thThe 14 World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China

STUDY ON THE INFLUENCE OF THE FIBER ORIENTATION TO THE
MECHANICAL PERFORMANCE OF HPFRCC
12Tetsuo FUKUHARA , Toshiyuki KANAKUBO and Atsuhisa OGAWA3
1Graduate Student, Graduate School of Systems & Information Engineering,
University of Tsukuba, Ibaraki, Japan
2Associate Professor, Graduate School of Systems & Information Engineering,
University of Tsukuba, Ibaraki, Japan, Dr.E.
3Senior Engineer, Industrial Materials R&D Dept., Fibers and Industrial Materials Division,Kuraray Co.,Ltd., Tokyo, Japan
Email: t-fuku03@rcs.kz.tsukuba.ac.jp, kanakubo@kz.tsukuba.ac.jp, Atsuhisa_Ogawa@kuraray.co.jp
ABSTRACT :High Performance Fiber Reinforced Cementitious Composites, HPFRCC has been expected as new material
because the ductility on bending, tension, and shear behavior would be improved largely than ordinary concrete.
However, to give an expected performance, it is important to know how the fiber will be orientated anddistributed in the matrix. There are many indistinct point how fiber is oriented. This paper aims to present theinfluence of fiber orientation to the mechanical performance of HPFRCC.
In this study, one large specimen of HPFRCC is prepared with polyvinyl alcohol (PVA) fiber. Then one large
specimen is cut to small coupons and the mechanical performance of HPFRCC due to the influence of fiber is
examined by using the bending test and observation of cross section by mercury lamp. From the test result,number of fiber is related to the mechanical performance closely when coupon is cut on axial direction. The
number of fiber is increasing as close to the mold surface. As increased the number of fiber, the bending
performance increases. On the other hand, bending performance of coupon that is cut on perpendicular direction
is not related to the position of the coupons and number of fibers directly.
KEYWORDS:

HPFRCC, PVA fiber, Coupon, Bending Moment-Curvature curve, Mercury Lamp

1. INTRODUCTION
Recently, as the substitute of reinforced concrete, the research of High Performance Fiber Reinforced
Cementitious Composites, HPFRCC has been carried out. HPFRCC is the composite material with mixing fiberin mortar, and fibers bear the tension in substitution for reinforcing bar. For representative characteristic ofHPFRCC, under the condition of uniaxial tensile stress or the bending stress, HPFRCC shows multiple cracks.
Furthermore, it also shows that the stress increases after the first cracking, which is called as strain hardening or
deflection hardening. Therefore, HPFRCC is expected as new materials, because the ductility of bending,tension, and shear behavior would be improved largely than ordinary reinforced concrete as the seismicmembers.
However, the distribution and orientation of fibers is an important factor in terms of mechanical performance ofthe composite. In other words, the large difference of mechanical performance is shown when fibers are oriented
by axial and perpendicular direction of loading. In addition, it is difficult to confirm the distribution andorientation of fibers in the composite, there are many indistinct point how the fibers are oriented. In this study,
the influence of the fiber orientation to the mechanical performance of HPFRCC is examined by using thebending test and observation of cross section by mercury lamp.

thThe 14 World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China
2. OUTLINE OF SPECIMEN
2.1. Mix Proportion
The mix proportion of HPFRCC is shown in Table 1.The length is 12mm, diameter is 40μm, tensile strength is
1600MPa, and elastic modulus is 40GPa of polyvinyl alcohol (PVA) fiber is used. The fiber volume fraction is1.5%.
Table 1 The mix proportion of HPFRCC
Water
Fine aggregate

Unit quantity(kg/m3）380
484

Expansion agent

101.7

Thickening agent

1.91

CementFly ashShrinkage-reducing
admixture
High performance AE
water reducing agent

Unit quantity(kg/m3）576
291
205.782.2. Specimen
A large size specimen with 140mm in depth, 780mm in width and 1675mm in length and five prepared small
specimens that cross section is 60mm x 60mm and length is 350mm were prepared as HPFRCC. The specimens
were cured by stream at first day, and then mold are removed. After that the specimens left in atmosphericcuring.
Overall view of cutting for a large specimen is shown in Figure 1. To compare the influence of the cast direction,a large specimen is cut to three parts such as A, B and C by using the diamond cuter. Then, to compare theinfluence of cast, mold and cutout surface, part A and C is cut to 14 coupons in each part. The detailed view ofcutting in part A and C is shown in Figure 2. 4 coupons on axial direction (X-direction) and 3 coupons on
perpendicular direction (Y-direction) are cut from both upper and lower section. Part B is cut to 9 coupons. The
detailed view of cutting in part B is shown in Figure 3. 5 coupons on X-direction and 4 coupons on Y-direction
are cut from middle section. The total number of coupons is 37. The size of coupons is same as five small
prepared specimens that cross section is 60mm x 60mm and length is 350mm.

Figure 1 Overall view of cuttingthThe 14 World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China

Figure 2 Detailed view of cutting in Part A and C Figure 3 Detailed view of cutting in Part B
2.3. Specimen Identifications
The identification of coupon is shown in Figure 4. Cutting part is A, B and C that is shown in Figure 1. Cutting
section is that upper section as U, middle section as M and lower section as L. Cutting direction is on
X-direction and Y-direction from Figure 1. The position number is shown in Figure 2 and 3. In addition, theidentification of five prepared specimens is as 1-1 to 1-5.

Figure 4 Identification of coupon
3. OUTLINE OF LOADING TEST
3.1. Four-point Bending Test
Four-point bending test based on Method of Test for Bending Moment-Curvature Curve of Fiber-Reinforced
Cementitious Composites (JCI-S-003-2007) in Japan Concrete Institute (JCI) Standard is performed by using
2MN universal testing machine. However, specimen size is used as 60mm in depth, 60mm in width and 350mmin length instead of 100mm in depth, 100mm in width and 400mm in length. Outline of four-point bending test
is shown in Figure 5. The bending moment and curvature is calculated by using the following equation (3.1) and(3.2) to obtain the bending moment-curvature curve.

Figure 5 Four-point bending testth

The 14 World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China

P l⋅
2 3
ε 2 − ε1

M =

φ=
M:
P:
l:
φ:
ε 1, ε 2:d0:

d0(3.1)(3.2)

Bending moment ( kN・mm )Applied load ( kN )Span ( = 300mm )Curvature ( 1/mm )Strains calculated by dividing the measured displacements of upper and lower LVDTs by contact
length ( mm ) (elongation is defined as positive)
Distance between two LVDTs ( = 40mm )3.2. Cross Section Observation
It is known that PVA fiber absorbs the ultraviolet radiation and emits fluorescence. [1] Based on this principle,
mercury lamp is used to observe PVA fiber. Outline of the observation is shown in Figure 6.
The cross section is cut around close to the largest crack which occurred by four-point bending test, then theimage of cross section’s coupons is captured with a digital camera through a microscope by using mercury lamp.
The yellow cellophane sheet is used with mercury lamp to let PVA fiber emphasize the emission of light more.
The captured image of cross section is analyzed and mapped as two valued color that PVA fiber is to black dots
and cement is to white color by using image analysis software. An example of analyzed and mapped crosssection is shown in Figure 7. Finally, the black dots are counted as the number of fibers by using image analysis
software.

Figure 6 Outline of cross section observation

Figure7 An example of cross section(A1-U-X2)

4. Experimental Result
The list of test results is shown in Table 2. In this table, Mmax is the maximum bending moment, φmax is thecurvature at the maximum bending moment and Nf is the number of PVA fiber by counted on black dots. The
average of five prepared specimens’ Mmax and φmax is defined as Mmax,w and φmax,w, respectively. In addition,the average of five prepared specimens’ number of PVA fiber is defined as Nf,w.

thThe 14 World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China
Table 2 The list of test results
ID
1-1
1-2
1-3
1-4
1-5
A1-U-X0
A1-U-X1
A1-U-X2
A2-U-X3
A1-L-X0
A1-L-X1
A1-L-X2
A2-L-X3
B0-M-X1
B0-M-X2
B0-M-X3
B0-M-X4
B1-M-X5
C1-U-X0
C1-U-X1
C1-U-X2
C2-U-X3
C1-L-X0
C1-L-X1
C1-L-X2
C2-L-X3

Mmax
φmax(kN・m)(1/m)
0.327
0.390
0.445
0.142
0.412
0.280
0.440
0.242
0.400
0.171
0.126
0.008
0.159
0.011
0.218
0.100
0.391
0.288
0.250
0.126
0.300
0.237
0.347
0.228
0.381
0.246
No Data
0.221
0.089
0.318
0.232
0.378
0.166
0.355
0.212
0.164
0.086
0.110
0.007
0.185
0.056
0.258
0.083
0.272
0.245
0.292
0.242
0.319
0.151
0.427
0.334

Nf
6486
10345
7721
6293
8855
8388
6219
6824
10737
7918
5801
10046
9463
10992
7346
10057
11038
12784
8427
6934
70889856
9223
9699
11184
9348

Mmax
/ Mmax,w
Mmax,w
=
0.405
kN･ m
0.311
0.393
0.539
0.966
0.618
0.741
0.857
0.941
－
0.546
0.786
0.934
0.877
0.405
0.272
0.457
0.637
0.672
0.721
0.788
1.055

ID

Mmax
(kN・m)(1/m)

A1-U-Y1
A1-U-Y2
A2-U-Y3

0.247
0.276
0.194

0.132
0.124
0.011

6747
6566
5827

A1-L-Y1
A1-Ｌ-Y2
A2-L-Y3

0.112
0.142
0.245

0.040
0.162
0.045

5407
7045
4943

B0-M-Y1
B0-M-Y2
B0-M-Y3B0-M-Y4

0.073
0.083
0.072
0.062

0.065
0.004
0.077
0.096

4352
5882
6622
4979

C1-U-Y1
C1-U-Y2
C2-U-Y3

0.216
0.084
0.270

0.130
0.027
0.203

5795
6334
5975

C1-L-Y1
C1-L-Y2
C2-L-Y3

0.299
0.361
0.284

0.180
0.230
0.079

6303
4823
3368

φmax
/φmax,wφmax

Nfφmax,w
=
0.245
1/m
0.033
0.045
0.408
1.176
0.514
0.967
0.931
1.004
－
0.363
0.947
0.678
0.865
0.351
0.029
0.229
0.339
1.000
0.988
0.6161.363

4.1. Prepared Specimens

Bending moment（kN・m）

The bending moment and curvature curve is shown in Figure 8. Mmax,w is 0.405 kN·m, and φmax,w is 0.245 1/m.
In addition, the standard deviation of Mmax is 0.042 kN·m, standard deviation of φmax is 0.088 1/m. From theFigure 8, the deflection hardening behavior is recognized.
0.5

1-1
1-2
1-3
1-4
1-5

0.4
0.3
0.2
0.1
0

0.1

0.2

0.3

0.4

0.5

0.6

Curvature（1/m）

Figure 8 Bending moment – curvature curve of prepared specimens
4.2. Coupons on X-direction
4.2.1 Bending moment and curvature curve
The relationships between bending moment and curvature of coupon on X-direction in Part A and C are shownin Figure 9. From Figure 9, the deflection hardening behavior is observed well at lower section of Part A and C.
However, the deflection hardening behavior is little observed at upper section of Part A and C and lower
strength than lower section in both Part A and C is shown. Therefore, upper section of the maximum moment islower than the maximum moment of lower section.

th0.4
0.3
0.2
0.1
0

0.1

0.2

0.3

A1-U-X0
A1-U-X1
A1-U-X2
A2-U-X3
0.4
0.5

Curvature（1/m）

0.5
C1-U-X0
C1-U-X1
C1-U-X2
C2-U-X3

0.4
0.3
0.2
0.1
0

0.1

0.2

0.3

0.4

0.5

Bending moment（kN・m）

0.5

Bending moment（kN・m）

Bending moment（kN・m）

Bending moment（kN・m）

The 14 World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China

0.5
0.4
0.3
0.2

0.2

A1-L-X0
A1-L-X1
A1-L-X2
A2-L-X30.30.4
0.5

0.2

C1-L-X0
C1-L-X1
C1-L-X2
C2-L-X3
0.4
0.5

0.1
0

0.1

Curvature（1/m）

0.5
0.4
0.3
0.2
0.1
0

0.1

0.3

Curvature（1/m）
Curvature（1/m）
Figure 9 Bending moment-curvature curve of coupons on X-direction

4.2.2 Influence of mold surface
The distance from mold surface to the center of each coupon and maximum moment (Mmax) relationship in Part
A, B and C is shown in Figure 10. The distance from mold surface to center is calculated from each center ofcoupons. The maximum moment of coupon decreases with increases the distance from the mold surface tocenter of each coupon at Part A and C. However, in part B, the maximum moment of coupon increases around
100mm from mold surface once, and then decreases with increases the distance.
The distance from mold surface to center of each coupon and number of PVA fiber (Nf) relationship in Part A, B
and C is shown in Figure 11. The number of PVA fiber decreases with increases the distance from mold surface.
This result has same tendency described in Figure 10. Especially in Part C, the maximum moment increases
after the distance from mold surface is around150mm, as same as number of PVA fiber in Figure 11. Therefore,
it can be recognized that the number of PVA fiber is related closely with the maximum moment for each coupon.
Moreover, the reason why maximum moment increases as the mold surface comes to a close can be recognizedthat PVA fiber would be concentrated around mold surface and orientated as parallel to mold surface.

Mmax（kN・m）

0.5

0.5

0.5

0.4

0.4

0.3

0.3

0.3

0.2

0.2

0.2

0.1

0.1

PartA upperPartA lower

0.40100200300

400 0PartB middle
100200300

PartC upper
PartC lower

0.1
400 0100200300

Distance from mold surface to center of each coupon (mm)Figure 10 Maximum moment (Mmax) and distance from mold surface relationships

400

thThe 14 World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China

15000

15000

10000

10000

10000

5000

5000

Nf

15000

5000

0

PartA upper
PartA lower
100200300

PartC upper
PartC lower

PartB middle
4000100200300

4000100

200300400

Distance from mold surface to center of each coupon (mm)Figure 11 Number of PVA fiber (Nf) and distance from mold surface relationships
4.2.3 Maximum moment and number of PVA fiber relationshipThe ratio of maximum moment (Mmax/Mmax,w) and the ratio of number of PVA fiber (Nf/Nf,w) in Part C is shownin Figure 12 and the ratio of curvature (φmax/φmax,w) and the ratio of number of fiber (Nf/Nf,w) in Part C is shownin Figure 13. Nf,w is 7940. The ratio is defined as that the maximum moment or curvature of each coupon isstandardized by Mmax,w or φmax,w. The ratio of number of PVA fiber is same calculation as the ratio of maximum
moment or curvature. From Figure 12 and 13, higher ratio of maximum moment or curvature has higher ratio of
number of PVA fiber basically. However, some results show that even if higher ratio of number of PVA fiber, theratio of maximum moment or curvature has lower ratio at upper section in Part C. This result can be recognizedthat the influence of polishing and cleaning on cast surface is very large.
1.5

φmax/φmax,w

Mmax/Mmax,w

1.5
10.5

00.5

1

1.5

210.50

0.5

1

1.5

2

Nf/Nf,w
Nf/Nf,w
C1-U-X0
C1-U-X1
C1-L-X0
C1-L-X1
C1-U-X2
C2-U-X3
C1-L-X2
C2-L-X3Figure 12 The ratio of Mmax and Nf Figure 13 The ratio ofφmax and Nf

4.3. Coupons on Y-direction
The bending moment and curvature curve of coupon in Part A and C on Y-direction is shown in Figure 14. The
maximum moment and curvature at the maximum moment on coupon in upper section is lower than those inlower section by compared at same position number. This result shows same trend as the result of coupon onX-direction. From Table 2, the result of curvature at maximum moment of coupon on Y-direction is smaller thanthose on X-direction in general. In addition, position number is not related as the result of the maximum
moment or curvature. The result of coupon on Y-direction is varying widely. The reason can be recognized that
PVA fiber has tendency to be orientated as parallel at the cross section of coupon on Y-direction. PVA fiber ofthe coupon on X-direction is not related to mechanical performance for Y-direction coupons directly. Moreover,number of PVA fiber of the coupon in Y-direction is also not related to the test result such as maximum moment
or curvature directly.
In addition, the number of PVA fiber of coupon on Y-direction is almost 2/3 of the average number of PVA fiberof coupon on X-direction in general.

thA1-U-Y1
A1-U-Y2
A2-U-Y3

0.4
0.3
0.2

0.3

0.1

0.1

0.2

0.3

0.4

0.5

Curvature（1/m）

0.5
C1-U-Y1
C1-U-Y2
C2-U-Y3

0.4
0.3
0.2
0.1
0A1-L-Y1
A1-L-Y2A2-L-Y3

0.4

0.2

0.1
0Bending moment（kN・m）

0.5

0.5

0.1

0.2

0.3

0.4

0.5

Bending moment（kN・m）

Bending moment （kN・m）

Bending moment（kN・m）

The 14 World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China

00.1

0.2

0.3

0.4

Curvature（1/m）

0.5

0.5

C1-L-Y1
C1-L-Y2
C2-L-Y3

0.4
0.3
0.2
0.1
0

0.1

0.2

0.3

0.4

Curvature （1/m）
Curvature（1/m）
Figure 14 Bending moment-curvature relationships on Y-direction

0.5

5. CONCLUSION
In this study, five prepared specimens and 37 coupons are subjected to four-point bending test and observationof cross section using mercury lamp are carried out. The main parameters for coupons are cutting part, direction
and position from the mold surface. From the test result, the followings are summarized.
(1) It is confirmed that the maximum moment increases with close to mold surface on coupon in X-direction.
However, the result of coupon in Y-direction does not show same tendency as in X-direction.
(2) The number of PVA fiber is related to mechanical performance of coupon closely in X-direction.
(3) In upper section of casting direction, some coupon has lower rate of maximum moment or curvature at themaximum moment even if they have higher number of PVA fiber.
REFERENCES
1. Torigoe, S., Saito, T., Horikoshi, T., Hamada. T. and Ogawa, A. (2002). Study on Evaluation Method for
PVA fiber Distribution in Engineered Cementitious Composite. JCI International Workshop on Ductile
Fiber Reinforced Cementitious Composite.