Study of microfine cement grout penetrability under pressure in deteriorating historic mansonry structures: effect of a colloidal agent

Several masonry structures, built over the past centuries, have to be resto red to ensure their structural integrity and their conservation. Important research and development projects have been initiated by Public Works and G overnment Services Canada to rehabilitate some of these structures, such as the Rideau canal locks, by using a cement-based grouting technique. By fol lowing grouting pressures and flow rates, the stability of the structure is protected and the efficiency to fill openings is assured by using microfin e cement-based grouts with admixtures. However, cement grout penetration ca nnot be observed with precision during the injection. The project described in this paper presents the grouting treatment of a Rideau canal lock sill wall that had to be demolished and reconstructed. The penetration of two di fferent grout mixes was observed by removing the front row of blocks, piece by piece. A second phase of this study was conducted in the laboratory to compare the penetration of different grouts in a reconstructed granular mat erial which simulated the lock's interior walls.