Old masonry buildings, either current or culturally relevant, are the most relevant types in many cities. They frequently are in a bad conservation condition, thus requiring interventions that usually differ from those used in modern buildings.

Injection grouts are one of the most widely used techniques for masonry consolidation. Grouts for injection should be well conceived, taking into account the optimization of their performance.

The aims of the project were to fill the lack of information about the influence of different organic and inorganic additives in natural hydraulic lime grouts, particularly in what concerns rheology, stability, strength, durability and modes of action in grouts. The efficiency of grouts depends mainly on the injectability properties, rather than the simple mechanic characteristics of the hardened mixtures. This means that the rheological behaviour is crucial, so in this project it was established a strong relationship between rheology and injectability of grouts. The evaluation of the grout injectability was carried out on reduced scale masonry models and using the technology of ultrasonic tomography it was possible to evaluate the compactness of the consolidation. In addition those reduced models were also used for mechanical strength evaluation. Combining the information that was collected it allowed a better knowledge about the design of grouts as well as about the adequate conditions for their application.

The research undertaken in this project tries to act at all levels to improve the performance of injection grouts and to contribute to a better knowledge about the design of grouts as well as about the adequate conditions for their application.

Our research team is composed by several PhD researchers (from Civil Engineer Department, CENIMAT and REQUINTE) with a strong background in this area. The researchers from the Civil Engineering Department are experts in masonry performance, grout injection and design, based in principles such as mechanical characteristics and durability and have a strong background in experimental techniques; the researcher from CENIMAT is expert in rheology determination and interpretation; the researcher from REQUIMTE is an expert in Nuclear Magnetic Resonance applied to material flow in porous media and member of the Laboratory of Magnetic Resonance in Heterogeneous Materials of FCT/UNL.