PSI - Issue 67

Dan Huang et al. / Procedia Structural Integrity 67 (2025) 61–79 Huang, D., Velay-Lizancos, M., Olek, J./ Structural Integrity Procedia 00 (2024) 000–000

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ensure an adequate level of workability and aid with the dispersion of nano-TiO 2 (Z. Li et al., 2018). A constant amount of HRWR was used in all mixtures.

Fig. 2. The gradation curves of coarse and fine aggregates. (Note: CA=coarse aggregate; FA=fine aggregate.)

Table 2. The physical properties of coarse and fine aggregates. Aggregates Maximum Particle Size, mm

Specific gravity (SSD)

Fineness Moduli

Absorption, %

Coarse aggregate Fine aggregate

25

3.34 2.87

2.61 2.74

2.28 1.97

9.5

Note: SSD = Saturated surface dry condition

Nano-TiO 2 admixture used in this study was obtained from the US Research Nanomaterials, Inc. Based on the information provided by the seller, the average particle size of the nano-TiO 2 particles was 18 nm and the material mostly contained anatase phase. Additionally, the purity level of the nano-TiO 2 particles was 99.9%, their specific surface area was 200 – 240 m 2 /g, and the density of the material was 0.24 g/cm 3 . Nano-silica used in this study was manufactured by Specification Products (brand name Element Five-E5). Two types of nano-silica were studied: E5 LFA and E5-IC. Both of these materials are proprietary products. Fig. 3(a) and (b) present the transmission electron microscopy (TEM) graphs for E5-LFA and E5-IC, respectively. As shown in Fig. 3, the nano-silica particles appear to have a size in the range of 5 to 20 nm.