The effects of age and water/cement ratio upon the relation between ultrasonic pulse velocity and compressive strength of concrete

Abstract

Summary Experiments have been made on concretes with varying aggregate/cement and water/cement ratios, with the main object of ascertaining the effects of changes in age and water/cement ratio upon the relation between ultrasonic pulse velocity and the compressive strength of concrete. It was found that the ratio of changes in pulse velocity and compressive strength due to a change in water/cement ratio is not generally the same as that due to a change in age. Because of this, the relation between pulse velocity and compressive strength cannot be expected to be independent of age and water/cement ratio. It appears, however, that, for compressive strengths up to about 4,000 lb/in², the relation may for practical purposes be regarded as being so. For concrete of the same aggregate)cement ratio, it was found that low pulse velocity at an early age predicts low strength at later ages.