Combining Ultrasonic Pulse Velocity and Nonlinear Ultrasonic Techniques to Assess Concrete Strength

Abstract

Nonlinear ultrasonics (NLU) has grown in importance over the past years. The viability of applying the newly developed NLU technique called the Sideband Peak Count-Index (SPC-I) to estimate the 28-day unconfined compressive strength (UCS) of cylindrical concrete specimens is investigated. In addition, the SPC-I technique is combined with the conventional ultrasonic pulse velocity (UPV) technique to achieve more precise UCS estimations than would be possible with a single estimation parameter. Sixteen conventional general-purpose concrete specimens are cast utilizing water-to-cement (W/C) ratios of 0.4, 0.5, 0.55, and 0.6. To ensure the reproducibility of results, experimental operations are performed utilizing consistent testing protocols and instruments. The SPC-I is determined to be a viable parameter that can be used to estimate the UCS value of concrete specimens with high accuracy. In addition, when the SPC-I is combined with the UPV, the resulting estimates become even more accurate and reliable than when utilizing only UPV values.