Concrete Durability by Luis Emilio Rendon Diaz Miron & Dessi A. Koleva

Author:Luis Emilio Rendon Diaz Miron & Dessi A. Koleva
Language: eng
Format: epub
Publisher: Springer International Publishing, Cham

w/c

n-values

References

0.5

0.320

Stanish [48]

0.5

0.178

Zhuqing Yu [24]

0.45

0.264

Bamforth [23]

0.45

0.275, q = 0.22

Andrade [11]

0.45

0.236

Dalen [31]

0.45

0.182

Maes [49]

0.4

0.350

F. Presuel-Moreno [13]

4.4.4 Diffusion Coefficient

By considering the previously introduced theoretical background and employing the aging factor n as presented in the Table 4.1, the apparent diffusion coefficient as function of time can be predicted, using Eq. (4.3). Graphically this is presented in Figs. 4.9 and 4.10. Figure 4.9 depicts a comparison of the apparent diffusion coefficient (D ap) as derived from the obtained aging factors n in this study (curve “control 0.5”) and D ap as reported in literature for control conditions. As seen in the Fig. 4.9, there is a good agreement between the D ap values, predicted based on calculation from the aging factor n and these derived from direct measurements of apparent diffusion coefficient. This outcome can be further used to predict the influence of stray current flow on apparent diffusion coefficient of cement-based materials. Figure 4.10 depicts the evolution of D ap for the under current subgroups 100 mA/m2 and 1 A/m2 in comparison to the control group in this study. As expected, the apparent diffusion coefficient did not change significantly at early stages, which holds for both groups of w/c ratio of 0.5 and 0.35. A gradual decrease, however, was observed at later stages with decreasing the w/c ratio (i.e., D ap of w/c ratio 0.35 is lower than that of w/c ratio 0.5).

Fig. 4.9Prediction of apparent diffusion coefficient calculated using Eq. (4.3) based on aging factor (n), as derived from electrical resistivity records, compared to reported literature results

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