The performance of an injected grout depends on the dimension of the voids to be filled and on several factors inherent in the grout (such as fluidity and stability, which are determined by the combination of other primary factors like the quantity of water, the shape of the grains, and the speed and duration of mixing). The injection column developed at the Laboratory of Bridges and Roads appears to permit an evaluation of the injectibility of a grout with more precision than Marsh's cone. The use of cements with a low percentage of alkaline materials and filters can improve the chemical and mechanical properties of grouts intended for ancient masonry. See also AATA 19-1792.