Table 5 Optimal design of HPFRCC mixtures

Design variables

Cement-to-binder ratio

14.4

25.0

25.0

11.8

16.1

16.1

11.8

24.9

25.0

Fly ash-to-binder ratio

27.1

28.4

28.4

20.5

30.8

30.8

27.2

27.0

28.4

Slag-to-binder ratio

7.2

7.2

7.3

7.5

6.8

6.8

6.6

7.4

7.1

Rice husk-to-binder ratio

5.2

9.5

9.4

6.0

17.2

17.2

5.4

16.9

9.3

Limestone-to-binder ratio

40.4

7.2

7.2

43.1

9.0

9.0

43.1

1.6

7.2

Metakaolin-to-binder ratio

4.7

4.9

4.9

9.4

12.5

12.5

3.8

5.1

4.9

Silica fume-to-binder ratio

1.0

17.0

16.8

0.3

6.7

6.7

0.5

16.3

16.8

Sand-to-binder ratio

0.8

0.7

0.8

1.3

0.6

0.6

1.4

0.4

1.4

Water-to-binder ratio

0.2

0.3

0.2

0.2

0.2

0.2

0.2

0.2

0.1

Superplasticizer content (%)

2.0

1.9

1.3

2.0

2.6

2.6

1.8

1.9

1.4

Fiber volume (%)

2.7

2.7

2.8

1.7

2.7

2.7

2.6

2.7

2.7

Fiber length (mm)

18

12

11

27

12

12

27

12

27

Fiber diameter (μm)

24

17

17

40

16

16

40

17

40

Elastic modulus of fibers (GPa)

100

6

6

200

6

6

200

6

200

Fiber type

PE¹

PP²

PP

Steel

PP

PP

Steel

PP

Steel

Output variables

Compressive strength (MPa)

59.1

62.5

67.3

93.1

103.3

103.2

70.9

114.1

102.6

First crack stress (MPa)

4.8

4.9

5.1

5.6

5.7

5.7

4.9

5.0

5.3

Ultimate tensile strength (MPa)

16.6

14.0

17.2

9.4

10.0

10.0

14.1

11.6

13.2

Ultimate tensile strain (%)

6.0

7.1

4.2

8.5

10.0

10.0

6.1

4.2

8.0

Carbon footprint (kg/m³)

745

1142

1207

895

1943

1990

1010

2249

1485

Cost (USD/m³)

633

456

458

872

566

579

1143

610

1292

Sustainability index

0.89

0.87

0.84

0.7

0.54

0.51

0.5

0.41

0.25