Ceramics-Silikáty 65, (4) 317 - 325 (2021)

This research investigates the effect of the amount (from 2.5 % to 15 %) of natural zeolite on the alkali silica reaction resistance (ASR), density, ultrasonic pulse velocity and mechanical properties of mortar. Research revealed that physical and mechanical characteristics of mortar mix improve with higher amount of natural zeolite, however, the appropriate zeolite amount must be selected because overdosing leads to deterioration of mortar mix properties. The impact of natural zeolite and the amount used on the expansion of mortar specimens was tested using Rilem AAR-2 method. Altered composition mortar specimens were tested using SEM and X-ray structure analysis, their mineral composition was determined. Dependence between natural zeolite amount in mortar mix, mineral composition of hardened mortar and expansion was determined. Test results revealed that alteration of mortar composition by natural zeolite not only improves physical and mechanical properties of the mix but also increases alkali silica reaction resistance (ASR) of mortar. The tests revealed that alteration of mortar composition with 15 % of natural zeolite (replacing cement mortar mix) increases durability and resistance to alkaline silica reaction.