**1. Introduction**

The objective of this study was to investigate the effect of two types of basalt fibers in two different types of concrete mixes. The types of concrete that were used were of standard C30/37: XC1, containing aggregate size limits of maximum 19 and 4 mm. The basalt fibers used are Reforcetech minibar, which is a stiff basalt fiber of diameter 0.72 mm and length 50 mm, and Basaltex BCS17-25.4-KV1, which is 30 mm in length with a flat cross-section of 0.017 × 4 mm. The cement met the specifications of NS-EN 197-1:2011 for Portland cement CEM I 52.5 N.
