Ceramics-Silikáty 68, (1) 121 - 131 (2024)

The effectiveness of steel fibres in improving mortar is closely related to their length and dosage To investigate the effect of different lengths and dosages of steel fibres on the performance of mortar, four lengths of steel fibres, namely 6 mm, 13 mm, 25 mm, and 30 mm, were selected, and each length of fibre was single-mixed and multi-mixed following the volumetric rates of 0.5%, 1%, 1.5%, and 2%. The frost resistance of the steel fibre mortar was also analysed by freeze-thaw cycles regarding the compressive strength and flexural strength loss rate. The results showed that the compressive strength of the specimens was significantly improved as the four lengths of fibres were mixed in equal proportions of 1%. The flexural strength was most obviously increased when the four lengths of fibres were mixed in equal proportions of 1.5%, and the compression-flexural ratio was the smallest. At this time, the mortar had the best comprehensive performance. It was also found that the mixing the different lengths of steel fibres at a dosage of 1%∼1.5% in equal proportions resulted in a more uniform distribution of fibres. It improved the mortar better than the single mixing. After the 100 freeze-thaw cycle tests, the loss rate of the steel fibre mortar specimen was significantly lower than the ordinary mortar specimen. Mixing different lengths of steel fibres can improve the mechanical properties and frost resistance of the mortar more effectively.