抄録
The impact-eco method is a nondestructive evaluation for defects in concrete structures analyzing elastic wave due to a mechanical impact. Cracks and voids are commonly repaired by injection of grout material. Impact-echo method might provide information of repair effectiveness of injection of grout material. In order to evaluate the effect of grout material on reflected waves and frequency spectra, impact-echo method is applied to repaired concrete structure and specimen. As a result, the followings are found: spectral peak of defects disappeared after injection of grout material; and spectral amplitude of defects decreased and disappeared with increasing of acoustic impedance of grout material.
