Requirements for the choice of mortar and grouts for consolidation of three-leaf stone masonry walls

In this work, the experimental results on the application of natural hydraulic-lime based injections and repointing intervention techniques to three-leaf stone masonry walls are presented. Based on studies available in literature, a procedure for the choice of injection grouts, aimed at optimizing the walls injectability is proposed. The selection is firstly performed by checking the intrinsic rheological properties of grouts and then by controlling the injectability of masonry by injection tests on cylinders. Different particle-size distributions simulating the infill of multi-leaf stone masonry walls have been considered, as well as the influence of different additives in the grouts. The mechanical behaviour of the consolidated walls is discussed and an analytical formulation for the prediction of the compressive strength of injected walls is proposed for compatible low-strength grouts.