A composite cement-asbestos samples were placed in a corundum crucible and heated for 1 hour in an electric furnace. After the heating process the samples were subjected to microstructural investigations using scanning electron microscopy. These tests were carried out using a JEOL JSM-6610LV microscope after covering the samples earlier with a conductive layer of gold. X-ray examinations were also carried out to identify the asbestos form and evaluate the phase changes caused by the thermal treatment. XRD tests were carried out using the powder method on a Philips X'Pert Pro diffractometer. The measurement step was 0.008° and count time -50 s. Phase identification was performed based on data from the ICDD PDF-4 database. In the case of the selected samples, spectroscopic tests in the mid-infrared range - 4000 - 400 cm-1 (MIR) were also carried out. These tests were performed using a Bruker 70V spectrometer. Spectroscopic samples were prepared in the form of KBr pellets. The measurements were made by the transmission technique, and spectra were recorded on the scale of absorbance at 256 scans and 4 cm-1 resolution. The chemical composition of the samples was determined using an Axios Max WD-XRF X-ray fluorescence spectrometer with wavelength dispersion using a 4kW Rh lamp