For use in white concrete, we recommend the untreated TiO2 grades TINOX A-2380 (anatase) and TINOX SUR-100 (rutile). Both grades are pure TiO2 pigments without posttreatment and characterized by a pH-value close to the neutral point, low salt load, and excellent dispersibility in aqueous highly concentrated slurries.
Where road markings made of white concrete are used, pigmentation with titanium dioxide pigments is one of the basic prerequisites for generating optical guidance effects as road markings.
TiO2 pigment concentrations in the amount of (3-5) % relative to white cement lead to a significant increase of end-product brightness, which is caused by the excellent tinting strength of the TiO2 pigment. The brightness achieved in the concrete end-product is maintained when TiO2 pigment is used in white concrete, even under conditions of wetness and fog (figure 1). Other substances added to white concrete do not meet these requirements because their refractive indices are nearly similar to those of water, which leads to a decrease in brightness under wet conditions.
There are also other important requirements that TiO2-pigments have to meet, when they are applicated in white concrete.
- TiO2 pigments used should be as free as possible of soluble salts and have neutral pH in aqueous precursors.
- All components of the TiO2 pigment must be water-insoluble and the pigment color tone mustn´t be influenced by cement.
- TiO2 pigments used must not impair the mechanical properties of the concrete(figure 2).
Author: Daniel Moog, Technical Support, Tinox Chemie GmbH.