<p>Calcium ate-aluminate-cement (CAC) is a specialised building material that is mainly used in refractory concretes and some structural applications. It is characterised by fast hardening, high early strength, and resistance to chemical aggression. Reference samples (CON) and samples with the addition of calcium aluminate cement (ALU) in amounts ranging from 5 to 20% by weight were prepared. for the experimental studies. The concrete mix was tested for consistency using the slump cone method, apparent density by measuring the mass and volume, and mix viscosity using the t₅₀₀t₅₀₀ method. For hardened concrete, the compressive strength, frost resistance, water absorption, and depth of water penetration were tested. To assess the effect of calcium aluminate cement on microstructural changes, a microstructure analysis was carried out. Studies indicate that calcium aluminate cement works well in low-temperature andenvironments and can be effectively used as an additive to Portland cement composites in small amounts. A CAC content of 5% has a positive effect on the mechanical properties and durability of concrete, making it particularly suitable for applications that require rapid strength and frost resistance. However, higher CAC concentrations require caution because of the potential reduction in the strength and durability of concrete over a longer service life.</p>