In the ultra short laser pulse regime, the damage process is driven by the interaction of the laser pulse with the electronic structure of the material. The way of excitations in dielectric materials is dominated by multi photon and avalanche ionization processes. Often, the complete theoretical description is limited by the lack of knowledge of the precise material properties. Usually, LIDT measurement data are only available for pure materials (e.g. TiO2, Ta2O5 or SiO2). The development of composite materials opens the way to vary material properties, continuously. Additionally, all material changes are based on the same chemical elements in different compositions. The paper compares measurement results of the University of New Mexico and Vilnius University performed on the same set of TixSi1-xO2-mixtures to calculations based on Keldysh theory. When applying simple approximations for the physical properties of the mixture, the theoretical description agrees well with the measurement results.