Investigating Effects of Low Temperature Change on Concrete Using Acoustic Emission Monitoring

Abstract

Concrete subjected to freeze- thaw cycles is one of the effects which deteriorate the concrete exposed to water in cold weather conditions. To evaluate the damages in concrete caused by freezing, it is necessary to understand the formation of ice in the pores. In this research, the performance of concrete exposed to freeze thaw cycles was monitored using acoustic emission techniques. The historical temperature data for Oklahoma City was analyzed for eleven years and the appropriate exposure regimen was selected. The concrete samples were subjected to freeze-thaw cycles with temperature varying between -6.4�C and 4�C and 60% RH. It was noticed that there were few AE event clusters recorded which did not follow any particular trend. More number of AE events are observed to be at the freezing and freezing hold phase which could be due to the water freezing in the voids and capillary pores. Hits are also observed to be in Thaw and thaw � hold phase, this can be attributed to the expansion of concrete. Most of the amplitudes and energies recorded were low; thus, indicating that significant damage may not have occurred.