Microdrilling resistance measurements system and mortar penetrometer: two methods for evaluating in situ mortar resistance

In situ evaluation of mortars' resistance and consolidant treatments' performance in ancient buildings is an essential argument in their conservation. Moreover, the mechanical properties of an ancient mortar are directly connected with the state of preservation of the building or the structure in which it is included, and it is not a parameter easy to be determined, especially for the masonry joints. Mechanical methods often request sampling and laboratory tests, while only few micro destructive techniques are known as penetrometric tests. They can be either static (with action of a pressure drills) or dynamic (with action of a percussion drills) and commonly usable in situ. Among them, Microdrilling Resistance Measurement System and Mortar Penetrometer are two important methods for determining the resistance of a mortar. In the present work these two useful techniques are compared, in order to find a correlation between them which help to control and determine the resistance of a mortar, in addition to define the state of preservation or the effectiveness of the application of a consolidant product on a mortar surface.