Evaluation of Concrete Cores Caruthersville Floodwall.

摘要

Core drilling followed by laboratory testing provided petrographic and physical data on the concrete from the Caruthersville Floodwall. The floodwall consisted of an old wall constructed before 1932 and a newer wall constructed in 1932. Concrete cores representing the old and newer concrete from various locations in the structure were tested to determine ultrasonic pulse velocity, compressive strength, and density. The petrographic examination indicated the presence of alkali-silica reaction product as isolated fillings the voids, coating some aggregate particles, and in some instances as coatings of cracked surfaces. No other deleterious chemical reaction product was identified in the concrete. The compressional wave velocities had an average value order 15,000 fps for the new concrete and over 14,500 fps for the old concrete. The average compressive strengths were 7630 psi for the new concrete and 3790 psi for the old concrete. One specimen of old concrete tested had a low ultrasonic pulse velocity of 10,970 fps, which correlated to a low compressive strength of 2,020 psi. Concrete densities were all consistently near 150 lb/cu ft. In general, the concrete appeared to be in acceptable condition. Only minor repairs involving monolith joints, isolated vertical cracks within monoliths, and areas of localized deteriorated concrete were recommended. (Author)