PSI - Issue 70

C. Raghu Rami Reddy et al. / Procedia Structural Integrity 70 (2025) 223–230

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fiber dispersion, and matrix densification as influenced by the addition of fiber reinforcement and mineral admixtures. The flow chart in Fig. 1 depicts the general experimental methods used in this investigation.

Table 1. chemical composition details of cement and SCMs

Oxide composition

Metakaolin (%)

Fly Ash (%)

Silica Fume (%)

OPC (%)

SiO 2

20 – 25

50 – 60 30 – 40

35 – 60 15 – 30 4 – 10 1 – 12 0.5 – 2 0.5 – 5

85 – 97 0.5 – 1.5 0.5 – 2.0 0.2 – 1.0 0.1 – 0.5

Al 2 O 3 Fe 2 O 3 CaO MgO

4 – 8 2 – 4

1 – 2

60 – 67 0.5 – 4

0.1 – 2

<1 <2

LOI

<3

1 – 3

Table 2. Properties of raw materials

Specific Gravity

SEM Characteristics

Material

Fineness 320 m²/kg 380 m²/kg 450 m²/kg

Cement (OPC 53-grade)

3.15

Angular, rough particles (Ramachandran, 1981) Spherical particles (5 – 50 µm) (Zhang et al., 2023) Platy particles (1 – 10 µm) (Li et al., 2024) Fine spheres (<0.1 µm) (Chen et al., 2025)

Fly Ash (Class F)

2.2 2.6 2.2

Metakaolin Silica Fume Sand (River)

20,000 m²/kg

Fineness modulus 2.6 12 mm length, 0.04 mm diameter Not applicable (liquid) Not applicable (liquid)

2.65 0.91 1.02 1.08

Angular particles (50 – 500 µm)

PP Fibers

Smooth, cylindrical fibers (Zollo, 1997)

Foaming Agent

Forms spherical voids (50 – 500 µm) (ASTM International, 1997)

Superplasticizer (PCE)

Not applicable Not applicable

Water (Potable)

Not applicable

1.0

Table 3. Optimized CLC Mix Proportions with Density 1200 kg/m 3 Component REF(M1) FA10(M2) MK10(M3)

SF10(M4)

Cement (kg/m 3 ) Fly Ash (kg/m 3 )

400

360

360

360

— — —

40 — —

— 40 —

— — 40

Metakaolin (kg/m 3 ) Silica Fume (kg/m 3 )

Water (kg/m 3 )

180 582

180 582

180 582

180 582

Natural Sand (kg/m 3 ) Superplasticizer (kg/m 3 )

3

3

3

3

PP Fibres (kg/m 3 )

— 25

3.2

3.2

3.2

Foam (kg/m 3 @ 60 kg/m 3 )

25

25

25