PSI - Issue 73

Sushant Chaudhary et al. / Procedia Structural Integrity 73 (2025) 19–26 Pratanu Ghosh / Structural Integrity Procedia 00 (2025) 000–000

25

7

Table 2: Strength estimation using optimum Q-value vs. adopted Q-value (37500 J/mol) for 90 TII-V/ 10 Z Day Actual Strength (MPa) Strength using optimum Q-value (MPa)

Strength using 37500 J/mol (MPa)

% Difference

1 3 7

9.79

11.51 20.89 28.20 34.40 40.68

11.44 20.81 28.07 34.25 40.49

0.58 0.40 0.44 0.43 0.48

21.51 30.61 34.68 38.47

14 28

4.3. Other Strength Estimation Functions Other functions (hyperbolic and exponential) are mentioned in section 3.2.3. were also employed to predict the strength of all the mixtures. The values for constants as mentioned in equations (3), (4), and (5) were determined using the least-squares curve fitting to the strength-maturity curve. These functions proved to be a better alternative to the logarithmic function, providing better accuracy as shown in Figures 5 and 6. Comparatively, the Exponential function produced the least error (< 10% except for one mixture), followed by the Hyperbolic (< 10% with few outliers) and Logarithmic (< 15% with few outliers). Hyperbolic and Exponential functions have similar Inter Quartile Range (IQR) and produce almost identical curves. In contrast, the logarithmic function obtained from S-M relationships tends to overestimate the later-day strength for most of the mixtures, as the estimated value keeps increasing with maturity, as shown in Figure 6.

10.00 12.00 14.00 16.00 18.00

0.00 2.00 4.00 6.00 8.00

Error %

Logarithmic

Hyperbolic

Exponential

Figure 5: Box and whisker plot for Error Percentage using all functions for all mixtures

0 10 20 30 40 50 60

0

100

200

300

400

500

600

Compressive Strength (MPa)

Equivalentage (hrs)

Actual-ternary Actual-control

Hyperbolic-ternary Hyperbolic-control

Exponential-ternary Exponential-control

Logarithmic-ternary Logarithmic-control

Figure 6: Actual vs. Estimated Compressive Strength for 100 TII-V(control) and 70 TII-V/ 20 Z/ 10 M (ternary) using different Functions