Influence of nano-lime and nano-silica consolidants in the drying kinetics of three porous building materials

Abstract

In this report we describe an experimental study carried out at LNEC within the research project DRYMASS (ref. PTDC/ECM/100553/2008). The study was aimed at evaluating the possibility of increasing the drying rate of porous building materials by means of nano-treatments. It was justified by previous results of other authors that observed an apparently unexplainable increase in the evaporation rate of natural stone after application of nano-calcium hydroxide solutions as consolidating agents. Two commercial treatments, consisting on alcoholic or aqueous suspensions of nano-lime or nanosilica, respectively, were tested on three porous building materials. The treatments are generally used for consolidation. The materials were a lime mortar and two natural stones (Ançã limestone and Bentheimer sandstone). It was concluded that neither of the nano-treatments hinders drying. However, they were also not able to increase the drying kinetics of any of the three substrates.