Repair of Earth Constructions by Means of Grout Injection (Herstel van aarden constructies door injectie)

Nowadays, one fourth of the World s population lives in a house made from earth. Consequently, there is a large built stock widely distributed around the World going much beyond simple dwellings. An important part of the earth built stock is found often affected by cracking, whose repair is fundamental for the reestablishment of the structural integrity. However, the successful cracking repair of earthen walls requires employing adequate intervention techniques. With this respect, the injection of mud grouts is being put forward in the recent years and has been showing good results in the few reported cases. This thesis aims at contributing to the development of the limited knowledge on the injection technique applied to earth constructions. The broad extension of this topic led to selecting the injection of unmodified mud grouts (without mineral binders) in rammed earth constructions as case study. This thesis also intends contributing for the characterization of the rammed earth construction from southern Portugal and for the numerical simulation of its behaviour. An experimental program was defined and included the execution of a composition study about the behaviour of unmodified mud grouts, involving several variables of their composition and the characterization of important properties governing the injection technique. The design of a mud grout has shown to require accounting for both the limitation of the clay content and the effect of the addition of a deflocculant.The experimental program continued with the suitability assessment of four soils from Alentejo (Portugal) for unstabilised rammed earth construction, and the selection of a representative soil used to manufacture medium- and large-scale rammed earth specimens. These specimens were used to assess the repair effectiveness of three different unmodified mud grouts. The results indicated that the injection of mud grouts is capable of attaining adequate repair effectiveness, providing that the same soil used in the construction is incorporated in the grout composition.Finally, the shear behaviour of rammed earth wallets tested under diagonal-compression was modelled resorting to the finite element method, where both the macro- and micro-modelling approaches were used. Both cases provided an adequate simulation of the non-linear shear behaviour, being highlighted the enhanced shear ductility of rammed earth.status: publishe