Issue 67

B. O. Mawlood et alii, Frattura ed Integrità Strutturale, 67 (2024) 80-93; DOI: 10.3221/IGF-ESIS.67.06

   

   

f

b f



 



a b

c

(5)

ln

'

c

The empirical constants a, b, and c can be estimated as − 13.702, − 14.783, and 2.216, respectively, for the fitted equation, with statistical analysis providing reduced chi-square, R-square (COD), and adj. R-square of 0.8599, 0.8983, and 0.8971, respectively. By using Eqn. 4 and substituting the experimental mean strength, can be estimated as 6.750 and 7.954 for normal concrete and concrete including disc waste, respectively. Despite the fact that Eqn. 2’s value for normal concrete is 1 in compliance with ACI code requirements, the factor was normalized by dividing 6.750 to obtain a new value that is 1.2 for concrete with disc content.

Figure 8: Data fit equation in concrete type factor determination.

C ONCLUSIONS

T

he results gathered from 36 pull-out test specimens on cylindrical concrete were used to examine how the behavior of the bond strength between the steel bar and the surrounding concrete was affected by the behavior of disc waste shreds (CDs and DVDs) led to the following conclusions: 1. In general, at a specific disc content of approximately 4%, replacing a portion of the fine aggregate in concrete with waste CD and DVD shreds improves the mechanical properties of the concrete. The improvements in compressive strength, splitting tensile strength, and flexural strength reach 11.4%, 12.5%, and 28.9%, respectively. 2. The average compressive strength is more than the minimum allowable compressive strength specified in the ACI code for structural concrete (i.e., 17 MPa). 3. Concrete that contains discs splits into more fragments than typical concrete. This result indicates that the load was effectively distributed from the steel bar to the surrounding material. 4. For a bar diameter of 10 mm, the bond strength is improved as the embedded length increases for all mix groups; the perfect bond strength is achieved in all specimens at 150 mm embedded length, except for specimen D4-11, which had 4% of the disc contained at 100 mm embedded length. 5. However, for a bar diameter of 12 mm, the bond strength decreases as the embedded length increases for specimens of the M1 (specimens D0-1–D0-9, which had 0% disc content) and M2 (specimens D4-10–D4-18, which had 4% disc content) groups, but the effect is reversed for specimens of the M3 (specimens D8-19–D8-27, which had 8% disc content) and M4 groups (specimens D12-28–D12-36, which had 12% disc content); the perfect bond strength is

90