The Influence of Steel, Glass and Basalt Fibres on Selected Parameters of Construction Mortars

Dispersed reinforcement in cement mortars plays a key role in increasing their durability and strength. The fibres act as binding elements in the structure, preventing the development of microcracks that can weaken the material. Fibres increase mechanical strength, elasticity and resistance to tension and compression, which translates into better physical and mechanical parameters of the material compared to mortars without fibres. The aim of this study was to determine the physical and mechanical parameters of mortars with the addition of currently produced steel, glass and basalt fibres. The influence of the selected fibre type on the compressive and flexural strength, water absorption and capillary rise of mortars was investigated. The rheological properties of the mortars, i.e., consistency and volume density, were also investigated. Compressive and flexural strength was tested after 7, 28 and 56 days, while capillary rise and water absorption were tested after 28 days of curing. The frost resistance of the mortars was also determined. For the mortars tested, correlations were established between compressive strength and flexural strength, as well as between water absorption and capillary pull-up. A full statistical analysis was performed for two parameters, i.e., compressive strength and capillary pull-up. The introduction of basalt fibres into the mortars resulted in an increase in compressive strength by approximately 5% and in flexural strength by 48% after 56 days of curing. A lower mass increase of approximately 30% was also observed in relation to the reference series in the water absorption and capillary pull-up test for the series of mortars with glass fibres.