<p>The objective of the research is to examine the performance and durability of high CO₂-exposed mortar cubes through the analysis of properties such as compressive strength, carbonation depth, water absorption, and resistance to chemical attack. The study used two different types of mortar: traditional mortar and alkali-coated mortar (cast in alkali-coated molds). XRD analysis was used to examine the calcium and sodium carbonate by-products of the CO₂ reaction. The results revealed that mortars exposed to high CO₂ had significantly higher compressive strength than the low CO₂ ones. Traditional mortar compressive strength increased from 10&#xa0;MPa (low CO₂) to 21&#xa0;MPa (high CO₂). The compressive strength of the high CO₂ alkali-coated mortars slightly increased, which is about 7.5%. The presence of Na₂CO₃ was detected in both high CO₂ and low CO₂ alkali-activated mortars, indicating an interaction between the ambient CO₂ and the applied NaOH. Subsequent investigations may concentrate on optimizing CO₂ exposure parameters, investigating long-term durability concerns, and analysing the influence of the alkali pre-treatment on CO₂ uptake and other mechanical properties.</p>