Department of Civil Engineering, Universidade Nova de Lisboa


The purpose of a grout injection technique applied in a multiple leaf wall is to increase the compactness and create links between the internal and external leaves, which also increases its compressive strength. The correct grout selection should optimize two often competing properties, namely injectability and stability. The flow properties of fresh grouts are as important as their properties in the hardened state, since they govern the ability of the grout to fill a particular type of void. In practice, the variability of voids within masonry requires an ability to fine tune the rheological properties of the grout, in order to optimally fill a given void. So, a methodology was developed with the main purpose being to find not only the best mixing procedures but also the optimal grout composition from a rheological and injectability point of view. The research shows that there are differences in the grout behaviour, especially in rheological properties, when different mixing procedures and/or grout composition (different water/binder or fly ash/binder ratios) are used and that fresh grout properties may be optimized for injection purpose.

Key words
Hydraulic lime grout, rheological properties, mixing procedure, optimization