Engineering properties of lightweight aggregate concrete assessed by stress wave propagation methods

This study investigates the variation of engineering properties and wave velocities of two kinds of lightweight aggregate concretes by non-destructive stress wave propagating testing methods. Both cylindrical specimens and plate specimens at ages of 7, 14, 28 and 56 days were studied. Experimental results show that, at ages from 7 to 56 days, the average strengths and moduli of elasticity of concrete cylinders increase by 25–37%, while the average ultrasonic pulse velocities increase only by 5–7%. The dynamic moduli of elasticity of concrete cylinders are higher than the static moduli of elasticity by about 41% in average, and both have a very close correlation with their corresponding ultrasonic pulse velocities. P-wave velocities across the section of concrete plates from the top to the bottom faces vary about 14–15% by linear extrapolation. Except for the concrete plate at age of 7 days, P-wave velocities measured at the top face of concrete plate by one-sided velocity method are smaller than those by impact-echo method by 2–5%.