Issue 71

V. Bilek et alii, Fracture and Structural Integrity, 71 (2025) 263-272; DOI: 10.3221/IGF-ESIS.71.19

w/b = 0.20

w/c = 0.30

w/c = 0.40

w/c = 0.50

foil

water

foil

water

foil

water

foil

water

28 days 91 days 365 days 720 days 28 days 91 days 365 days 720 days 28 days 91 days 365 days 720 days

13.3 ± 0.5 17.8 ± 0.4 9.3 ± 0.3

9.1 ± 0.3

8.2 ± 0.5

7.3 ± 0.4 9.5 ± 0.5 9.2 ± 0.5 9.6 ± 0.5

7.1 ± 0.2 7.3 ± 0.3 6.6 ± 0.4 7.4 ± 0.6

7.3 ± 0.1

Bending strength [MPa] Compres. Strength [MPa] Modulus of rupture [MPa]

10.7 ± 0.2 16.2 ± 0.7 9.6 ± 0.5 9.15 ± 0.5 9.6 ± 0.3 12.8 ± 0.1 17.5 ± 1.1 11.0 ± 1.3 10.6 ± 0.4 9.4 ± 0.3 13.6 ± 0.7 16.7 ± 0.8 10.2 ± 0.5 10.2 ± 0.7 8.7 ± 0.6

-

7.9 ± 0.6 8.7± 0.4

136.6±3.1 129.2±3.2 78.6 ± 3.5 73.3 ± 2.0 69.9 ± 3.6 64.1 ± 1.5 45.0 ± 1.0 49.0 ± 3.9 135.9±3.6 135.4±4.1 83.2 ± 3.4 86.4 ± 2.9 77.8 ± 1.5 71.0 ± 3.9 51.0 ± 1.5 62.1 ± 3.9 139.0±3.0 136.4±3.3 95.3 ± 2.6 94.0 ± 1.8 81.7 ± 3.7 80.3 ± 3.4 49.8 ± 1.6 63.9 ± 2.1 140.4±2.1 145.6±2.6 95.7 ± 3.0 89.9 ± 2.9 82.9 ± 3.2 80.5 ± 3.1 49.8 ± 3.5 66.7 ± 1.2

8.7 ± 0.5 9.7 ± 0.4 8.5 ± 0.2 9.2 ±0.4

9.1 ± 0.3

7.0 ± 0.7 6.7 ± 0.2 9.5 ± 0.2

6.7 ± 0.4

6.4 ± 0.7 5.9 ± 0.3 7.9 ± 0.2 8.2 ± 0.6

5.9 ± 0.5

5.3 ± 0.7 5.3 ± 0.1 6.3 ± 0.3

5.2 ± 0.2

-

-

-

-

9.6 ± 0.3

7.6 ± 0.3 7.8 ± 0.4

6.4 ± 0.2

5.5 ± 0.2

10.3 ± 0.5 8.9 ± 0.4 7.1 ± 0.3 6.55 ± 0.5 5.95 ± 0.3 Table 2: Values of mechanical properties. Arithmetic mean and standard deviation from three measured values, respectively from 6 values in the case of compressive strength.

Figure 3: Measured compressive strength of concretes with different w/b cured in foil or in water at various ages a) 28 days. b) 91 days. c) 365 days. and d) 720 days.

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