Mechanical behavior of two-leaf masonry wall-strengthening using different grouts

Abstract

Grout injection is an efficient method to improve the mechanical characteristics of masonry walls, in the presence of voids or cracks. Masonry made up of two exterior leaves with the space between them filled with poor infill with a large amount of voids is common in many existing structures. In other cases, dry stack masonry is used. Grouting of these types of vulnerable masonry with lime-based grouts was proven mechanically efficient. The success of this technique depends on several parameters, such as injection pressure, the general condition of the masonry (materials and mechanical properties), and the rheological properties of the grout. The effect of ternary grouts and hydraulic lime-based grouts on the compressive and shear strength of three-leaf stone masonry has been widely investigated. However, fewer studies have been done on walls with one or two leaves, as done in this paper. The present research aims to investigate the mechanical performance of schist masonry walls before and after injection. Six masonry walls of typical schist stone constructions from the north of Portugal were constructed in accordance with the original construction materials and tested under compressive load. Two different grouts were chosen to inject the wall specimens (one commercially available and another prescribed). The results obtained showed that these strengthening techniques were successful in increasing the compressive strength of the walls and improving their behavior under compressive loads.