New Method for Investigating Crack Development in Concrete Using an Ultrahigh-Speed Camera

Abstract

Cracks are ubiquitous in concrete materials and can destabilize a concrete structure, regardless of size or type. This study focuses on the cracking behavior of main and branching cracks in concrete. Compression tests and an ultrahigh-speed camera are utilized to capture the crack formation. Crack length and cracking speed under a compressive load are measured and calculated. An accurate method for measuring crack characteristics is presented. Results show that the length–time and developing speed–time curves of the branching crack exhibit an evident fluctuation compared with that of the main crack. The main crack maintained a relatively stable crack development speed during the entire loading process. This relatively stable speed may result from the development of the branching crack. If the concrete is damaged, then the branching crack can delay the cracking speed of the main crack and minimize damage.