Experimental research on mechanical properties of desert sand steel-PVA fiber engineered cementitious composites
An orthogonal experimental design method involving five-factor and four-level is adopted for the mix design of Desert Sand Steel-PVA fiber ECC. The effect of each level on Mechanical properties of ECC and the difference of Mechanical properties between each level is analyzed. The influence of differ...
Saved in:
| Published in: | Functional Materials |
|---|---|
| Date: | 2017 |
| Main Authors: | , , , |
| Format: | Article |
| Language: | English |
| Published: |
НТК «Інститут монокристалів» НАН України
2017
|
| Subjects: | |
| Online Access: | https://nasplib.isofts.kiev.ua/handle/123456789/136851 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Journal Title: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Cite this: | Experimental research on mechanical properties of desert sand steel-PVA fiber engineered cementitious composites / Che Jialing, Li Quanwei, Lee Minggin, Wang Dan // Functional Materials. — 2017. — Т. 24, № 4. — С. 584-592. — Бібліогр.: 15 назв. — англ. |
Institution
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
nasplib_isofts_kiev_ua-123456789-136851 |
|---|---|
| record_format |
dspace |
| spelling |
Che Jialing Li Quanwei Lee Minggin Wang Dan 2018-06-16T16:57:40Z 2018-06-16T16:57:40Z 2017 Experimental research on mechanical properties of desert sand steel-PVA fiber engineered cementitious composites / Che Jialing, Li Quanwei, Lee Minggin, Wang Dan // Functional Materials. — 2017. — Т. 24, № 4. — С. 584-592. — Бібліогр.: 15 назв. — англ. 1027-5495 DOI: https://doi.org/10.15407/fm24.04.584 https://nasplib.isofts.kiev.ua/handle/123456789/136851 An orthogonal experimental design method involving five-factor and four-level is adopted for the mix design of Desert Sand Steel-PVA fiber ECC. The effect of each level on Mechanical properties of ECC and the difference of Mechanical properties between each level is analyzed. The influence of different experimental factors is discussed, which includes water-binder ratio, fly ash substitution rate, desert sand substitution rate, proportion of PVA fiber and proportion of steel fiber. The experimental results indicate that water-binder ratio and fly ash substitution rate are the most principal and significant influencing factors on the compressive strength of ECC, regardless of age. Steel fiber is conducive to development of splitting tensile strength; PVA fiber is conducive to the development of flexural strength. High strength ECC can be prepared when the desert sand substitution rate is high. As the raw material of ECC, river sand can be 90% replaced by desert sand. en НТК «Інститут монокристалів» НАН України Functional Materials Characterization and properties Experimental research on mechanical properties of desert sand steel-PVA fiber engineered cementitious composites Article published earlier |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| title |
Experimental research on mechanical properties of desert sand steel-PVA fiber engineered cementitious composites |
| spellingShingle |
Experimental research on mechanical properties of desert sand steel-PVA fiber engineered cementitious composites Che Jialing Li Quanwei Lee Minggin Wang Dan Characterization and properties |
| title_short |
Experimental research on mechanical properties of desert sand steel-PVA fiber engineered cementitious composites |
| title_full |
Experimental research on mechanical properties of desert sand steel-PVA fiber engineered cementitious composites |
| title_fullStr |
Experimental research on mechanical properties of desert sand steel-PVA fiber engineered cementitious composites |
| title_full_unstemmed |
Experimental research on mechanical properties of desert sand steel-PVA fiber engineered cementitious composites |
| title_sort |
experimental research on mechanical properties of desert sand steel-pva fiber engineered cementitious composites |
| author |
Che Jialing Li Quanwei Lee Minggin Wang Dan |
| author_facet |
Che Jialing Li Quanwei Lee Minggin Wang Dan |
| topic |
Characterization and properties |
| topic_facet |
Characterization and properties |
| publishDate |
2017 |
| language |
English |
| container_title |
Functional Materials |
| publisher |
НТК «Інститут монокристалів» НАН України |
| format |
Article |
| description |
An orthogonal experimental design method involving five-factor and four-level is adopted for the mix design of Desert Sand Steel-PVA fiber ECC. The effect of each level on Mechanical properties of ECC and the difference of Mechanical properties between each level is analyzed. The influence of different experimental factors is discussed, which includes water-binder ratio, fly ash substitution rate, desert sand substitution rate, proportion of PVA fiber and proportion of steel fiber. The experimental results indicate that water-binder ratio and fly ash substitution rate are the most principal and significant influencing factors on the compressive strength of ECC, regardless of age. Steel fiber is conducive to development of splitting tensile strength; PVA fiber is conducive to the development of flexural strength. High strength ECC can be prepared when the desert sand substitution rate is high. As the raw material of ECC, river sand can be 90% replaced by desert sand.
|
| issn |
1027-5495 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/136851 |
| citation_txt |
Experimental research on mechanical properties of desert sand steel-PVA fiber engineered cementitious composites / Che Jialing, Li Quanwei, Lee Minggin, Wang Dan // Functional Materials. — 2017. — Т. 24, № 4. — С. 584-592. — Бібліогр.: 15 назв. — англ. |
| work_keys_str_mv |
AT chejialing experimentalresearchonmechanicalpropertiesofdesertsandsteelpvafiberengineeredcementitiouscomposites AT liquanwei experimentalresearchonmechanicalpropertiesofdesertsandsteelpvafiberengineeredcementitiouscomposites AT leeminggin experimentalresearchonmechanicalpropertiesofdesertsandsteelpvafiberengineeredcementitiouscomposites AT wangdan experimentalresearchonmechanicalpropertiesofdesertsandsteelpvafiberengineeredcementitiouscomposites |
| first_indexed |
2025-11-26T01:42:54Z |
| last_indexed |
2025-11-26T01:42:54Z |
| _version_ |
1850605482394255360 |
| fulltext |
584 Functional materials, 24, 4, 2017
ISSN 1027-5495. Functional Materials, 24, No.4 (2017), p. 584-592
doi:https://doi.org/10.15407/fm24.04.584 © 2017 — STC “Institute for Single Crystals”
Experimental research on mechanical properties
of desert sand steel-PVA fiber engineered
cementitious composites
Che Jialing1, Li Quanwei1, Lee Minggin2, Wang Dan1
1 School of Civil Engineering and Hyd raulic Engineering, Ningxia
University, Yinchuan Ningxia, 750021, P.R.China
2Department of Civil Engineering, Chaoyang University of Technology,
Taichung County, 41349, Taiwan
Received August 23, 2017
An orthogonal experimental design method involving five-factor and four-level is adopted
for the mix design of Desert Sand Steel-PVA fiber ECC. The effect of each level on Mechanical
properties of ECC and the difference of Mechanical properties between each level is analyzed.
The influence of different experimental factors is discussed, which includes water-binder ratio,
fly ash substitution rate, desert sand substitution rate, proportion of PVA fiber and proportion
of steel fiber. The experimental results indicate that water-binder ratio and fly ash substitution
rate are the most principal and significant influencing factors on the compressive strength of
ECC, regardless of age. Steel fiber is conducive to development of splitting tensile strength; PVA
fiber is conducive to the development of flexural strength. High strength ECC can be prepared
when the desert sand substitution rate is high. As the raw material of ECC, river sand can be
90% replaced by desert sand.
Keywords: Desert sand, Engineered cementitious composites(ECC), Mechanical properties,
Orthogonal experiment, PVA fiber, Steel fiber.
Исследуется влияние различных факторов на свойства экологически чистого и
экономически выгодного конструкционного строительного композитного материала (ККМ).
Исследовалась смесь волоконной эмульсии Desert Sand Steel-PVA. Для исследований
использовался метод ортогонального экспериментального проектирования с пятифакторным
(соотношение вода-связующее, скорость замещения летучей золы, скорость замещения песка
пустыни, доли волокна ПВА и доли стального волокна) и четырехуровневым испытанием
на прочность. Экспериментальные результаты показывают, что соотношение воды и
связующего материала, а также скорость замещивания летучей золы являются наиболее
влияющими факторами на прочность на сжатие ККМ, независимо от срока его получения.
Стальное волокно способствует развитию растягивающей силы расщепления; ПВА волокно
способствует развитию прочности на изгиб. Высокопрочный ECC может быть приготовлен,
при большой скорости замещения песка пустынию. В качестве сырья ККМ речной песок
может быть заменен на 90% пустынным песком .
Експериментальні дослідження механічних властивостей конструкційного
композитного матеріалу Desert Sand Steel-PVA. Che Jialing, Li Quanwei, Lee Minggin,
Wang Dan.
Досліджується вплив різних чинників на властивості екологічно чистого та економічно
вигідного конструкційного будівельного композитного матеріалу (ККП). Досліджувалася
суміш волоконної емульсії Desert Sand Steel-PVA. Для досліджень використовувався метод
ортогонального експериментального проектування з п’ятифакторна (співвідношення вода-
Functional materials, 24, 34 2017 585
Che Jialing et al. / Experimental research on mechanical properties ...
1. Introduction
Engineered Cementitious Composites (here-
inafter referred to as ECC) was proposed in the
last late century ECC is micromechanically
designed composites with fiber as reinforce-
ment material, cement as main base material.
It features outstanding energy consuming ca-
pacity, strain hardening and crack steady state
development. ECC can effectively improve the
seismic resistance of the structure [1], extend
service life of the material [2].
Research on steel-PVA cementitious compos-
ites show that addition of fly ash, increase of fiber
proportion help multiple cracking [3.4]. PVA-ECC
has outstanding property of peak delay [5]. The
damage crack of PVA-ECC is less wide, which can
be controlled within 100μm [2, 6], Harbin Insti-
tute of Technology researched high fly ash pro-
portion ECC, its 28d limit tensile strain is all
above 3%, exhibiting outstanding strain-hard-
ening property [7]. From the angle of sustain-
ability of the environment, ECC consumes less
resource, emits less pollution [8]. Adoption of
ECC can increase compressive strength and
tensile strength of the concrete test piece [9].
Experiments show that compressive strength
of 4-day aged ECC can meet the strength re-
quired by deck slab design, conducive to speed-
ing up construction [10]. Using micromechani-
cal design can achieve ideal performance of
ECC [11]. Fly ash, water-binder ratio, fiber dis-
perse condition all can influence tensile proper-
ty of ECC [12, 13]. When steel fiber proportion
is 2.0%, difficult dispersal and serious caking of
steel fiber results strength of ECC lower than
that of the test piece with steel fiber proportion
1,5% [14].
Large amount of non-renewable building
material is consumed, so using a substitute
for building material is of significance for sus-
tainable development of the industry. Sand
for building has limited reserve and cannot
be regenerated within short term worldwide,
while every continent has deserts of different
size, and desert sand can partly substitute for
river sand used for concrete, whose smaller
grain size makes concrete inside more even,
more compact. Currently, the thermal power is
still the main electric source globally, nowhere
can place a large amount of waste fly ash dis-
charged from thermal power plants. Fly ash
can substitute for cement to a certain extent,
and improve performance of concrete, avoid
waste pollution. Desert sand and fly ash are
used in concrete as substitute material, saving
resources and lowering cost. Desert sand steel-
PVA fiber ECC prepared in this paper uses des-
ert sand to substitute for part of river sand, fly
ash to substitute for part of cement.
2. Experiment design
2.1. Experimental material
Saima branded p.o.42.5 ordinary portland
cement of Ningxia, China, its specific surface
area is 339m2/kg, the chemical composition is
shown in Table 1, the properties is shown in
Table 2; for class I fly ash of Ningxia Lingwu
Thermal Power Plant, water content is 0.4%,
water demand ratio is 90%, fineness is 8.4%,
loss on ignition is 3%, the chemical composi-
tion is shown in Table 1; the desert sand is
from Tengger Desert, with average grain size
0.23mm, fineness modulus is 0.7; for sieved
river sand, max grain size is 1.18mm, fineness
modulus is 2.1; PVA fiber is produced by Japan
KURARAY, steel fiber selects copper plated
micro wire steel fiber produced by Hengshui
Fangde Silk Screen Products Factory, per-
formance of fiber is shown in Table 3. Admix-
ture is powdered high efficiency polycarboxylic
acid water reducer, with water reducing rate
25%~30%.
2.2. Proportion of experiment
The paper uses 5-factor 4-level (L1645) or-
thogonal experiment, factors and levels is
shown in Table 4.
Mix design of orthogonal experiment is
shown in Table 5.
2.3. Test piece preparation and experi-
mental method
In order to make PVA fiber and steel fibers
disperse evenly without caking, steel fiber pre-
mixing and PVA fiber after-mixing were adopt-
ed. First mix and agitate river sand and desert
sand for 1min, add cement and fly ash agitat-
ing for 1 min, then add steel fiber agitating for
1min, add water and water reducer agitating for
2min, finally add PVA fiber agitating for 2min.
After agitation cast a test piece and vibrate it
сполучна, швидкість заміщення летючого попелу, швидкість заміщення піску пустелі, частки
волокна ПВА і частки сталевого волокна) і чотирьохрівневим випробуванням на міцність.
Експериментальні результати показують, що співвідношення води і сполучного матеріалу, а
також швидкість замещіванія летючої золи є найбільш впливають факторами на міцність на
стиск ККМ, незалежно від терміну його отримання. Сталеве волокно сприяє розвитку сили,
що розтягує розщеплення; ПВА волокно сприяє розвитку міцності на вигин. Високоміцний
ECC може бути приготований, при великій швидкості заміщення піску пустелі. В якості
сировини ККМ річковий пісок може бути замінений на 90% пустельним піском.
586 Functional materials, 24, 4, 2017
Che Jialing et al. / Experimental research on mechanical properties ...
Table 1. Chemical composition of ordinary portland cement and fly ash
Chemical
composition/% CaO SiO2 Al2O3 Fe2O3 SO3 MgO Na2O K2O Others
Cement 60.24 21.22 5.05 3.26 2.67 0.97 0.73 0.50 5.36
Fly ash 3.16 53.80 24.60 9.32 0.42 1.52 0.28 0.82 6.08
Table 2. Properties of ordinary portland cement
Properties Fineness
/%
Consistency water
consumption /%
initial setting
time /min
Final set-
ting time
/min
Flexural
strength
/MPa
compressive
strength /MPa
Value 4.4 26 130 180 9.0 55.6
Table 3. Performance of experimental fiber
Type Length /mm Color Diameter /mm Tensile
strength/MPa
Modules of
elasticity/GPa
PVA fiber 12 white 0.04 1560 41
Steel fiber 13 yellow 0.2 >2850 210
Table 4. Factors and levels
Factors
Levels
Water-binder
ratio
Fly ash substitute
rate /%
Desert sand
substitute rate/%
Proportion of pva
fiber/%
Proportion of
steel fiber/%
1 0.19 15 0 0 0
2 0.24 30 30 0.4 0.4
3 0.29 45 60 0.8 0.8
4 0.34 60 90 1.2 1.2
Table 5. Mix design of orthogonal experiment
Factors
No.
of specimens
A.
Water-
binder
ratio
B.
Fly ash sub-
stitute rate/%
C.
Desert sand
substitute
rate/%
D.
Proportion of
pva fiber/%
E.
Proportion of
steel fiber/%
1 1 (0.19) 1 (15) 1 (0) 1 (0) 1 (0)
2 1 (0.19) 2 (30) 2 (30) 2 (0.4) 2 (0.4)
3 1 (0.19) 3 (45) 3 (60) 3 (0.8) 3 (0.8)
4 1 (0.19) 4 (60) 4 (90) 4 (1.2) 4 (1.2)
5 2 (0.24) 1 (15) 2 (30) 3 (0.8) 4 (1.2)
6 2 (0.24) 2 (30) 1 (0) 4 (1.2) 3 (0.8)
7 2 (0.24) 3 (45) 4 (90) 1 (0) 2 (0.4)
8 2 (0.24) 4 (60) 3 (60) 2 (0.4) 1 (0)
9 3 (0.29) 1 (15) 3 (60) 4 (1.2) 2 (0.4)
10 3 (0.29) 2 (30) 4 (90) 3 (0.8) 1 (0)
11 3 (0.29) 3 (45) 1 (0) 2 (0.4) 4 (1.2)
12 3 (0.29) 4 (60) 2 (30) 1 (0) 3 (0.8)
13 4 (0.34) 1 (15) 4 (90) 2 (0.4) 3 (0.8)
14 4 (0.34) 2 (30) 3 (60) 1 (0) 4 (1.2)
15 4 (0.34) 3 (45) 2 (30) 4 (1.2) 1 (0)
16 4 (0.34) 4 (60) 1 (0) 3 (0.8) 2 (0.4)
Functional materials, 24, 34 2017 587
Che Jialing et al. / Experimental research on mechanical properties ...
solid. Strip mould after 24h, being cured to 7d,
28d. After curing, dry the test piece and con-
duct mechanical property experiment.
Measure failure load on universal testing ma-
chine, calculating compressive strength, split-
ting tensile strength, flexural strength accord-
ing to corresponding equation respectively.
The compressive strength was measured by
the 70.7mm ´ 70.7mm ´ 70.7mm cube speci-
mens, the tensile strength was measured by
the 100mm ´ 100mm ´ 100mm cube speci-
mens, and the flexural strength was measured
by 40mm ´ 40mm ´ 160mm prism specimens.
3. Experimental result and analysis
Experimental results of 7d, 28d compres-
sive strength and splitting tensile strength and
28d flexural strength are shown in Table 6. The
purpose of this experiment is to study the effect
of individual factors on the properties of ECC,
and the combination of the interaction between
the factors is complex, so the interaction be-
tween factors is not discussed in this paper.
3.1. Intuitive analysis
It is known from No. 3 and No.7 28d com-
pressive strength in Table 6 that:
When water-binder ratio is the lowest (0.19),
fly ash substitution rate is 45%, when using
high desert sand substitute (60%), we can still
prepare high strength ECC with compressive
strength above 75Mpa (No. 3); when water-
binder ratio is low (0.24), even fly ash substi-
tution rate is up to 45%, using extremely high
desert sand substitution rate (90%), the com-
pressive strength is still up to 60 Mpa (No. 7).
3.2. Range analysis
Range analysis is shown in Table 7.
The influence trends of each factor in the
strength is shown in Figure 1.
It is known from Table 7 and Figure 1 that:
(1) As water-binder ratio increases, com-
pressive strength, splitting tensile strength
and flexural strength show decreasing trend;
increase of the fly ash substitution rate will
result in a decrease of 3 properties. As desert
sand substitution rate increases, compressive
strength and splitting tensile strength both
increase first and decrease slowly then. Flex-
ural strength shows the trend of slow decrease.
When the desert sand substitution rate is 30%,
compressive strength and splitting tensile
strength reach the highest; as Proportion of
PVA fiber increases, compressive strength and
splitting tensile strength increases first and de-
creases then, when the proportion is 0.8%, com-
pressive strength and splitting tensile strength
reach the highest; flexural strength increases
with progressive increase of proportion of PVA
fiber. As a proportion of steel fiber increases,
compressive strength increases first and de-
Table 6. Experimental results
Properties
No. of
specimens
7d compressive
strength/MPa
7d split-
ting tensile
strength/MPa
28d compres-
sive strength/
MPa
28d split-
ting tensile
strength/MPa
28d flexural
strength/MPa
1 59.47 12.33 81.58 15.61 13.19
2 69.89 26.71 94.07 23.45 14.27
3 56.21 21.49 75.08 29.84 20.86
4 33.42 25.69 52.87 24.46 17.25
5 75.04 32.14 87.43 37.67 24.54
6 56.58 19.24 71.85 20.25 22.9
7 46.06 15.18 60.67 18.01 7.60
8 41.73 12.11 47.55 8.58 5.24
9 51.79 18.29 61.16 20.92 15.66
10 42.41 13.15 55.26 14.86 10.16
11 40.11 14.76 56.07 27.73 15.47
12 23.82 8.21 36.17 14.03 5.99
13 44.45 14.70 55.08 16.81 9.48
14 34.46 13.77 53.92 20.97 11.15
15 28.55 9.81 39.88 13.65 13.83
16 23.38 7.95 36.18 11.75 10.02
588 Functional materials, 24, 4, 2017
Che Jialing et al. / Experimental research on mechanical properties ...
creases then, splitting tensile strength and
flexural strength show an increasing trend.
(2) For 7d compressive strength, ranking of
every influencing factors is: fly ash substitution
rate (B)> water-binder ratio (A)> Proportion
of PVA fiber(D) > desert sand substitute (C) >
Proportion of steel fiber(E), the better combina-
tion of condition is A2B1C2D3E2. For 28d com-
pressive strength, ranking of every influencing
factors is: water-binder ratio (A) > fly ash sub-
stitution rate (B) >desert sand substitute (C) >
Proportion of PVA fiber(D) >Proportion of steel
fiber(E), the better combination of condition is
A1B1C2D3E2. For 7d splitting tensile strength,
ranking of every influencing factors is: water-
binder ratio (A) >Proportion of steel fiber(E) >
Proportion of PVA fiber(D) > fly ash substitution
rate (B) >desert sand substitute (C), the bet-
ter combination of condition is A1B1C2D3E4.
For 28d splitting tensile strength, ranking of
every influencing factors is: Proportion of steel
fiber(E) >fly ash substitution rate (B) >water-
binder ratio (A)>Proportion of PVA fiber(D)
>desert sand substitute (C), the better combi-
nation of condition is A1B1C2D3E4. For 28d
flexural strength, ranking of every influencing
factors is: Proportion of PVA fiber(D) > Propor-
tion of steel fiber(E) >fly ash substitution rate
(B)>water-binder ratio (A) >desert sand substi-
tute (C), the better combination of condition is
A1B1C1D4E4.
(3) The influence of water-binder ratio
and fly ash substitution rate of compressive
strength is especially significant; 7d splitting
tensile strength is influenced by water-binder
ratio most; 28d splitting tensile strength is
influenced by Proportion of steel fiber most;
Figure 1. Influence trends of each factor in the
strength: (a) 7d compressive strength; (b) 7d
splitting tensile strength; (c) 28d compressive
strength; (d) 28d splitting tensile strength; (e)
28d flexural strength.
Functional materials, 24, 34 2017 589
Che Jialing et al. / Experimental research on mechanical properties ...
Proportion of PVA fiber influences flexural
strength most.
(4) According to integrated balance method,
better combination of conditions is determined
as A1B1C2D3E4.
3.3. Variance analysis
Variance analysis is shown in Table 8. Tak-
ing into account the four-level and five-factor
orthogonal test, in the variance analysis, the
factor whose mean square is the smallest is
considered as error to calculate the value of F.
It is known from Table 8 that:
–According to mean square value, rank sig-
nificance of influence of every factor on mechan-
ical property from large to small, for splitting
tensile strength, flexural strength, 7d compres-
sive strength, the ranking is in accordance with
range analysis; for 28d compressive strength,
ranking of influence of every factors is: water-
binder ratio (A) >fly ash substitution rate (B)
>Proportion of PVA fiber(D) >desert sand sub-
stitute (C) >Proportion of steel fiber(E), slightly
different from range analysis.
– Water-binder ratio (A) and fly ash substitu-
tion rate (B) influence 7d compressive strength
highly significantly (α = 0.01), influence 28d
compressive strength moderately significant (α
= 0.05); Proportion of steel fiber(E) influences
28d splitting tensile strength significantly.
Variation of desert sand substitute (C) does not
influence every performance obviously.
4. Failure modes of specimens
4.1. Compression failure
The specimen without fiber often breaks
unexpectedly, with the larger piece falling off
as shown in Figure 2 (a). The specimen with
only steel fiber has small piece falling off, with
relatively complete contour, the surface shows
several cracks with certain width, as shown in
Table 7. Range analysis
Factors
Properties
A.
Water-binder
ratio
B.
Fly ash substi-
tution rate/%
C.
Desert sand
substitution
rate/%
D.
Proportion of
pva fiber/%
E.
Proportion of
steel fiber/%
7d compressive
strength
K1 54.75 57.69 44.89 40.95 43.04
K2 54.85 50.84 49.33 49.05 47.78
K3 39.53 42.73 46.05 49.26 45.27
K4 32.71 30.59 41.59 42.59 45.76
R 22.14 27.10 7.74 8.31 4.74
7d splitting ten-
sile strength
K1 21.56 19.37 13.57 12.37 11.85
K2 19.67 18.22 19.22 17.07 17.03
K3 13.60 15.31 16.42 18.68 15.91
K4 11.56 13.49 17.18 18.26 21.59
R 10.00 5.88 5.65 6.31 9.74
28d compres-
sive strength
K1 75.90 71.31 61.42 58.09 56.07
K2 66.88 68.78 64.39 63.19 63.02
K3 52.17 57.93 59.43 63.49 59.55
K4 46.27 43.19 55.97 56.44 62.57
R 29.63 28.12 8.42 7.05 6.95
28d splitting
tensile strength
K1 23.34 22.75 18.84 17.16 13.18
K2 21.13 19.88 22.20 19.14 18.53
K3 19.39 22.31 20.08 23.53 20.23
K4 15.80 14.71 18.54 19.82 27.71
R 7.54 8.04 3.66 6.37 14.53
28d flexural
strength
K1 16.39 15.72 15.40 9.48 10.61
K2 15.07 14.62 14.66 11.12 11.89
K3 11.82 14.44 13.23 16.40 14.81
K4 11.12 9.63 11.12 17.41 17.10
R 5.27 6.09 4.28 7.93 6.49
590 Functional materials, 24, 4, 2017
Che Jialing et al. / Experimental research on mechanical properties ...
Figure 2(b). The specimen with steel-PVA fiber
has many micro cracks in the surface, with al-
most nothing falling off in the surface, keeping
good integrity, as shown in Figure 2(c), with
cracks marked with marker pen.
4.2 Splitting failure
The specimen without fiber will suddenly
split with a “Bang” under max load, totally
breaking, as shown in Figure 3(a). The speci-
men with only steel fiber will form several
wider main cracks, and the specimen is still
linked together, as shown in Figure 3(b). The
specimen with steel-PVA fiber forms 1 or two
thinner main cracks and several micro cracks,
failure mark in the surface is not apparent, as
shown in Figure 3(c).
Table 8. Variance analysis
Properties Variance
origin Square Sum degree of
freedom
Mean
square F Critical value
7d com-
pressive
strength
A SA=1488.698 3 496.233 32.746*** F0.01 (3, 3) =29.5
B SB=1628.132 3 542.711 35.814*** F0.05 (3, 3) =9.3
C SC=122.519 3 40.840 2.695 F0.1 (3, 3) =5.4
D SD=223.502 3 74.501 4.916 —
E SE= 45.461 3 15.154 1.000 —
Error Se= 45.461 3 15.154 — —
Total ST=3508.311 15 — — —
7d split-
ting tensile
strength
A SA=273.493 3 91.164 4.168 F0.01 (3, 3) =29.5
B SB=86.391 3 28.797 1.317 F0.05 (3, 3) =9.3
C SC=65.611 3 21.870 1.000 F0.1 (3, 3) =5.4
D SD=100.707 3 33.569 1.535 —
E SE= 192.503 3 64.168 2.934 —
Error Se= 65.611 3 21.870 — —
Total ST=718.704 15 — — —
28d com-
pressive
strength
A SA=2199.000 3 733.000 17.707** F0.01 (3, 3) =29.5
B SB=1965.632 3 655.211 15.828** F0.05 (3, 3) =9.3
C SC=149.889 3 49.963 1.207 F0.1 (3, 3) =5.4
D SD=153.330 3 51.110 1.235 —
E SE= 124.187 3 41.396 1.000 —
Error Se= 124.187 3 41.396 — —
Total ST=4592.038 15 — — —
28d split-
ting tensile
strength
A SA=121.824 3 40.608 3.661 F0.01 (3, 3) =29.5
B SB=163.682 3 54.561 4.919 F0.05 (3, 3) =9.3
C SC=33.274 3 11.091 1.000 F0.1 (3, 3) =5.4
D SD=85.166 3 28.389 2.560 —
E SE= 432.651 3 144.217 13.003** —
Error Se= 33.274 3 11.091 — —
Total ST=836.597 15 — — —
28d flexural
strength
A SA=77.111 3 25.704 1.816 F0.01 (3, 3) =29.5
B SB=88.122 3 29.374 2.075 F0.05 (3, 3) =9.3
C SC=42.468 3 14.156 1.000 F0.1 (3, 3) =5.4
D SD=181.829 3 60.610 4.282 —
E SE= 102.513 3 34.171 2.414 —
Error Se= 42.468 3 14.156 — —
Total ST=492.043 15 — — —
NOTE: *** Significant at α level of 0.01;** Significant at α level of 0.05.
Functional materials, 24, 34 2017 591
Che Jialing et al. / Experimental research on mechanical properties ...
4.3 Flexural failure
The specimen without fiber gives out crisp
sound of breaking when failing, the test piece
is bent to two halves totally, as shown in Fig-
ure 4(a). The test specimen with only steel fiber
forms a wider crack in tensile area, the com-
pressive area is still linked together, as shown
in Figure 4(b). The specimen with steel-PVA
fiber breaks to smaller cracks in compressive
area, with relatively integrated form, as shown
in Figure 4(c).
4.4 Cause analysis
Test pieces with different type of fiber have
different failure modes(There is no significant
difference between specimens with only PVA fi-
ber and specimens with steel-PVA fiber, so the
failure mode of a specimen with only PVA fiber
is not presented in the text). Two kinds of fiber
used in the experiment are different greatly
in size of the diameter, playing bridging role
in different scale. PVA fibers mainly controls
micro crack at an early stage of bearing load,
steel fiber mainly controls macro crack. The
test piece without fiber will generate a fragile
burst failure; steel fiber ECC typically produces
several wider main cracks when it fails; steel-
PVA fiber ECC will produce many micro cracks
when it fails, the form is damaged less, failure
is slow, showing better ductility.
5. Conclusion
Using inexhaustible desert sand and indus-
trial waste fly ash, through orthogonal experi-
ment, this paper mainly researches influence
trend of 5 factors, including water-binder ratio,
fly ash substitution rate, desert sand substitu-
tion rate, proportion of PVA fiber, and propor-
tion of steel fiber on ECC strengths, in order
to find main factor influencing strength. Ac-
cording to failure mode of test pieces, the role
Figure 2. Compression failure modes. (a) Specimen without fiber (b) Specimen with only steel fiber (c)
Specimen with steel-PVA fiber.
Fig. 3. Splitting failure modes. (a) Specimen without fiber, (b) Specimen with only steel fiber, (c) Specimen
with steel-PVA fiber.
Fig. 4. Flexural failure modes. (a) Specimen without fiber, (b) Specimen with only steel fiber, (c) Specimen
with steel-PVA fiber.
592 Functional materials, 24, 4, 2017
Che Jialing et al. / Experimental research on mechanical properties ...
played in desert sand ECC by different fiber is
analyzed. And it is concluded that:
– When water-binder ratio is low, even if
adopting high fly ash substitute and adding
large amount of desert sand, high strength ECC
can still be prepared, which is of significance
for desert sand ECC at key location of high rise
anti-seismic structure.
– According to integrated balance method,
finalized better condition of factor combination
is A1B1C2D3E4, namely water-binder ratio is
0.19, fly ash substitution rate is 15%, the des-
ert sand substitution rate is 30%, proportion of
PVA fiber is 0.8%, proportion of steel fiber is
1.2%.
–Water-binder ratio and fly ash substitu-
tion rate influence compressive strength highly
significant (a = 0.01), but low water-binder ra-
tio and fly ash substitution rate result in even
larger compressive strength; proportion of
steel fibers significantly (a = 0.05) influences
28d splitting tensile strength, and steel fiber
is conducive to development of splitting tensile
strength; PVA fiber is conducive to the develop-
ment of flexural strength.
– Desert sand substitution rate does not sig-
nificantly influence every mechanical proper-
ties, but appropriate desert sand substitution
rate can improve ECC property to a certain de-
gree. In addition, max desert sand substitute
in the experiment has been up to 90%, and the
experimental group adopting 90% desert sand
substitution rate does not decrease obviously in
compressive strength, splitting tensile strength
compared with the experimental group without
desert sand, but flexural strength decreases to
some extent. So it is inferred that as raw ma-
terial of ECC, desert sand can further totally
substitute for river sand.
– PVA fiber enhances ductility of desert
sand ECC, making the failure process of test
piece failure intend to slow, conducive to multi-
crack development of failure.
Acknowledgements
This work was financially supported by the
National Natural Science Foundation of China
with No. 51408328.
References
1. V. C. Li, D.K. Mishra. A.E. Naaman, et al, Adv.
Cement Based Mater., 1, 142, 1994.
2. V. C. Li, J. Adv. Conc. Techn., 1, 215,2003.
3. S. F. U. Ahmed, M. Maalej, P. Paramasivam, J.
Ferrocement, 33, 172, 2003.
4. S. F. U. Ahmed, M. Maalej, P. Paramasivam,
Constr. Building Mater., 21, 1088, 2007.
5. G. Fischer, V. C. Li, Struct. J., 99, 781, 2002
6. Xu Shilang, Cai Xinhua, Acta Mater. Compos.
Sinica, 27, 177, 2010.
7. Y. Zhu, Y. Yang, Y. Yao, Constr. Building Ma-
ter., 36, 1076, 2012.
8. H. Zhang, M.D. Lepech, G.A. Keoleian, et al, J.
Infrastruct. Syst., 16, 299, 2009.
9. M. Şahmaran, V. C. Li, Structures Congress
2009: Don’t Mess with Structural Engineers:
Expanding Our Role., 1-13, 2009.
10. M.D. Lepech, V. C. Li, Mater. Struct., 42, 1185,
2009.
11. V. C. Li, Int. J.Concrete Struct.Mater., 6, 135,
2012.
12. K. Sirijaroonchai, S. El-Tawil, G. Parra-Mon-
tesinos, Cement Concrete Comp, 32, 62, 2010.
13. M. Li, V.C. Li, Mater. Struct., 46, 405, 2013.
14. Z. Zhang, S. Qian, H. Ma, Constr.Building Ma-
ter., 52, 17, 2014.
|