Application of Fracture Mechanics to Flexural Failure Behavior of Concrete

点击翻译按钮获取中文摘要

Fracture mechanics concepts such as tension softening diagrams are applied to investigate the flexural failure behavior of concrete and reinforced concrete beams. The following topics are dealt with in this study. 1. Effects of specimen size and cross-sectional shape on flexural strength of concrete. 2. Determination of fracture energy and flexural strength by means of bend-off tests. 3. Flexural failure behavior of steel fiber reinforced concrete beams. 4. Flexural failure behavior of lightly reinforced concrete beams.The following results are obtained from experiments and numerical analysis. 1. Results of experiments and analysis indicate that the flexural strength of concrete beams decrease as the specimen depth increases. 2. An equation to estimate the flexural strength of concrete beams with different depths is proposed. 3. It is seen from experiments and analysis that the flexural strength of concrete beams with circular cross-section is larger than that of beams with square cross-section due to the contribution of the tension softening. 4. The effects of steel fiber reinforcement is more remarkable for larger beams. 5. The tension softening properties of concrete are taken into account in equations to estimate the cracking load and yielding load of lightly reinforced concrete beams. 6. It is shown that the deformation on the descending branch of load-displacement curves tends to localize whereas it tends to spread before the peak load.