# The Influence of Steel, Glass and Basalt Fibres on Selected Parameters of Construction Mortars
###### Abstract  
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. c 202515  
from the engineering community. The main objections were related to the rheology and durability of structures containing fibre materials. Today, after more than thirty years of experience in Poland, scientific research and practical applications, it is clear that these materials are reliable [1; 2; 3]. By using different types of fibres, we can influence the parameters and properties of materials [4; 5]. Here, we discuss cracks that appear in the rather brittle cement matrix. These cracks can damage the element, affecting its durability and, in many cases, the safety of the entire structure [6; 7]. Given the brittleness of the cement matrix, it is impossible to avoid cracks. It is therefore important to avoid cracks that can penetrate the main reinforcement [2; 8]. The most effective way to deal with the formation of dangerous cracks is to use dispersed reinforcement in the form of fibres. The popularisation of these solutions has led to the inclusion of fibres in the PN-EN 206:2014-04 standard for concrete [9]. In this standard, we can find only two types of fibres in terms of material. These are steel and polymer fibres. There are no standard guidelines for other fibres [10; 11]. Among the applicable guidelines of the American Society for Testing and Materials, ASTM C116/C1116M-10a [12] standards have been developed for requirements for different fibres, depending on the material from which they are made. The classification includes four types. Type I is steel fibre-reinforced concrete, type II is glass fibre-reinforced concrete. Type III describes concrete reinforced with synthetic fibres, while type IV is concrete reinforced only with natural fibres [12]. The properties of the composite depend mainly on the orientation of the fibres, their arrangement in the element, and the repeatability of the quality of the fibres used. Despite great care and quality control during fibre production, minor problems may arise at the microscopic level of the fibre structure, which may affect the overall properties of the fibre composite. Excessive fibre clusters at a given point, as well as their absence in other places, can lead to significant changes in the properties of a given material. Fibres are characterised by high stiffness and strength, significantly exceeding the value of a given material in the form of mass.