The strengthening of stone masonry walls with grouting.

The influence of compressive strength of the grout on the seismic behaviour of stone-masonry walls has been investigated. 8 specimens injected with 4 different types of mixes with different compressive strength have been tested by subjecting them to constant vertical and cyclycly acting horizontal load. Although the values of the compressive strength of the grout varied from 6.8 to 32.5 MPa, no significant difference in the behaviour of the tested specimens has been observed. The wide range of values of compressive strength of the grout did not influence the shear strength of stone-masonry walls. This will make easier the development of mixes designed for special purposes, which often have additives which significantly reduce their compressive strength.