New functionalities of textile-reinforced concrete through titanium dioxide modifications Subsidiary project: fine-grained concrete and cement-bound adhesive

The functional properties of textile-reinforced concrete that has been modified by the addition of nano particles are being researched as part of this composite research project. The use of nano particles of titanium dioxide (TiO₂) is opening up new areas of application, e.g. as bondable facade elements, and additional functionalities such as self-cleaning and the decomposition of pollutants.

The working plan of the Research Institute of the Cement Industry is aimed at systematic investigation of the mix formulation and workability of a nano-based cement-bound adhesive. The adhesive should have good workability and very good adhesive properties to textile-reinforced concrete. The particle size distribution of the adhesive mix formulation is being optimized for this purpose and modified with organic admixtures (dispersants, cellulose ether). The adhesive properties will be determined with the aid of tensile bond and adhesive shear tests using the procedures described in the standards DIN EN 1348, DIN EN 1324 and DIN EN 12003. Fine-grained concrete slabs provided by the project partner ibac (Aachen University of Technology) will be bonded, exposed to different types of storage (dry, hot, water and alternating freeze-thaw storage) and tested.

The effects of TiO₂ modifications of the fine-grained concrete slabs on the adhesion will also be investigated. The fine-grained concrete slabs are being irradiated with a UV lamp in order to activate the TiO₂ nano particles. Super-hydrophilic surfaces (angle of contact between a water droplet and the concrete surface < 10 °) are being obtained, depending on the wave length, and the intensity and duration of the irradiation. How such a surface affects the adhesive properties of cement-bound adhesives is also being investigated with tensile bond and adhesive shear tests.