Issue 54

J. Akbari et alii, Frattura ed Integrità Strutturale, 54 (2020) 116-127; DOI: 10.3221/IGF-ESIS.54.08

Code

Description

CN

Normal concrete ( no fibers)

CSF0.3

Concrete + 0.3% steel fiber

CSF0.6

Concrete + 0.6% steel fiber

CSF0.9

Concrete + 0.9% steel fiber

CGF0.3

Concrete + 0.3% glass fiber

CGF0.6

Concrete + 0.6% glass fiber

CGF0.9 Concrete +0.3% glass fiber Table 2: Labeling of the prepared specimens in this research.

W/c 0.35 0.45 0.35 0.45 0.35 0.45 0.35 0.45 0.35 0.45 0.35 0.45 0.35 0.45

CN 140

CSF0.3 CSF0.6 CSF0.9 CGF0.3 CGF0.6

CGF0.9

Water (kg)

140

140

140

140

140

140

157.5

157.5

157.5

157.5

157.5

157.5

157.5

Cement (kg)

400 350 980 975 362 360 561 559

400 350 980 975 362 360 561 559 23.5 23.5 0.80 0.53

400 350 980 975 362 360 561 559 23.5 47.1 1.40 1.05

400 350 980 975 362 360 561 559 23.5 70.6 2.00 1.05

400 350 980 975 362 360 561 559 23.5

400 350 980 975 362 360 561 559 23.5 16.8 1.60 0.88

400 350 980 975 362 360 561 559 23.5 25.2 2.20 1.23

Sand (kg)

Fine Gravel

Coarse Gravel

Fibers

- -

8.4

Superplastizer

0.40 0.35

1.20 0.70

Table 3: Concrete mixtures components (kg/m 3 ) for W/C ratios equal to 0.35 and 0.45.

Compressive strength test The compressive strengths of the specimens were determined at the ages of 7 and 28 days, according to the mentioned standard. For this purpose, at each age, three cubic 100 × 100× 100 mm samples were used to report their mean compressive strength values. The specimens were cured in a water pond at a temperature of about 0 23 C until the age of testing. The ADR 2000 hydraulic press machine with a capacity of 2000 kN with loading speed equal to 3 kN per second was used under the ASTMC39 standard [[28]] to determine the compressive strength. Tensile strength test According to the ASTM-C496 standard [[29]], this experiment was performed at 28 days for cylindrical specimens with a diameter of 150 mm and a height of 300 mm. It should be noted that the ADR hydraulic press machine with a capacity of 2000 kN and loading speed equal to 0.94 kN per second was used for this test (Fig. 2). The splitting tensile strength is calculated from Eq.(1).

119