Use of acoustic emissions in flexural fatigue crack growth studies on concrete

The acoustic emission technique is used for monitoring the fatigue crack growth in plain concrete beams under three-point loading. Variable amplitude loading with step-wise increase in the maximum load is applied. The fatigue crack growth is continuously monitored using six acoustic sensors. The results of load, displacement, crack mouth opening displacement, acoustic events, and acoustic energy are simultaneously acquired during the test. It is seen that a Paris law type of relationship exists between the rate of increase of acoustic emission count per cycle and the stress intensity factor range. Using b-value analysis, different stages of fatigue fracture is explained.

► The AE technique is used to monitor the fatigue crack growth in plain concrete.
► The rate of crack growth is found to be independent of the specimen size.
► AE data can represent the amount of cracking and damage during fatigue loading.
► The AE rate is shown to have an explicit relation to the stress intensity range.