Determination of fracture energy and fracture toughness of two types of concrete and their interface

Abstract

In this study, three-point bending tests are performed on high-strength concrete, low-strength concrete, cementation of high and low-strength concrete with interface between them and interface reinforced by steel fibre, respectively. The corresponding crack initiation load, peak load, external works at several loading points, fracture energy, pre-failure damage characteristics and double-K fracture toughness parameters are analysed based on test data utilising the theory of fracture mechanics. The quantitative comparisons of these values are made for different types of specimens. It reveals that the interface causes a great reduction on crack initiation load, peak load, the fracture energy, initiation fracture toughness and unstable fracture toughness. The pre-failure process of specimens with interface develops faster than other intact specimens. In addition, the steel fibre can reinforce the interface, especially, in increasing the sustainability at the post failure stage.

Keywords:

• Concrete
• interface
• fibre-reinforced interface
• fracture energy
• double-K fracture toughness

Acknowledgement

The constructive comments by anonymous reviewers are appreciated.

Disclosure Statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Science Foundation of China [grant number 51608537], [grant number 51538009], [grant number 11402311]; China Postdoctoral Science Foundation [grant number 2017M610508]; and Postdoctoral Foundation of Central South University.