Carbon Admixtures Influence on the Electrical Properties of Slag Mortars Focusing on Alternating Conductivity and Permittivity

New materials based on alkali-activated slag mortars may be an important contribution of applied research, which strives to offer the use of waste materials as a full replacement for the currently used binders and explores the impact of forms of carbon incorporation on the physical and mechanical properties. The influence of graphite powder addition on the electrical properties of alkali-activated slag mortars was investigated. 1–10 wt. % of graphite powder (with 1% step) was incorporated into the mortar and the electric resistance spectra, permittivity and loss factor of the prepared prismatic samples were measured. The unique Vector analyzer R&S ZNC with a coaxial probe DAK-12 from Speag was used to determine permittivity and loss factor, electrical resistance was measured using two channel oscilloscope. Higher content of graphite powder increases the electrical conductivity, which makes the tested materials more sensitive and measurable via electromagnetic methods. The most striking change in the relative conductivity was observed at excitation frequency of the external electric field of 10 kHz. At high frequencies electrical excitation field 10 MHz to 3 GHz were determined by vector analyzer value of the real part of permittivity, which fell from the 20 to the 4. Dissipation Factor shows in his semi arc spectrum a peak at 1.2 GHz. These measurements are among the building materials still little used and open new possibilities of diagnostics.