening behavior of post-cracking concrete is an important phenomenon which has been extensively studied for reinforced concrete structures. Although externally bonded fibre reinforced polymer (FRP) composites are widely used for strengthening existing RC structures, it remains unclear to what extent the tension stiffening of post-cracking concrete is quantitatively influenced by the...

Concrete is a quasi-brittle building material that has low tensile strength. The process of its destruction under loading inhomogeneous, due to the nature concrete structure mass, consisting components with different physical and mechanical properties. Gradual deformation can be characterized as formation development microcracks. presence different-sized in makes it possible consider multi-leve...