Repair of earth masonry by means of grouting: importance of clay in the rheology of a mud grout

Abstract

Building with earth is one of the most ancient and traditional ways of building. Consequently, many historic and new-built earthen buildings can be found all over the world. However, the specific characteristics of earthen materials make the earth constructions very sensitive to external damaging agents. In particular, the weakness and fragility extensively recognized on earthen materials make this type of constructions very vulnerable from a structural perspective. In general, the structural damage on earth constructions occurs in the form of cracks, which debilitate the structural behaviour and compromise the durability. Injection of mud grouts can be seen as a reliable and economic solution for repairing earth constructions. The success of such intervention on a historical construction requires following an appropriated design methodology. However, the knowledge about mud grouts is still limited, and thus research efforts are needed in order to develop such methodology and to surpass many of the difficulties that the restorers of earth constructions are currently facing. Understanding the rheology of the mud grouts is one of the key issues of the all process. Hence, this paper explains an initial proposal of methodology for the design of mud grouts and an experimental campaign that aimed to understand the role of the clay fraction in the rheology of mud grouts.