Evaluation of consolidation of grout injection with ultrasonic tomography

Old masonries especially in the case of multi-leaf walls often present low compactness and very few links between the internal and external leaves. The injection of grouts in the core of the multi-leaf masonries is one of the techniques used most frequently for consolidation. In order to test the effectiveness of the filling process and the bonding of the grout to the masonry materials, ultrasonic tomography was conducted complemented with mechanical tests. The mechanical results showed good correlation with ultrasonic results and density gradients along the porous medium injected were obtained. Moreover, it was confirmed the importance of the bond properties of the interfaces (grout – porous medium particles) on the mechanical results. Regarding the ultrasonic tomography, the research demonstrated a correspondence between the characteristics of the porous media after the injection and the information displayed in the tomographs. Thus, it is proved that ultrasonic tomography is a useful technique to evaluate effectiveness of the grout injections, allowing an understanding of the ability of the injections to modify the physical and mechanical properties of an injected porous medium. This research has special relevance due to lack of information about the study of grout injection capacity in physical models (simulating the old masonries), through tomography and mechanical tests when compared to the amount of information that already exists in the case of study of grout injectability tests.