PSI - Issue 70

M. Vignesh et al. / Procedia Structural Integrity 70 (2025) 650–657

653

4.Results and discussion 4.1 Strength activity index (SAI)

The compressive strength for the control mix is 27.22 MPa and 31.47 MPa at 7 and 28 days respectively. Similarly the compressive strength results of 20% replacement of cement by CDW and WFS are 18.76 MPa, 22.42 MPa, 19.94MPa and 22.39 MPa at 7 and 28 days respectively. SAI for samples containing CDW replacement was 68.9% and 71.24%, SAI for samples containing WFS replacement was 73.26% and 71.14% rat 7 and 28 days respectively. Results show that both CDW and WFS do not possess pozzolanic activity as per (ASTM C618-22, 2022)

4.2 Compressive strength Test

Compressive strength values of all the mixes have been listed in Table 1. Fig 3 depicts the compressive strength of all mixes. Mix FC60WM5 containing 60% Fly ash, 20% WFS, 5% WMP and 15% lime showed the peak compressive strength of 9.13 MPa. Mix CD50WM15 made up of 50% CDW, 20% WFS, 15% WMP and 15% lime showed the least compressive strength of 0.283 MPa.

Table 1. Compressive strength of all mixes

Sl.No

MIXID

CDW (%)

FC (%)

WFS (%)

WMP (%)

Lime (%)

28 days Compressive Strength (MPa)

1. 2. 3. 4. 5. 6. 7. 8. 9.

FC60MS20 FC70MS20 FC60WS20 FC70WS20 FC60WM20 FC60WM15 FC60WM10 FC60WM5 FC50WM5 FC50WM10 FC40WM10 FC40WM5 FC30WM5 FC30WM10

60 70 60 70 60 60 60 60 50 50 50 40 40 30 30 30 50

20(M-sand) 20(M-sand)

20 10 20 10

3.35

5.0

20 20 20 20 20 20 30 20 20 20 20 20 20 10 30 20 10

8.35 6.59 1.25 5.57 8.63 9.13 7.29 4.39 5.19 2.49 5.88 4.38 7 5.7

20 15 10

5

10 15 15 10 15 10 15 15 10 10 10 15 15

5 5

10. 11. 12. 13. 14. 15. 16. 17. 18. 19.

10 10 20 20 30 30 40

10

CD10FC50WM5

5

10

5 5

10 10 10 15 15

CD40FC30WM10 FC50WS30WM10

3.4

CD50WM15 FC30WM15

50 30

0.283

30

1.96