Electromagnetic scattering applied to the non destructive evaluation of mortar and grout injections

A new system for the diagnosis of the grout injections is proposed in this paper. The system allows to find the effective and homogenous diffusion of the grout injected in masonries and other similar structures, interested by renovation and consolidation actions. The basic working principle is based on the detection of the modification of the electromagnetic characteristics at different depth inside the masonry, mainly due to the presence of grout injection. The set-up and the calibration of the detection system have been performed by means of a dedicated theory and laboratory tests, using brick walls and other special grout elements, also mixed with metallic powders, in order to enhance the detection sensibility. On-site experimental tests have been carried out on ancient stone masonry walls, and the recorded data, suitably processed by dedicated inversion digital codes, have been verified by inspection, in order to highlight the effectiveness and the reliability of the proposed system.