PSI - Issue 70

Rupankar Chakraborti et al. / Procedia Structural Integrity 70 (2025) 279–286

284

Table 4. Mix proportions for Trial 3.

Raw Ingredient

Quantity adopted for 1m 3 of concrete mix ( kg/m 3 )

Cement

258.8kg/m 3 43.1kg/m 3 129.4kg/m 3 155.25kg/m 3 615.86kg/m 3

Silica Fume

GGBFS

Water

Fine aggregate Coarse aggregate Chemical admixture

1161.24 kg/m 3 (CA1,CA2)

2.1563 kg/m 3

Cement

: FA : 2.4

:

CA

:

Water

1

:

4.5

:

0.4

Table 5. Mix proportions for Trial 4.

Raw Ingredient

Quantity adopted for 1m 3 of concrete mix ( kg/m 3 )

Cement

194.1kg/m 3 64.7 kg/m 3 172.5 kg/m 3 155.25kg/m 3 615.86 kg/m 3

Silica Fume

GGBFS

Water

Fine aggregate Coarse aggregate Chemical admixture

1154.17 kg/m 3 (CA1,CA2)

2.1563 kg/m 3

Cement

:

FA

: CA : 5.9

:

Water

1

:

3.2

:

0.4

5. Results and Discussion The compressive strengths of concrete obtained on different specimens and strengths were measured for 7 days, 14 days and 28 days respectively. The variations of compressive strengths for various concrete specimens were more for cement replaced samples rather than the normal control mix. In the entire concrete specimen various % of GGBFS and SF replacement is done along with 1% Super plasticizer. The following discussions are based on 7-days curing of normal mix and cement replaced sample mix. The compressive strength values for control mix CM40 (target strength 40 MPa) possess strength values of 16.448 MPa as the mean strength (nearly 41.12% of the target strength). Dissimilar trends were observed for CM40/BFS20/SF5 (specimen with 20% GGBFS and 5% SF replacement b/w of cement), CM40/BFS30/SF10 (specimen with 30% GGBFS and 10% SF replacement b/w of cement), CM40/BFS40/SF15 (specimen with 40% GGBFS and 15% SF replacement b/w of cement). For the specimen CM40/BFS20/SF5, the mean compressive strength was obtained as 26.59 MPa, achieved 66.47 % of the target strength. The specimen CM40/BFS30/SF10 achieved a mean compressive strength of 27.26 MPa, hence achieving 68.15% of target strength. The specimen CM40/BFS40/SF15 achieved strength of 26.37MPa, achieving 65.92% of target strength. Table 6. Compressive strength on 7 days curing SPECIMEN COMPRESSIVE CUBE STRENGTH(MPa) DESIGNATION (Age of curing – 7 days) %BFS+ %SF Spec1 Spec2 Spec3 Mean CM40/BFS0/SF0 0 16.7 15.6 17.1 16.4 CM40/BFS20/SF5 25 28.7 25.3 25.8 26.6 CM40/BFS30/SF10 40 27.1 26.7 28.0 27.3 CM40/BFS40/SF15 55 26.4 26.5 36.6 29.8