令和6年度土木学会全国大会第79回年次学術講演会
第V部門
2024

年9月5日(木) 11:10 ~ 12:30

C306(川内北キャンパス講義棟Ｃ棟)

短繊維補強コンクリート（材料）(2)
座長：佐々木 亘（三井住友建設）
12:00 ~ 12:10[V-389] Uniaxial Tension Test for Fiber-Reinforced Cementitious Composite
with Thin Fiber、張 航1、金久保 利之1 (1. 筑波大学)
キーワード：FRCC、PVA、単軸引張試験、架橋則*TIAN WEICHAO 1

本研究では,繊維配向の影響を除いた繊維補強セメント複合材料 (FRCC)の引張特性を評価するために,細径短繊維を用いたFRCCの単軸引張試験を行い,実験結果をトリリニア架橋モデルによる計算結果と比較した。実験結果は,繊維破断の可能性を考慮した計算結果に良く適合することを示した。

© 2024 Japan Society of Civil Engineers- V-389 -V-389Japan Society of Civil Engineers 2024 Annual Meeting

Uniaxial Tension Test for Fiber-Reinforced Cementitious Composite with Thin Fiber
学生会員 ○Weichao Tian

筑波大学

学生会員

Hang Zhang

筑波大学

正会員

Toshiyuki Kanakubo

114.56 N and 107.79 N, respectively, and the average tensile
strength of the experiment is 2.54 N/mm2. From this table, itis evident that the experimental data have large discrepancies,
which may be attributed to the small size of the experimental
section.
Table 1 Mixture proportion of PVA-FRCC (Vf = 2%)
Unit weight (kg/m3)
WCFAS
Fc36-2%0.390.30
380678291484
Vf: fiber volume fraction; C: high early strength Portland cement;
FA: fly ash type II; S: silica sand; W: water;
Fiber: polyvinyl alcohol (PVA), diameter 0.1mm, length 12mm
Series

W/B

FA/B

Fig. 1 Dimension of specimens (Unit: mm)Table 2 Compressive strength test result
Series
Fc36-2%Average

Averagecompressive strength

elastic modulus(N/mm2)(kN/mm2)

49.1

19.2

120
12367100
Load (N)

1. INTRODUCTION
Fiber-reinforced cementitious composite (FRCC) is acement-based composite material incorporating short fibers
to enhance its tensile property. To clarify the pullout behaviorof fibers, it is necessary to perform a direct pullout test on
single fiber embedded in the matrix [1]. However, conducting
direct pullout tests on micro-diameter fibers can bechallenging due to handling difficulties. Therefore, in thisresearch, a uniaxial tension test was conducted on FRCC toevaluate the pullout behavior of thin fiber, while excluding
the influence of fiber orientation.
2. EXPERIMENT OVERVIEW
Ten specimens were prepared following the mixture
proportion of PVA-FRCC presented in Table 1. The
dimension of specimens, as shown in Fig. 1, has a length of
30 mm and a cross-sectional area of 5 mm × 5 mm at the target
test region. The employed specimen dimension design
method ensures approximately consistent fiber orientation
within the specimen, which excluding the influence of fiber
orientation on tensile property. The uniaxial tension test wasconducted using an electronic system universal testingmachine with a capacity of 200 N and a load speed of 1
mm/min. Additionally, a compression test withφ100 mm ×200 mm cylinder test pieces was conducted.
3. TEST RESULTS
3.1 Compression test
The compressive strength experimental result is presented
in Table 2. The average compressive strength is 49.1 N/mm2,and the average elastic modulus is 19.2 kN/mm2.
3.2 Uniaxial tension test
Ten specimens were prepared for testing. Three specimens
were excluded due to fractures during demolding, and two
specimens developed cracks before loading. During testing,specimen 1, 2, and 3 showed one crack, while specimen 6 and7 showed two cracks. The tensile load-head displacement
relationship obtained from the uniaxial tension test is shownin Fig. 2, excluding specimen 4 and 5, which showed cracks
before the experiment. According to the figure, specimen 3and specimen 6 show better experimental results compared tothe others. Therefore, for the following comparison with thecalculation, the experimental data of specimen 3 andspecimen 6 were used.
Table 3 gives the tensile properties of the specimens
obtained from the experiment. The table shows that themaximum tensile loads of specimen 3 and specimen 6 are筑波大学

806040200024Head displacement (mm)Fig. 2 Tensile load-head displacement relationship

Keywords FRCC, PVA, Uniaxial tension test, Bridging lawAddress〒305-8573 茨城県つくば市天王台 1-1-1 筑波大学 TEL 029-853-5045© Japan Society of Civil Engineers- V-389 -6

V-389Japan Society of Civil Engineers 2024 Annual Meeting

4. CALCULATION OF BRIDGING LAW
4.1 Method of calculation
In this research, the only factor affecting the fiber pullout
behavior is the embedded length of individual fiber since theinfluence of fiber orientation has been eliminated, as shownin Fig. 3. Therefore, the calculated bridging force can beobtained using Equation (1) with the trilinear bridging model
shown in Fig. 4 [2] and fiber rupture. The fiber rupture
probability (Pr) is a function of n. In this research, n is set to
be 1000 and Pr is assumed to be 0.006.

HD atmaxload(mm)Averagetensilestrength(N/mm2)

12
3
67

67.94
13.26
114.56107.79
59.53

27.96
26.26
28.34
29.92
28.08

2.43
0.50
4.04
3.60
2.12

0.464
0.309
0.621
0.738
0.930

2.54

HD: head displacement(1)

𝑃 = 𝑓(𝑛)Fbridge: bridging force; Fi(lb): pullout force of single fiber
Pr: fiber rupture probability; lb: embedded length
lf: fiber length; n: assumed number for calculation
4.2 Monte Carlo simulation
In this calculation method, the results vary depending on
which fibers with different embedded lengths rupture.
Therefore, Monte Carlo simulation (MCS) was used toanalyze the dispersion. A total of 600 trials were conducted,
as shown in Fig. 5. The x-axis represents the number of trials,
and the y-axis represents the bridging strength (=maximumbridging force) of each calculation trial. The bridging forcecrack width relationships for the cases of maximum,minimum, and average strength are shown in Fig. 6. The
maximum bridging strength is 119.98 N, the minimum is103.66 N and the average is 112.59 N in this MCS, with astandard deviation (SD) of 2.87 N.
Fig. 7 shows the comparison of experimental results withcalculated results. The red line in Fig. 7 represents the averagerelationship of 600 trials which is the same line as in Fig. 6.
The figure shows that the calculated result is in good
agreement with the experimental results.
5. CONCLUSION
A uniaxial tension test was conducted on FRCC to evaluate
the pullout behavior of thin fiber excluding the influence offiber orientation. The calculated results were compared to theexperimental results, and it was determined that the trilinear
bridging model provided a better fit to the experimental data,taking into consideration of the fiber rupture probability.
ACKNOWLEDGEMENTS
PVA fiber was provided by Kuraray Co., Ltd.
REFERENCES[1] 浅野浩平，金久保利之：高性能繊維補強セメント複合材料における短繊維の付着性状に関する研究：その1:PVA 単繊維の付着実験，AIJ 大会梗概集，821-822，2010.
[2] Toshiyuki Kanakubo, et al.: Influence of Fiber Orientation
on Bridging Performance of Polyvinyl Alcohol FiberReinforced Cementitious Composite, Materials Journal,
113(2), 131-141, 2016.

© Japan Society of Civil Engineers

Tensilestrength(N/mm2)- V-389 -Fig. 3 Calculation modelFig. 4 Bridging model[2]130SD: 2.87N

Bridging strength (N)/𝐹 (𝑙 ) (𝑃 > 𝑃 )(𝑃 ≤ 𝑃 )0

Crosssectionalarea(mm2)

120
110

Average strength
Maximum strength
Minimum strength

100900100200 300 400
Number of trials

500600Fig. 5 Calculation results in MCS
120
Bridging force (N)=∑No.

Maximumload(N)Average strength
Maximum strength
Minimum strength

10080
6040200024
Crack width (mm)6Fig. 6 Bridging force-crack width relationship
120
Average of calculated results
36100
Load (N)𝐹

Table 3 Tensile properties

806040200024Crack width (mm)6Fig. 7 Comparison of experiment and calculation