Field Soniscope Tests of Concrete. Report 3, Ten-Year Summary of Results

摘要

During the period 1953-1963, soniscope measurements of ultrasonic pulse velocity were made at several test stations in the concrete portions of four dams (Clark Hill, Wolf Creek, Bull Shoals, and Norfork) and one lock (Tuscaloosa), and on 92 concrete specimens at a Portland Cement Association field exposure station. These measurements are used for evaluating changes that have taken place in the concrete and for the long-range evaluation of the soniscope as a device for non-destructive testing of concrete structures. Both at the lock and at the four dams, some stations showed velocity increases, some decreases, and some no significant changes. At three of the four dams, velocity measurements taken along monolith surfaces were generally inconsistent and indicate that measurements of this type taken over long paths are not reproducible and probably not reliable. Results of other investigations show that reliable surface measurements, taken along shorter paths, are not necessarily indicative of the quality of the interior concrete. Excellent reproducibility was obtained with velocity measurements on the 92 concrete specimens at the Portland Cement Association exposure station. The results of this investigation, supplemented by information obtained from other studies, indicate that the soniscope is an effective instrument for detecting inferior or damaged concrete in structures. The velocity comparison method, supplemented by empirical correlations, provides data that can be used for locating defective areas, making approximations of concrete strength, and checking the state of repair in concrete structures. (Author)