Manager, Soils and Pavements Division, Civil Engineering Research Facility, University of New Mexico, Campus Post Office, Albuquerque, N. Mex.
ConsultantMember of ASTM, Civil Engineering Research Facility, Ventura, Calif.
When a specimen of engineering material is subjected to external loads, stress waves known as acoustic emissions are induced. A unique characteristic of many engineering materials that emit acoustical energy is that upon reloading the specimen does not emit acoustical energy until the magnitude of loading exceeds the prior maximum loading. This investigation was undertaken to determine if this characteristic could be used to disclose the loading history of plain portland cement concrete. The test results show that the unique characteristic is very temporary and therefore cannot be used to determine the prior maximum loading on a concrete specimen. Within a matter of hours concrete subjected to loading within its elastic limit recovers, and acoustical energy may again be released by reloading.
Paper ID: JTE10561J