PSI - Issue 28

Zuzana Marcalikova et al. / Procedia Structural Integrity 28 (2020) 950–956 Author name / Structural Integrity Procedia 00 (2019) 000–000

953

4

tensile strength were tested on 6 specimens in each series and bending tensile strength was tested on 3 specimens in each series. A scheme of all tests performed is shown in Fig. 3.

Table 2. Basic mechanical properties plain concrete and fiber reinforced concrete.

Compressive strength - cube [MPa]

Splitting tensile strength [MPa]

Bending tensile strength [MPa]

Standard deviation [MPa]

Standard deviation [MPa]

Standard deviation [MPa]

Standard deviation [kg/m 3 ]

Density [kg/m 3 ]

Dosage [kg/m 3 ]

Type concrete

Plain concrete

0

2205 2248 2273 2294 2267 2289 2305

49.13 19.26 25.59 23.39 34.46 20.01 27.30

55.87 57.10 64.01 59.32 56.59 60.39 57.55

1.02 3.53 2.73 2.44 2.61 2.31 3.06

2.99 4.18 5.01 5.88 5.18 7.35 7.63

0.37 0.27 0.55 0.35 0.49 0.30 0.35

3.14 4.58 4.78 5.45 5.96 9.65

0.23 0.38 0.16 0.29 0.71 1.54 1.41

40 75

FRC - MasterFiber 482

110

40 75

FRC - Dramix® 5D 65/60 BG

110

12.11

Fig. 3. Experimental program - test scheme.

One of the important monitored properties of fiber reinforced concrete was the splitting tensile strength. The functional dependence of the splitting tensile strength on the amount of fibers in the concrete is the chart in the Fig. 4. There is a relatively high increase in splitting tensile strength compared to plain concrete. For fiber reinforced concrete with MasterFiber 482 fibers with dosage 40 kg/m 3 tensile strength increased by 40 %. In the case of fiber reinforced concrete with Dramix® 5D 65/60 BG fibers, dosage 40 kg/m 3 , even up to 73 %. Based on the functional dependence in Fig. 4, a good agreement of the splitting tensile strength increase model with increasing dosing can also be observed, which can be determined on the basis of the value of R 2 . In both cases of fiber reinforced concrete, the value of R 2 is close to 1.0. Another decisive property of fiber reinforced concrete is the bending tensile strength. The functional dependence of the bending tensile strength on the amount of fibers is shown in Fig. 5. In the case of fiber reinforced concrete with MasterFiber 482 fibers with a dosage of 40 kg/m 3 , an average value of tensile strength in bending of 4.58 MPa was achieved. In the case of fiber reinforced concrete with Dramix® 5D 65/60 BG fibers with a dosage of 40 kg/m 3 , the average value of bending tensile strength was 5.96 MPa. Increase of bending tensile strength compared to plain concrete was 46 % for fiber reinforced concrete with MasterFiber 482 fibers, resp. 89 % for fibers reinforced concrete with Dramix® 5D 65/60 BG fibers. In this case, a good agreement of the model of the dependence of the bending tensile strength on the amount of fibers was also proved. The R 2 value was determined for fiber reinforced concrete with MasterFibre 482 fibers at 88.8 %, resp. for fiber reinforced concrete with Dramix® 5D 65/60 BG fibers to 99.3 %.