Issue 72

H. S. Vishwanatha et alii, Fracture and Structural Integrity, 72 (2025) 80-101; DOI: 10.3221/IGF-ESIS.72.07

obtained during three-point bending (TPB) tests. By equating the area under the softening curve to the fracture energy of concrete, w 0 can be determined.   f n t G w f 0 The parameter α n is determined differently across various models. In Hillerborg’s model [25], α n is assigned a value of 3.5. According to the CEB-FIP model [18], α n depends on the maximum aggregate size, taking a value of 7 for a maximum aggregate size of 16 mm and 5 for a size of 32 mm. However, an alternative version of the CEB-FIP model [19] simplifies the calculation by consistently setting α n to 5, regardless of the maximum aggregate size. Based on the results of the present study, the α n values presented in Tab. 5.

Figure 18: Relationship between the w o and G f / f t .

Fig.18 shows the relationship between the w 0 and G f /f t . It can be seen from the Fig.18 that, the w 0 increases with the increasement of G f /f t , which can be well approximated by a power function. It can be written as

0.983

       f t G f 3.646

w

0

Figure 19: COD profiles of B-SB75.

97