Method for Healing Corrosion-Caused Degradation of Concrete and Causes of Efflorescence

Abstract

The emergence of efflorescence may be traced back to a complex web of interconnected processes that include many different paths. Efflorescence, in its most fundamental form, is the consequence of bringing water containing dissolved salts to the surface of masonry, letting the water to evaporate, and then allowing the salts to remain on the surface of the brickwork after the water has evaporated. Salt solutions have the potential to migrate either over the surfaces of masonry units, through the spaces between mortar and brick units, or via the pores of the mortar or brick units. In addition to this, salt solutions have the potential to seep through the pores of the mortar or the brick units.Alkaline solutions (often alkali metal silicates or hydroxides) combine with solid alumina-silicate precursors to create these binders (Davidovits, 1991, 2008). The transformation of a solid alumina-silicate precursor into a synthetic amorphous or nano-crystalline binder has been modelled in a simplified fashion by Provis et al. (2005). Their scenario begins with the oligomerization of silicate and aluminate monomers following the dissolution of a solid alumina-silicate source in an alkali-activator. Polymerization and gelation of the generated alumina-silicate oligomers can result in either an amorphous alumina-silicate phase or a Nano-crystalline zeolite phase, depending on the processing circumstances.