Raman microscopy is a powerful tool for in situ non destructive investigations of various micromechanical phenomena in composite materials. In proposed project Raman spectroscopy will be used to assess changes in the stress transfer between a reinforcing poly(ethyleneterephthale) strips and a cement matrix as a function of the time, temperature and environment. The spectroscopic approach will supported by additional experimental techniques and micromechanical modeling. Correlation between the physical and chemical properties of system PET/cement matrix and interphase between strip and matrix during hardening will be find. Based on the spectroscopic and stress-strain data obtained from the model strip/cement matrix samples, a rapid procedure for characterization of composite micromechanic developed and optimized using Raman microspectroscopic method. The method will be applicable not only for analysis of the PET strip/cement matrix, but also for other polymer/cement systems.