# The Influence of Steel, Glass and Basalt Fibres on Selected Parameters of Construction Mortars
## 2 Materials and Methods  
The research programme involved four mortar series: one without fibres and three with steel, glass and basalt fibres. Portland CEM I 42.5 R cement was used following PN-EN 197-1:2011 [39]. Quartz sand (0-2 mm) was used as aggregate according to PN-EN 12620+A1:2010 [40], along with tap water [41] and a single type of fibre per series. All tests were conducted in laboratories at the Kielce University of Technology. The mortar mix followed a standardised water-to-cement ratio (w/c = 0.5) and was prepared according to EN 196-1:2016-07 [42]: cement and water were mixed for 30 s and then sand was added during the next 30 s, followed by another 30 s of mixing. Then, fibres were introduced, and the mixture rested for 90 s before a final 60 s of mixing. Samples (4 cm \(\times\) 4 cm \(\times\) 16 cm) were then cast. The specimen codes were as follows: \"SW\" for plain mortar, \"SZ\" for glass fibre, \"SB\" for basalt fibre, and \"ST\" for steel fibre. The steel fibres (12.5 mm length, 1 mm diameter, straight shape) met EN 14889-1:2007 [43] requirements. Their elastic modulus was \(\geq\)180 GPa and their tensile strength was 1020 N/mm\({}^{2}\). The recommended dosage was 20-40 kg/m\({}^{3}\), with 25 kg/m\({}^{3}\) used in this study (Figure 1a, Table 1). The glass fibres (12 mm length, 14 \(\upmu\)m diameter, \(<\)0.6% moisture, 1% binder, green colour) followed ISO 9001:2016 [44], ISO 3344:1977 [45], and ISO 1887:1980 [46]. The manufacturer recommended 5-10 kg/m\({}^{3}\), with 5 kg/m\({}^{3}\) applied here (Figure 1b, Table 1). The basalt fibres, known for their high chemical resistance, had a density of 2.65 g/cm\({}^{3}\), a tensile strength of 3.0 GPa, and an elastic modulus of 90 GPa. They measured 10 mm in \begin{table}
\begin{tabular}{c c} \hline
**Fibre Type** & **Parameters** \\ \hline Steel & \\ \hline  & Tensile strength [MPa] & 1200–1700 \\ \hline  & Elasticity module [GPa] & 210–220 \\ \hline  & Fibre diameter [\(\upmu\)m] & 300–1000 \\ \hline  & Fibre length [mm] & 4–60 \\ \hline  & Density [g/cm\({}^{3}\)] & 7.85 \\ \hline Glass & \\ \hline  & Tensile strength [MPa] & 2000–3400 \\ \hline  & Elasticity module [GPa] & 70–85 \\ \hline  & Fibre diameter [\(\upmu\)m] & 3–13 \\ \hline  & Fibre length [mm] & 3–25 \\ \hline  & Density [g/cm\({}^{3}\)] & 2.56 \\ \hline Basalt & \\ \hline  & Tensile strength [MPa] & 400–700 \\ \hline  & Elasticity module [GPa] & 80–110 \\ \hline  & Fibre diameter [\(\upmu\)m] & 5–20 \\ \hline  & Fibre length [mm] & 3–25 \\ \hline  & Density [g/cm\({}^{3}\)] & 2.70 \\ \hline \end{tabular}
\end{table} 
Table 1: Parameters of steel, glass and basalt fibres. Figure 1: Fibres added to mortar: (**a**) steel, (**b**) glass (**c**) and basalt. length and 0.01 mm in diameter. The recommended dosage was 1 kg per 100 kg of cement, which was used in this study (Figure 1c, Table 1). The different proportions of fibres added to the mortars result from our own experience in laboratory testing and the recommendations of the manufacturers of the fibres tested. This is due to the fact that each type of fibre has different parameters. Basic information on the properties of CEM I 42.5 R cement is provided in Table 2.  
Analysis of the granulometric study of the cement (Figure 2) showed that the particle size of 50% of the cement is smaller than 9.14 \(\upmu\)m. However, the highest concentration of particles is found in the fraction range from 1 \(\upmu\)  
The laboratory tests examined the effect of curing time and fibre type on selected parameters: compressive and flexural strength, water absorption and capillary rise. Additionally, fresh mortar properties such as consistency and bulk density were analysed. The mixed mortar was transferred to moulds, enabling the preparation of samples measuring 4 cm \(\times\) 4 cm \(\times\) 16 cm. The moulded samples were placed above water for 24 h and covered with foil to prevent evaporation of the mixing water.