Ordinary Portland cement (PC), calcium sulphoaluminate -belite (SAB) cement and a 85 wt. % SAB cement/15 wt.% PC blend were used formortar manufacture (cement to sand weight ratio 1 : 3, w/c ratio 0.5) of 40x40x160mm specimens kept in wet air cure (20_C, 100 % R.H. for 90 days), and used forthe tests. The results reveal the influence of cement type on mortar pro-perties.The mortars, made from tested SAB cement have the worst mechanical properties.The replacement of 15 wt. % of SAB cement by PC contributes to the increase indynamic modulus of elasticity (DME), flexural strength of the mortar by 15 % andcompressive strength almost by 40 % compared to the SAB cement mortar. Suchmortar behaves mechanically similar to PC mortar. Differences in mechanicalproperties of mortars are caused by differences in chemical composition ofcements (in SAB/PC mortar content of CaO is increased by 6.4 %, contents of Al2O3and Fe2O3 are decreased by 8.2 % and 7.0 %, respectivelycompared to SAB cement mortar, SO3 content is 2.6 higher than that inthe PC mortar), and mineralogical composition and hydration kinetics of cements.Differences in mineralogical composition, mainly ettringite formation, andconsequent-ly hydration kinetics are the substantial reason of higher demands onbatch water, rapid initial and final set of SAB cement and lower DME andstrength of SAB cement mortar relative to PC and PC mortar, respectively. The 85wt. % SAB cement/15 wt. % PC blend gains on hydration activity, DME and strengthgrowth by the C3S activator from PC supporting less-active SAB cementhydration. Utility properties of SAB/PC mortar are more similar to PC mortarthan SAB cement mortar.
