The Use of Surface Waves to Estimate In-Place Strength of Concrete

Abstract

Non-destructive evaluation (NDE) techniques are needed to evaluate in-place strength of concrete in structures. Often mechanical wave propagation parameters are used to establish a correlation with strength. P-wave velocity measurements are most common for this purpose, but its application can be problematic. Here the utility of surface waves is investigated. Surface wave velocity and transmission (attenuation) properties are considered, where a self-compensating approach overcomes experimental difficulties usually experienced in transmission measurements. In this paper, the testing configuration is described and the concept of the self-compensating approach introduced. Then a test series is described: surface wave velocity and wave transmission and P-wave through thickness velocity data are collected from concrete slabs of different strengths. Relations between concrete strength, wave velocity and surface wave transmission are established. Surface wave velocity and normalized surface wave velocity data correlate well with in-place strength. Transmission data also are sensitive to concrete strength but data variation must be improved.

Evaluation of Early-Age Concrete Compressive Strength with Ultrasonic Sensors

“…To further examine the relationship between the surface wave velocity and concrete strength at an early age, the measurement data for hardened concrete from previous studies [ 18 , 19 , 20 ], as shown in Figure 10 , are superposed in Figure 9 . Shin et al [ 18 ] considered concrete at an age of 2–28 days.…”

“…Popovics et al [ 19 ] adopted a curing age of 24 h–28 days. Gallo and Popovics [ 20 ] provided surface wave velocities for concrete aged for 7, 14, and 28 days. Figure 9 shows that the relationship between the compressive strength and surface wave velocity of early-age concrete within 24 h is consistent with that of hardened concrete obtained from previous studies using Rayleigh waves.…”

“…Stress waves are generated when pressure is induced by ultrasonic sensors attached to a concrete surface. Rayleigh waves have been adopted by many researchers for nondestructive testing purposes [ 18 , 19 , 20 , 21 ]. When generated in concrete, Rayleigh waves propagate along the free surface of the concrete.…”

“…Surface wave-based methods have been investigated because they only need access to one side [ 16 , 17 ]. Research on the relationship between the surface wave velocity and concrete strength has focused on hardened concrete [ 18 , 19 , 20 , 21 ]. This study investigates the feasibility of using surface wave velocities to predict the strength of in situ concrete inside the form at a very early stage and the correlation between the surface wave velocity and concrete strength.…”

Experimental Validation of Slip-Forming Using Ultrasonic Sensors

“…In recognition of this need, various nondestructive evaluation methods, such as embedded piezoelectric transducers [6,7,8] and electro-mechanical impedance methods [9,10,11], have been developed to monitor the early-age strength of concrete during construction. In particular, the ultrasonic wave velocity method, which uses surface waves among various wave components, has been demonstrated to be effective for evaluating the hardening of concrete with various levels of embedment [12,13,14,15].…”