Physico-Mechanical Features of Portland Cement Mortars Replaced Partially with Aluminium Cement

Abstract

The purpose of the research was to recognize the effect of the addition of aluminium cement on the properties of cement mortar made of Portland cement CEM I 42.5R. Alumina cement is a hydraulic binder. It is a finely ground organic material that when mixed with water binds as a result of reactions and hydration processes. After hydration, stable hydrate phases form and, as a consequence, the material strength parameter is obtained. The main constituent is calcium aluminate (CaO⋅Al2O3), in smaller amounts there are: calcium aluminate, dicalcium silicate and calcium aluminium silicate or gelenite. Hydraulic hardening of aluminium cement occurs mainly through calcium hydration but other chemicals may also take part in the hardening process. The specific chemical composition of aluminium cement and the fact that calcium hydroxide is not released during hydration allows the leaven to resist many aggressive factors. Therefore, in the literature, we can meet guidelines so that the w / c ratio is not greater than 0.40 for applications to structural elements. The article discusses the results of laboratory tests on the impact of replacing Portland cement with aluminium cement in the amount of 10%, 20%, 50%, 100% on the physical and mechanical properties of mortars. The rheological properties of mortars, i.e. consistency, setting time and parameters of hardened mortars were examined, among others compressive and bending strength, capillary rise and absorbability. Compressive strength and bending strength were tested after 1, 7 and 28 days on samples with dimensions 4 × 4 × 16 cm. Absorption and capillary rupture were tested 28 days after being formed on standard bar beams 4×4×16cm. The mortar was made with a constant coefficient w/c = 0.38.