Characterization of Early Stage Concrete by Non-destructive Testing

Abstract

To non-destructively assess the behaviors of early stage concrete, seismic methods are useful tools. These methods also aid in learning about curing concrete for use in construction decisions. This paper discusses how freezing concrete causes a major change in the engineering properties. In the experimental procedure, ultrasonic tests were conducted on curing concrete subjected to different freezing process. The experimental procedures involved performing ultrasonic tests on concrete frozen in various ways. The results showed that there exists linear correlation between low strain seismic wave velocity and concrete strength under normal curing conditions. However, these relationships do not hold if the concrete is subjected to freezing process. To correct for the frozen effect, the bulk modulus needed to be adjusted. With the correction, a linear relationship with water content was found. Procedures to correct the effects of freezing are proposed, which include the use of Time Domain Reflectometry to measure the water content. Time Domain Reflectometry can be used to measure water content and help to correct the effects of freezing. This process allows an estimate for the strength of the frozen concrete. This information could be incorporated to determine the magnitude of Winter Load Increase in cold regions for government agencies.