Modulus and Thickness Evaluation for Concrete Pavement by Love- and SH-Wave Measurements (05-2018)**
Sung-Ho Joh, Chung-Ang University, South Korea

Wave propagation techniques have been applied to make reliable measurements of the in situ conditions of Portland cement concrete pavements. The SASW method and the impact-echo method are typical techniques in this category. These methods, based on Rayleigh waves and P waves, respectively, may provide an evaluation of modulus and thickness of the concrete slab, but its accuracy and reliability is dependent upon the factors such as boundary conditions, measurement configuration and assumed Poisson¡¯s ratio. In this research, a new seismic technique is proposed and evaluated for the nondestructive evaluation of modulus and thickness of a concrete pavement. The proposed seismic technique is based on Love and SH waves, unlike the conventional seismic techniques based on Rayleigh and P waves. Love and SH waves are beneficial in that Love-wave velocity is equivalent to the shear-wave velocity of the surface layer and SH waves are not subject to mode conversion after multiple reflections. The proposed method is substantiated by the numerical simulation of the stress-wave propagation based on the forward modeling theory. Case studies are presented to verify the feasibility of the proposed approach. The SASW and the impact-echo testing were performed at the CRCP of the US highway 183 and US 59 in Texas. Love and SH waves were employed in the measurements together with Rayleigh and P waves for comparison. The resonance measurements of the cores taken from the pavement proved that the proposed method can evaluate modulus and thickness of the concrete slab reliably and accurately.