PSI - Issue 67

3

Hwan Lee et al. / Procedia Structural Integrity 67 (2025) 107–114 Author name / Structural Integrity Procedia 00 (2024) 000 – 000

109

4 μ m

1 μ m

(a)

(b)

Fig. 1 SEM image of (a) nano metakaolin, and (b) CNT

exhibited a fibrous structure with diameters ranging from 10 to 50 nm and a length of about 10 μm , making it a 1D nanofiber with at least two outer dimensions in the nanoscale (see Fig. 1b). 1.2. Mixture proportions Three dosages were used for each nanomaterial. NMK was used to replace the cement content by 5 wt%, 7.5 wt%, and 10 wt%. CNTs were used on an addition basis at 0.01 wt%, 0.03 wt%, and 0.05 wt% relative to the cement weight. Table 1 and Table 2 show the mix proportions of mortar samples and paste samples. A water-to-binder (w/b) ratio of 0.45 was used for specimens prepared for compressive strength and resistivity; the w/b for the ASR specimens was 0.47. Table 1. Mix proportions of mortar samples for the ASR test Label Cement (g) Reactive Sand (g) NMK (g) CNT (g) PCE (ml) Water (ml) Control 100 225 0 0 0 47 NMK_5 95.00 225 5 0 0.3 47 NMK_7.5 92.50 225 7.5 0 0.4 47 NMK_10 90.00 225 10 0 0.5 47 CNT_0.01 100 225 0 0.01 0.06 47 CNT_0.03 100 225 0 0.03 0.12 47 CNT_0.05 100 225 0 0.05 0.18 47

Table 2. Mix proportions of mortar samples for compressive strength and resistivity tests Label Cement (g) Sand (g) NMK (g) CNT (g)

PCE (ml)

Water (ml)

Control NMK_5

100

225 225 225 225 225 225 225

0 5

0 0 0 0

0

45 45 45 45 45 45 45

95.00 92.50 90.00

0.3 0.4 0.5

NMK_7.5 NMK_10 CNT_0.01 CNT_0.03 CNT_0.05

7.5

10

100 100 100

0 0 0

0.01 0.03 0.05

0.06 0.12 0.18