Anisotropy of strength properties of aluminate cement after exposure to single-axis loading at early stage of hardening

The article considers the impact of short-term compression at an early age on the flexural strength of aluminate cement. Taking into account the results of the previous research, the authors took the samples with the identical planes instead of prisms. The change in splitting tensile strength of pre-stressed samples at different planes has been analyzed. The studies have shown cement hardening in a plane perpendicular to the direction of short-time compression. It can be explained by the compaction of cement stone, decrease in porosity and formation of additional bonds through the chemical-plastic hardening, as noted by F. J. Ulm and O. Coussy. The research revealed that, after the removal of load, the difference between the strength of pre-stressed and control samples tends to reduce. The X-ray phase analysis demonstrates the difference in the hydration process in the first 24 hours after loading and change in the recrystallization of hexagonal hydroalumates into cubic crystals.