Dynamics of early skin formation of tiling mortars investigated by microscopy and diffuse reflectance infrared Fourier transformed spectroscopy

A freshly applied mortar layer is exposed to the environment and forms a skin in the following minutes. Skinning changes significantly the surface properties and therefore limits application procedures. In the case of a tile adhesive, the skin that is formed before the tile is embedded can reduce resulting adhesion properties. Reflected light microscopy reveals that surface “lakes” disappear between 5 and 10 min after mortar application and DRIFTS (diffuse reflectance infrared Fourier transformed spectroscopy) indicates that films of organics and carbonates form simultaneously at the surface.