Nondestructive evaluation of in-place cement mortar compressive strength using spectral analysis of surface waves

This paper presents a modified experimental SASW method for nondestructive evaluation of the cement mortar compressive strength in in-place single-layer mortar slabs with a rather finite thickness. The tests were conducted on 3′ × 3′ × 4″ (91.44 × 91.44 × 10.16 cm) cement mortar slab specimens using steel balls as the impact source to generate surface waves at various frequencies. The boundary reflection effects were removed in this study by collecting only the wave forms before the time when the reflected compressive waves reach the receivers. The correlation between the surface wave velocity and the compressive strength was obtained by conducting the SASW tests at different ages of the slab specimens. The results can be applied to the quality control of early age concrete during the construction phase.