PSI - Issue 70

C. Raghu Rami Reddy et al. / Procedia Structural Integrity 70 (2025) 263–270

267

2. Results and Discussion

Compressive, split tensile, and flexural strength tests were used to assess the mechanical performance of CLC mixtures at 7, 14, and 28 days. The data, reported in Table 2, clearly illustrate that strength values increased with density and cure time across all mix types. Table 2. Compressive, Split tensile and flexural strengths of the CLC for varying densities of different mixes Mix Type Density (kg/m³) Compressive strength (MPa) Split Tensile strength (MPa) Flexural strength (MPa) 7D 14D 28D 7D 14D 28D 7D 14D 28D

800

2.5 3.8

3.8

5.8 8.5

0.3 0.6 0.6 0.4 0.7 0.5 0.8 1.1 0.6 0.9 1.3 1

0.6

1

0.7 1.1 1.8 0.9 1.5 1.5 2.2 1.2 1.7 2.5 2 1

1.2 1.8 2.8 1.4 2.2 1.5 2.2 3.2 1.8 2.5 3.5 3

1.5 2.5 3.8 1.8

Sand Based

1000 1200

6

1

1.4 1.8 1.1 1.6 1.2 1.8 2.2 1.3 2

5

8.2 4.2 6.5 8.2 4.5 6.8 8.5 4.8 7.2

11.5

1.3 0.7 1.1 1.5 0.8 1.2 1.6 0.9 1.3

800

2.7 4.2 5.5 4.5 5.8 3.2 4.8 6.2 3

6.2

M-Sand Mix

1000 1200

9

3

11.5

4.2

800

6.8 9.5

2 3

Copper Slag

1000 1200

12

4.5 2.5 3.5

800

7.2

Multi Fiber

1000 1200

10

2

9

12.5

2

2.4

5

2.1 Compressive Strength Multi-fiber mixes showed the highest compressive strength across all densities and curing periods, reaching 12.5 MPa at 28daysfor 1200kg/m³, followed by copper slag (12.0MPa) and M-sand (11.5MPa) mixes. Strength gains from 7 to 28 days indicate effective hydration and the reinforcing effect of fibers and denser aggregates as per ASTM C496 (2017). 2.2 Split Tensile Strength Tensile strength increased with both density and curing age. The multi-fiber mix again performed best (2.4 MPa at 1200kg/m³, 28days), with copper slag (2.2MPa) and M-sand (2.0MPa) also out performing sand-based mixes as per ASTM C78 (2018). 2.3 Flexural Strength For all combinations, flexural strength rose as density and cure time increased. The multi-fiber blend demonstrated the value of fibre synergy in improving bending resistance by achieving the greatest flexural strength of 5.0 MPa at 28 days for 1200 kg/m³.. Copper slag and M-sand mixes followed with strengths of 4.5 MPa and 4.2 MPa respectively. These results confirm the significant role of fiber reinforcement and alternative fine aggregates in improving the ductility and post-crack behaviour of CLC.