Parameters of Mortars Made of Aluminium and Portland Cement

Alumina cement is included in special cements, which are used primarily for the production of refractory materials. It is significantly different in chemical terms from the Portland cement commonly used in construction. The consequence of this are the different properties of these two hydraulic binders. Portland cement consists mainly of CaO and SiO₂. In turn, the main constituents of aluminium cement are Al₂O₃ and CaO, which form calcium aluminates. However, the main phase constituent of aluminium cement is CA calcium monohydrate. It consists of about 36 ÷ 42% Al₂O₃ containing also a significant amount of gelenite (C₂AS). Strength of Ca₂ after three days of hydration is comparable to the strength of pure hydrated CA. It is also worth mentioning such phases as C₂S and C₄AF. They often occur in Portland cement and in clay cement. The article discusses the results of laboratory tests on the impact of replacing Portland cement with Portland cement on the physical and mechanical properties of mortar. The rheological characteristics of mortars, i.e. the consistency and parameters of hardened mortars, among others compressive strength, capillary rise and absorbability. Replacing aluminium cement with Portland cement in an amount of 10% causes an increase in compressive strength. The increase in compressive strength depends on the amount of Portland cement applied to the mortar. Parameters such as absorbability and capillary rising are improving. Compressive strength was tested after 1, 7, 28 days on samples with dimensions 4 × 4 × 16 cm. Absorption and capillary rising were tested 28 days after being moulded. (paper)