Abstract
The method of determining concrete fracture energy recommended by RILEM has an obvious size effect, so determining fracture energy that is unaffected by size of the test specimen is difficult. In this study, 60 high-strength concrete single-edge notched beams (SENBs) of different sizes, crack length-to-depth ratios, and span-to-depth ratios were subjected to the three-point loading test as recommended by RILEM. Then, the influences of the boundary effect on the fracture energy were identified. Based on the SENB boundary effect model, a piecewise function of the interrelationships between the experimental test fracture energy Gf, the local fracture energy gf, and the fracture energy unaffected by specimen size GF was established. The applicability of the boundary effect model was verified using the test results from this study and from the previously published research. The results show that the local fracture energy distribution in the boundary influence region was nonuniform. The smaller the local fracture energy was, the closer it was to the rear boundary of the specimen. The influence length al∗ of the boundary increased with the increasing specimen size. Based on the bilinear distribution model of the local fracture energy gf, the fracture energy unaffected by beam size GF can be obtained according to the fracture energy Gf measured for laboratory-scale small-sized SENB specimens. Furthermore, the model predictions are in good agreement with experimental observations.
Highlights
Fracture energy is an important fracture property parameter of concrete and can directly reflect the crack resistance of this material [1,2,3,4]. eoretically, the best method for determining the fracture energy of concrete is the direct tension test
It was found that the self-weight of the three-point load on an single-edge notched beams (SENBs) has a great influence on the results, and the fracture energy determined from different sizes of specimens exhibits a significant size effect
A method for determining the fracture energy unaffected by specimen size GF was established using laboratory-scale small-sized SENB specimens. e major conclusions are summarized as follows: (1) e fracture energy Gf measured by the SENB three-point loading test decreases as the ligament length (W − a) decreases, and the two measures are linearly correlated
Summary
Fracture energy is an important fracture property parameter of concrete and can directly reflect the crack resistance of this material [1,2,3,4]. eoretically, the best method for determining the fracture energy of concrete is the direct tension test. RILEM recommended using a simple three-point load on single-edge notched beams (SENBs) to determine the fracture energy of concrete [5]. It was found that the self-weight of the three-point load on an SENB has a great influence on the results, and the fracture energy determined from different sizes of specimens exhibits a significant size effect. E cited research shows that the fracture energy Gf determined using the RILEM-recommended three-point loading test of concrete SENB changes with the size of the specimen. The three-point loading of concrete SENB recommended by RILEM was used to determine the fracture energy of high-strength concrete SENBs of different sizes, span-to-depth ratios, and crack length-to-depth ratios. E applicability of the model was proved, and a method for analyzing the fracture energy unaffected by specimen size GF was established using laboratory-scale small-sized SENB specimens Based on the SENB boundary effect model, the relationship between experimental test fracture energy Gf , local fracture energy gf , and fracture energy unaffected by specimen size GF was obtained. e applicability of the model was proved, and a method for analyzing the fracture energy unaffected by specimen size GF was established using laboratory-scale small-sized SENB specimens
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
