Effect of Silica Fume and Fly Ash on Properties of ConcreteMixtures Using River Sand and Manufactured Sand

Abstract: This research studied on partial replacement of cement with silica fume (SF) and fly ash (FA) on the properties of high strength concrete. The maximum compressive strength of grade 40 observed as 59 MPa (12% higher compared to control mix), in grade 60 observed as 70 MPa (SF15%-14% higher compared to control mix) and in grade 80 observed as 96 MPa (SF 20% - river sand). The replacement of Ordinary Portland Cement with SF increases packing of particles in the concrete mix. As the compressive strengths of samples were increased with the inclusion of SF. FA mixtures displayed higher or similar workability compared to the control mix. The lowest compressive strength of G40 observed as 49 MPa (6% lower compared to control mix), in G60 observed as 51 MPa (FA 25%- 15% lower compared to control mix). Furthermore re-dosing was done to identify the behavior of manufactured sand (M-sand) in grade 40 and 60. That gave 51 MPa compressive strength to grade 40 and 69 MPa for grade 60.

Keywords: Fly ash, silica fume, high strength concrete, cost analysis.

1. INTRODUCTION

2. METHODOLOGY

2.1. Materials

Binding Agent-

Fine Aggregate-

Coarse Aggregate-

Water-

Admixtures

Table 1 Test variables

Mixes Replacement (%)

2.2. Test variables

Table 2 Concrete mix designs

Grade Cement Content(kg)

Fine Aggregate Content (kg)

Coarse Aggregate Content (kg)

Water Content(kg)

2.3. Testing

3. RESULTS AND DISCUSSION

Figure 2 Compressive Strength of Grade 60

Figure 3 Compressive Strength of Grade 80

Figure 1 Compressive Strength of Grade 40

Figure 4 Splitting Tensile Strength of Grade 40

3.2. Splitting tensile strength

3.3. Flexural Strength

Figure 5 Splitting Tensile Strength of Grade 60

Figure 6 Splitting Tensile Strength of Grade 80

Figure 9 Flexural Strength of Grade 40

Figure 8 Flexural Strength of Grade 60

Figure 7 Flexural Strength of Grade 80

3.4 Workability details

Figure 10 Grade 40 Workability Results Figure 11 Grade 60 Workability Results

3.5 Cost analysis

Table 3 Cost analysis

Grade% Cement

ReplacementPrice per 1m3

(LKR)

Compressive strength (MPa)

(28 days)

Grade 40 (River Sand)

Grade 40(M- Sand)

Grade 60 (M- Sand)

Grade 80 (River Sand)

Grade 80 (M-Sand)

4. CONCLUSIONS

5. ACKNOWLEDGEMENTS

7. REFERENCES