**2. Materials and Methods**

### *2.1. The Study*

The layout of the experiment consisted of the use of two types of basalt fibers manufactured by two different manufacturers, with the dose values for basalt fibers of 12 kg per cubic meter of concrete. The research method was based on "EN 14488-3 Testing sprayed concrete—Part 3: Flexural strengths (first peak, ultimate and residual) of fibre reinforced beam specimens".

The BFs used in this study were of two different kinds, one of stiff minibars and one of a soft fiber type. Table 1 shows the characteristics of each type.


**Table 1.** Technical characteristics of the basalt used in the study.

The Reforcetech bar is a stiff basalt fiber used in this study. Its diameter is 0.72 mm and length 50 mm, and the length factor 70. Basalt strands have been twisted together and mixed with Vinylester resin and, as a result, it has a coarse surface causing better bonding with concrete to prevent extraction. See Figure 1.

**Figure 1.** The Reforcetech bars.

Basaltex is the other type of basalt fiber used in the study. It is soft, composed of microfine strands of bundles that are slightly stiff but soften when treated and broken apart. It is about 30 mm in length with a flat cross-section already joined together in a bundle. See Figure 2.

**Figure 2.** The Basaltex fibers.

Reference is made to ÍST EN 14488-3:2006 and the ACI study (American Concrete Institute), ACI 544.4R-18, which defines the ASTM C1609 M, for the results of the tensile ductility test. The key data and processes for the project were extracted from a four-point bend resistance test. The explanation for why a four-point test was used instead of a three-point test is that it gives a more accurate result when considering the effect of the fiber on the distribution of the load. The bending tensile strength shows a bending strain. In particular, the maximum post-peak load behavior shall be investigated.
