Shear behaviour of rammed earth walls repaired by means of grouting

Southern Portugal presents a rich heritage constituted by several constructions made from unstabilised rammed earth (URE), which are threatened by several factors, ranging from lack of conservation to a non-negligible seismic hazard. These threatens are enhanced by the fact that little is known about the shear behaviour of URE constructions. The preservation of this heritage requires definitely the development of this knowledge and, in addition, the development of adequate intervention solutions. This paper presents an experimental program where the shear behaviour of URE is assessed by means of diagonal compression tests on representative wallet-specimens. Furthermore, the use of mud grouts in repairing cracks was also assessed. The results showed that the shear behaviour of URE depends on the binding capacity promoted by the clay fraction and on the friction and interlocking promoted by the coarse aggregates. The repair by injection was shown to promote satisfactory shear strength recovery of the specimens, but was less effective in recovering the initial shear stiffness.