The article presents the results of a study of the stability of mortars for precast piles at different degrees of strength of the set. The research was carried out in the laboratory of engineering geocryology of the Melnikov Permafrost Institute and the laboratory of building materials of the North-Eastern Federal University. A discussion was held of the stepwise strength of mortars with their grade strength starting from the first day to 28 days. The stage of studying the hardness of solutions was carried out using a device for single-plane cutting and bending of a standard beam. Compressive strength was studied on a standard press, on which the wire was tested in cubic samples. Comparison of shear strength data obtained using a single-plane cut tool and data obtained from a standard ball testing by bending, which provides the greatest accuracy of the first assistant. It has been established that the shear resistance of soil solutions when the surface freezes under the influence of the foundation will largely be stable not only from temperature, but also from the composition of the applied solution. The research results can be used in predicting minor abilities caused by allowing them to thaw.