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Home arrow Engineering arrow Creep Behaviour in Cracked Sections of Fibre Reinforced Concrete: Proceedings of the International RILEM Workshop FRC-CREEP 2016

Statically Indeterminate Plate Test

In addition to the statically determinate beam tests, the long term behaviour of SFRC and PFRC plates on continuous support has been investigated (Table 4). The focus of this investigation is directed to the analysis of the long term behaviour of tunnel linings under rock pressure around an anchor bolt. For this purpose, a long term test setup is built so as to load cast panels according to EN14488-5 [3]. Per tested series, 3 FRC square plates of 600 mm x 600 mm x 100 mm are centrally loaded in a displacement controlled manner as shown in Fig. 2. The pre-cracking test is ended at a specified 5pc (Table 4) of the centre point of the panel. The maximum load and thus the relevant crack pattern are usually achieved at deflections from 2 to 3 mm. But while in some cases 2 mm deflection is sufficient to

Table 4 Overview of centrally loaded plate tests

Creep program

B1

B2

B3

Start program

September 2009

March 2012

April 2012

End program

September 2012

Ongoing

January 2013

Object size

W = 600 mm

W = 600 mm

W = 600 mm

H = 100 mm

H = 100 mm

H = 100 mm

Type of test

EN14488-5

EN14488-5

EN14488-5

F

creep

60 % Fr

40-60-80 % Fr

60 % Fr

Spc

3 mm

2 mm

3 mm

# specimens

12

6

6

# failed during test

3 PFRC

-

-

Concrete type

C3

C1

C1

Curing days

58-62 days

2 days

2 days

Fiber types

3D 65/35BG

3D 65/35BG

3D 65/35BG

3D 80/60BG

PF-73/65

PF-73/65

PF-90/40

Setup of EN14488-5 creep test method reach this level, a deflection of 3 mm is preferred

Fig. 2 Setup of EN14488-5 creep test method reach this level, a deflection of 3 mm is preferred. Otherwise the specimen could still be in the phase of initial cracking, not having developed the final crack pattern.

The load-deflection curve is recorded and Fr is registered. The deflection recovery was not measured. The plate is then moved to the permanent setup of a rigid steel square loading block having a contact outline of (100 ± 1) mm x (100 ± 1) mm and where Fcreep is applied, equivalent to 40-60 % of Fr. Fcreep in program B2 was adjusted over time up to 80 % Fr as shown in Fig. 7. The deflection is measured at regular intervals. 5creepm (Table 6) is, similarly to the beam tests, the average of the individually registered deflections due to creep at failure or last measured point. The fibres which are taken up in programs B2 and B3 are fibres commonly used in shotcrete applications. Specimens with 25 kg/m3 3D 65/35BG and 7 kg/m3 PF-73/65, were loaded with similar Fcreep as shown in Table 7.

Table 5 Overview of statically determinate beam tests

Program

Fiber type

Specimens

Dosage

Average test duration

^creep,m

kg/m3

% vol

days

x10-2 mm

A1

PF-48/48

3

4.55

0.49

1694

841

PF-83/50

3

4.55

0.49

764

947

3D 65/35BG

2

20

0.26

4318

195

A2

3D 45/30BG

1

30

0.38

1967

191

PF-80/54

1

6

0.65

674

874

PF-90/40

1

6

0.65

1966

401

A3

3D 65/60BG

3

40

0.51

719

28

5D 65/60BG

2

40

0.51

738

30

Program A1

Fig. 3 Program A1: 4-point bending on 150 mm x 50 mm x 500 mm at 50 % Fr (Spc = 5 mm)

Program A2

Fig. 4 Program A2: 3-point bending on 1500 mm x 870 mm x 40 mm at 60 % Fr (Spc = 3 mm)

Program A

Fig. 5 Program A: 3-point bending test (based on EN14651) at 60 % Fr (CMODpc = 0.5 mm)

Table 6 Overview of statically indeterminate plate tests

Program

Fiber type

Specimens

Dosage

Average test duration

^creep,m

kg/m3

% vol

days

mm x 10-2

B1

3D 80/60BG

3

25

0.32

890

119

PF-90/40

3

4.5

0.49

301

569

3D 80/60BG

3

40

0.51

880

166

3D 65/35BG

3

40

0.51

885

158

B2

3D 65/35BG

3

25

0.32

1392

111

PF-73/65

3

7

0.76

1385

274

B3

3D 65/35BG

3

25

0.32

281

43

PF-73/65

3

7

0.76

273

81

Program B1

Fig. 6 Program B1: EN14488-5 on 600 mm x 600 mm x 100 mm at 60 % Fr (Spc = 3 mm)

 
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