Issue 64

A. Abdo et alii, Frattura ed Integrità Strutturale, 64 (2023) 11-30; DOI: 10.3221/IGF-ESIS.64.02

for 120 s (low speed). The mixer is stopped for 30 s after. c) the remaining water and SP are added, then the mixer works at low speed for 180 s. d) the mixture is at a high mixing speed for 120 s. Samples were well covered with burlap that was submerged in water before. Samples were sprinkled twice with water every day for 28 days. Compression test on cubes (100*100*100 mm) for different types of concrete was performed at ages 7 and 28 days of curing in water. The compressive properties of materials have been set according to the ASTM C39/C39M-10 standard. Tab. 2 shows the compressive strength of different types of used concrete.

(a) (b) Figure 1: Hooked-end steel fiber. a) steel fiber set, b) fiber Dimension.

Steel fiber (%)

Silica fume

Sand 0-0.5mm

Sand 0-2 mm

Super plasticizer

Fine aggregate

Coarse aggregate

Cement

Water

NC

450 884 884 884

-

-

-

-

180 170 170 170

548

1279

0 0 1 2

UHPC

41 41 41

227.5 227.5 227.5

1090 1065 1045

45.5 45.5 45.5

0 0 0

0 0 0

UHPFRC1 UHPFRC2

Table 1: Mix proportion (kg/m 3 )

100

75

50

% Pass

25

0

0,01

0,1

1

10

100

1000

10000

Particle size (micro meter)

cement

silica fume

sand 0-0.5mm sand 0-2mm target

composite

Figure 2: The grading curves of the used materials and the target and final composition curve.

Cubic Compressive strength (F cu )

Mix ID

35

NC

105 125

UHPC

UHPFRC1 UHPFRC2

140 Table 2: Compressive strength after 28 days (MPa)

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