The most important characteristic of building materials and products based on cement is the strength after 28 days of hardening under normal conditions. Currently, however more and more attention is paid to development of fast-curing systems, resulting in need for analyzing the kinetics of hardening cement systems in early stages. Article presents the results of experimental researches of determination the relationship between growth strength of cement-sand mixture and amount of heat power released during hydration pure cement. And also the effectiveness of accelerating admixture for cement systems is established by comparing the heat release curve obtained for modified composition and similar curve obtained for control composition. In the course of present work it was revealed that for two cement systems differing only in presence of monofunctional accelerator it is possible to compare indirectly the growth dynamics of strength through integral heat flow curve during hydration binder and using the isothermal calorimetry. This demonstrates the possibility to simplify selection the optimal accelerating admixture in development of concrete mix and other building mixes by using methods presented in the article.