Failure of concrete under sustained tension

Abstract

Synopsis The mechanism of cracking in concrete under sustained axial tension is investigated experimentally. This involves the development of new loading and measuring techniques: in particular, the development of a specimen with shoulder-pieces composed of high alumina cement concrete which permits the direct transmission of ultrasonic pulses along the longitudinal axis. Observations indicate that cracks form in the concrete at an early stage of loading at interfaces between the cement matrix and aggregate but that failure is governed by the growth of cracks within the cement matrix. The results are used to establish a law relating sustained stress to time to rupture, which may prove to be of value in analysing the behaviour of more complex structures under sustained load.