Lime-based injection grouts with reduced water content: An assessment of the effects of the water-reducing agents ovalbumin and ethanol on the mineralogical evolution and properties of grouts

Non-structural lime-based injection grouts with reduced water content were designed for the stabilisation of delaminated plasters in water-sensitive contexts. Two water reducing components were considered: (i) ethanol, as a partial substitute for water, being a less effective solvent for ionic substances, (ii) ovalbumin, a protein found in egg white (it is a water-reducer and air-entrainer). The influence of ethanol and ovalbumin on grouts was assessed in terms of its effect on chemical reactions and formation of phases, the internal structure of the set binders and porosity, through a combination of X-ray powder diffraction coupled with quantitative phase analysis by means of the Rietveld method, scanning electron microscopy with EDS microanalysis and X-ray micro-computed tomography. Water vapour permeability, capillary water absorption and mechanical strength of the materials were tested with standard methods. The results show that both ethanol and ovalbumin affect formation of phases, grout internal structure and porosity, and thus other related physical-mechanical properties. The grouts designed have properties that allow their potential for in situ implementation, with the advantage of water reduction.