Experimental studies of the effectiveness of masonry reinforcement by mortar injection

Introduction. Pressure injection of masonry is one of the most effective methods for restoring its integrity in areas with cracks, delamination, repairs, and joints between dissimilar masonry. This injection method is especially valuable for historic buildings.

Aim. To obtain experimental data on the strength and deformations of masonry reinforced by pressure injection of mortar.

Materials and methods. Tests were conducted on specimens reinforced with mortar injection, including those with structural reinforcement, under uniformly distributed loads and localized compression, using historical and modern solid brick in the form of pillars and walls, constructed with mortars of varying strengths. The combined performance of reinforced masonry in repair sections with filler and specimens in which the inner layer (backfill) differed in strength and deformation from the facing layers was studied.

Results. Strengthening coefficients for masonry reinforced by pressure injection were obtained. The research results were used in the development of regulatory documents for masonry structures and recommendations and projects for strengthening masonry structures, including historic buildings.

Conclusions. In cases of multiple cracks in masonry spaced 10–25 cm apart, it is possible to increase the load-bearing capacity of the masonry. The effectiveness of reinforcement increases for masonry constructed with weak mortars. The best results are achieved with epoxy resin injection. The use of cement mortars with hydraulic lime allows for the restoration of the integrity of masonry in historic buildings. A combination of injection reinforcement and indirect reinforcement using drilled holes in the masonry produces significant results.

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