PSI - Issue 42

Stanislav Seitl et al. / Procedia Structural Integrity 42 (2022) 1512–1519 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Tab. 3 Fatigue test results of concrete with various w / c (0.5, 0.4, 0.3) and different D max = 8 and 16 mm.

ǁ / Đ , max

  a (1) [MPa]

  a (2×10

6 )

Maximum stress level [%]

[MPa]

0.5, D max = 8mm

2.83 3.13 3.60 3.45

1.42 1.81 2.25 2.03

50 58 63 59

0.4, D max = 8 mm 0.3, D max = 8 mm 0.3, D max = 16 mm

Fig. 5. Fatigue results of concrete with water to cement ratio 0.3 and various D max = 8 mm, 16 mm and its Kohout- Věchet fit.

Based on the results above, it is clearly shown that the w / c can significantly affect the fracture mechanical and fatigue properties. The experimentally obtained data is recommended for practical applications (or input data) for advanced modelling Alliche (2004), Elias & Le (2012), Baktheer & Chudoba (2019), etc. 4. Conclusion A fatigue study was conducted on prism concrete specimens with various w / c ad D max loaded by tree – point bending with notch. From this experimental research work, the following conclusions can be drawn • This study found that the w / c ratio has a significant effect on the fracture mechanical and fatigue properties, especially on the endurance fatigue limit. • The fatigue resistance increases with decrease of w / c from 50 % for w / c = 0.5 up to 60 % for w / c = 0.3. • This study found that the maximum size of aggregates has not a significant effect on the fatigue properties, especially on the fatigue limit 2×10 6 cycles; this means that the weak point of the concrete is the concrete pasta/composition.