Durability of Cement Based Mortars Containing Crystalline Additives

The paper focuses on the study of the durability of cement mortars made with secondary crystallization additives. It investigates the influence of the crystalline additives on the degradation process of cement mortars exposed to gaseous CO2 and freezing cycles. The specimens with were tested for compressive and flexural strength at the following ages and after being treated by the following curing techniques: 28 days, 180 days and 25 freezing cycles, 28 days and 180 days in gaseous CO2. In order to explain the obtained results and to gain new information about the microstructure of the cement mortars being studied, the SEM sampling and RDA analysis were performed. The research results confirm an improvement in the resistance of cement based mortars using crystalline additives against cyclic freezing as well as gaseous CO2. An important parameter that influences the effectiveness of the crystalline additive is the curing conditions during the first 28 days of ageing.