How Much Should I Prepare the Repair? - Preparing Cementitious Repair Mortars for High-Performance Topcoats

Abstract Cementitious repair mortars are commonly used to repair and rehabilitate deteriorated wastewater concrete infrastructure prior to the application of high-performance lining systems. Often, a broom finish is deemed by specifiers as being an acceptable profile for the mortar before the application of a thick film lining system. Others, however, specify guidelines for abrasive blasting of the repair material, which aims to remove any laitance that may have formed on its surface and to create an anchor profile for the subsequent high-performance topcoat. This additional surface preparation has long been perceived as helping the lining material to achieve a more tenacious mechanical bond to the repair mortar. In this paper, the authors assess different degrees of surface preparation of various cementitious repair mortars. Generic technologies, such as Portland cement mortars, microsilica mortars, calcium sulfoaluminate mortars, and others will be discussed in this study. Ultimately, the discussion will focus on the pros and cons of each technology and how different degrees of surface preparation of each of these types of repair mortars affect the corresponding adhesion values of high-performance topcoats.