Structural Performance of One-Way Slabs Reinforced with Steel and Polypropylene Fibers

Abstract

The present study aims to investigate the effects of the steel fibers (SF) and polypropylene fibers (PPF) on the structural response of one-way simply supported reinforced concrete (RC) slabs at the ultimate limit state (ULS). Next, an optimized combination of the hybrid fibers is proposed. The experimental program includes 21 experiments on the one-way slabs with different SF and PPF ratios. The load-deflection curves were obtained for slabs using a four-point bending method. The ultimate capacity and mid-span deflection of the slabs were measured. The experimental results did not produce a consistent trend of ultimate loading. The different blends produced different failure modes, cracking load, and ultimate failure load. Based on the obtained test results, the slab specimen, SM6, with 0.7% SF and 0.9% PPF ratios has the maximum and the slab specimen, SM16, with 0.9% SF and 0.9% PPF ratios has the minimum load-carrying capacity, respectively. The first shows a 31% increase and the second indicates a 31% reduction when compared to the reference slab specimen, SM1, which has no fibers used in its concrete mixture. It is worth to mention that the slab specimen, SM6, which has the largest load-carrying capacity, also shows the highest ductility (172% enlargement in deflection when compared to the reference slab, SM1).

Full text

Jurnal Kejuruteraan 33(2) 2021: 193-203
https://doi.org/10.17576/jkukm-2021-33(2)-04
Structural Performance of One-Way Slabs Reinforced with Steel and
Polypropylene Fibers
Qaiser uz Zaman Khana; Afaq Ahmada*, Ali Razab, Mojtaba Labibzadehc & Muhammad Iqbald
aDepartment of Civil Engineering, University of Engineering and Technology, Taxila, 47080, Pakistan
bDepartment of Civil Engineering, Pakistan Institute of Engineering and Technology, Multan, 66000, Pakistan
cDepartment of Civil Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
dCreative Engineering & Management Solutions, Deans Centre Peshawar, 25000, Pakistan
*Corresponding author: afaq.ahmad@uettaxila.edu.pk
Received 01 July 2020, Received in revised form 20 August 2020
Accepted 15 September 2020, Available online 30 May 2021
ABSTRACT
The present study aims to investigate the effects of the steel fibers (SF) and polypropylene fibers (PPF) on the structural
response of one-way simply supported reinforced concrete (RC) slabs at the ultimate limit state (ULS). Next, an optimized
combination of the hybrid fibers is proposed. The experimental program includes 21 experiments on the one-way slabs
with different SF and PPF ratios. The load-deflection curves were obtained for slabs using a four-point bending method.
The ultimate capacity and mid-span deflection of the slabs were measured. The experimental results did not produce a
consistent trend of ultimate loading. The different blends produced different failure modes, cracking load, and ultimate
failure load. Based on the obtained test results, the slab specimen, SM6, with 0.7% SF and 0.9% PPF ratios has the
maximum and the slab specimen, SM16, with 0.9% SF and 0.9% PPF ratios has the minimum load-carrying capacity,
respectively. The first shows a 31% increase and the second indicates a 31% reduction when compared to the
reference slab specimen, SM1, which has no fibers used in its concrete mixture. It is worth to mention that the slab
specimen, SM6, which has the largest load-carrying capacity, also shows the highest ductility (172% enlargement in
deflection when compared to the reference slab, SM1).
Keywords: Hybrid Fiber-reinforced concrete slabs; Flexural testing; One-way slabs; Polypropylene fibers; Load-
carrying capacity; Ductility
INTRODUCTION
The reinforced concrete (RC) material is the most widely
used material in the construction industry due to its readily
and low-cost preparation procedure, its ability to be adapted
in the required shapes and its already established properties
such as high strength, high durability, re-resistance, and
so on. It has replaced stone and brick masonry as a building
material. At present, reinforced concrete is used in all the
types of construction starting from a simple house to a
multi-story building. One-way reinforced concrete slabs are
one of the frequently used RC members usually utilized in
the buildings as the oor system or bridges as the decks. The
enhancement of the strength and durability of the RC slabs
is always an active area in the research works. Concrete is
categorized as a brittle material and has low tensile strength,
especially after the appearance of cracks, the load-carrying
mechanism is highly compromised. The shrinkage cracks
have always been a noticeable problem in the concrete
structures. These cracks can be easily observed in concrete
pavement slabs and the slabs under high-speed railways.
For such structural elements, there is always a problem
for the control of cracks that appear due to the expansion
and contraction of concrete due to temperature changes.
The bers escalate toughness and ability to resist crack in
hardened concrete by transferring the load at internal micro-
cracks (Abbas et al. 2012; Shende et al. 2012). However,
Therefore, with the advancement in composite material,
especially bers, the strength and durability of concrete can
be enhanced by using dierent types of bers (Mohammadi
et al. 2008; Abdul-Zaher et al. 2016; Raza and Khan 2020).
Fiber-reinforced concrete (FRC) matrix primarily
consists of hydraulic cement with ne and coarse aggregates
and string-like discrete bers. The toughness and the
resistance to impact loadings are increased by using the
synthetic and organic bers having low elastic modulus
and high elongation properties while the strength and the
stiness characteristics of concrete are improved using
steel and carbon bers having high elastic modulus (Singh
2010). An experimental and numerical study of HFRC
(hybrid ber-reinforced concrete) shows that a combination
of PVA, PPF, and carbon bers with a volumetric ratio of
0.4% decreased the cracking and shrinkage of concrete up to
34% (Denneman et al. 2011). Moreover, due to the addition
of bers, there is no inuence on the loss of water from
concrete by evaporation (Wongtanakitcharoen et al. 2007).
PPF-reinforced concrete has a higher tendency of cracking
due to higher elastic modulus and higher shrinkage (Aly et

194
al. 2008). The bers that are extensively used in concrete,
are steel ber, SF, and PPF (Bažant and Kazemi 1990; Shah
et al. 1995). The mechanical properties of PPF reinforced
concrete at elevated temperatures and high loads were
inuenced by the cross-sectional area of PPF (Di Prisco
et al. 2009; Kim et al. 2013). Moreover, the spalling and
brittle failure of concrete was increased due to the elevated
temperatures and external loadings. To control the plastic
and dry shrinkage cracking, a volumetric proportion of
0.1% of the polypropylene and glass bers is enough
(Banthia and Gupta 2006; Barluenga and Hernández-
Olivares 2007).
The overall eciency of bers depends upon the
ber-matrix interactions (Abbas and Khan 2016). The
PPF reinforced concrete helps in reducing the thickness of
members and hence, reducing the weight of the structure,
which makes handling, and shipping of the concrete, even
easier (Singh 2010). Wu et al. (Wu et al. 2019) investigated the
eect of SF on the exural behavior of glass ber reinforced
polymer (GFRP) reinforced beams and concluded that by the
addition of 0.6% SF by volume, the load-carrying capacity
increased by 22%. The use of ordinary concrete where the
compaction is done using a mechanical vibrator, the most
reliable and widely used method is the use of bers to reduce
cracks, which are caused by paste contracts particularly thin
articial bers with a volume less than 0.5% (Brandt and
Gupta 2006). The tests on the ber-reinforced concrete have
shown that the compressive, tensile, and bending strengths
increase, and the workability decreases with the higher
volume of bers (Brandt et al. 2003; ZHANG and LI 2008,
Wang and Chouw 2018, Ahmad, Tahir et al. 2019). The
surface cracks formed due to the internal vapor pressure of
concrete may cause the spalling of concrete or the corrosion
of reinforcement by reducing the performance of structure
(Han et al. 2005; Naaman et al. 2005; Song et al. 2005;
Sivakumar and Santhanam 2007; Pelisser et al. 2010). The
compressive strength of the concrete is slightly aected
by the increase in the quantity of PPF and glass bers
(Sivakumar and Santhanam 2007; Hsie et al. 2008; Sun and
Xu 2009). The addition of PPF reduces the expansion of
concrete and increases the strength signicantly which helps
the structure to stay in the more serviceable state (Qian and
Stroeven 2000; Kakooei et al. 2012). With the increase of
bers quantity, the tensile strength of concrete can also be
increased (Selina et al. 2014). The use of PPF by 0.1% is
very less ecient for the on-grade slab whereas the use
of 0.5% of PPF produced much more resistance to impact
loading (Manolis et al. 1997). Fibers play an important role
in resisting the exural cracks in slabs (Pujadas et al. 2012;
di Prisco et al. 2019; Facconi et al. 2019; AbdelmajeedLabib
2020; Kueres et al. 2020).
The present work aims to investigate the eect of
dierent combinations of the SF and PPF (hybrid bers) on
the overall structural response of the one-way RC slabs. To
achieve this purpose, 21 one-way RC slab specimens were
cast and tested under a four-point exural test to assess their
load-carrying capacity, deection, and cracking patterns at
the ultimate limit state (ULS). This study could be helpful
for the structural engineers in the analysis and design of
such members under ULS.
EXPERIMENTAL SCHEME AND SETUP
EXPERIMENTAL PROGRAM
21 tests were carried out to study experimentally the behavior
of the HFRC slab at ULS. Each of the slab specimens is
named with numeric digit prexed with alphabet SM where
S denotes the specimen of one-way slab and M denotes the
mix design. There are 21 dierent mix designs in the present
experimental program. The ratio of SF and PPF varies
between 0 to 1.0% and 0 to 0.9%, respectively. A summary
of the tests which are conducted is provided in Table 1.
MATERIALS
In this research program, Type II Grade 43 Ordinary
Portland Cement (OPC) was used fullling the requirements
of ASTM C150/150M-18 (2018). The physical properties
and chemical composition of the cement are given in Table
2. The coarse aggregates used in this research program are
Margallah crush having a neness modulus of 2.3 and the
source of ne aggregates was Lawrencepur sand following
ASTM C33/C33M-18 (2018). The maximum size of
coarse aggregates was 12 mm. The mechanical properties
of steel and PPF (see Figure 1) are shown in Table 3. The
superplasticizer Chemrite NN was used by the weight of the
cement, having a pH value of 8.0 to enhance the workability
of concrete. The specications of the superplasticizer are
given in Table 4.
PREPARATION OF SPECIMENS
Twenty-one samples of one-way RC slabs with dimensions
of 1016 mm x 457 mm x 100 mm were cast. The SF and
PPF bers ratio for each mixture varies from 0% to 1.0%
and 0% to 0.9%, respectively. The mix ratio of 1:1.4:2.8 was
developed. Water to cement ratio of 0.47 was used for the
mixture. Table 5 shows the mixed proportion of concrete.
There were used three longitudinal and seven transverse
steel bars of 10 mm diameter having a yield strength of 410
MPa at equal spacing on the top and bottom of the slabs.
The concrete cover on the sides of slabs was 20 mm and that
was 15 mm at the top and bottom of the slabs. Before the
casting of specimens, the slump value for each mix design
was determined. It was observed that the slump value of
HFRC decreases with the increase of bers being used in
concrete. It is well known that the addition of bers to the
concrete matrix generally tends to increase the porosity
and, at the same time, to reduce the workability of fresh
paste. A decrease of 188% occurred in the slump value of
concrete when the SF increased from 0% to 1.0% and PPF
increased from 0% to 0.9%. The larger contents of SF and
PPF will lead to the balling and a thicker mix by reducing

195
FIGURE 1. Polypropylene and steel Fibers
TABLE 1. Test Matrix of the present research work
Sr. No. Slab label SF (%) PPF (%) Total percentage of bers (%)
1 SM1 0.0 0.0 0.0
2 SM2 0.7 0.1 0.8
3 SM3 0.7 0.3 1.0
4 SM4 0.7 0.5 1.2
5 SM5 0.7 0.7 1.4
6 SM6 0.7 0.9 1.6
7 SM7 0.8 0.1 0.9
8 SM8 0.8 0.3 1.1
9 SM9 0.8 0.5 1.3
10 SM10 0.8 0.7 1.5
11 SM11 0.8 0.9 1.7
12 SM12 0.9 0.1 1.0
13 SM13 0.9 0.3 1.2
14 SM14 0.9 0.5 1.4
15 SM15 0.9 0.7 1.6
16 SM16 0.9 0.9 1.8
17 SM17 1.0 0.1 1.1
18 SM18 1.0 0.3 1.3
19 SM19 1.0 0.5 1.5
20 SM20 1.0 0.7 1.7
21 SM21 1.0 0.9 1.9
TABLE 2. Properties of cement
Property Consistency Initial Setting
Time
Final Setting
Time Soundness Fineness Specic
Gravity
Compressive Strength
(28 Days)
Value 28.75% 91 min 3 Hours & 45
min
No
Expansion 3190 cm2/g 3.03 41.13 MPa
TABLE 3. Mechanical properties of steel and PPF
Property Steel Fiber Polypropylene Fibers
Density N/A 0.9 ± 0.01 Kg/L
Diameter 0.55 mm 22 μm
Type Hooked end N/A
Length 35 mm Variable
Tensile Strength 1345 MPa 300-450 MPa
Aspect Ratio 64 N/A
Melting Point 2300oC 1600oC

196
the workability. Three cylinders were also cast for each of
the mixtures. The compressive and tensile strengths of the
latter specimens were assessed on the same day as the slabs
were tested. The compressive strength of all the specimens
were obtained using a universal testing machine (UTM)
with a maximum capacity of 2000 kN following ASTM C39
/ C39M-18 . The complete stress-strain curves for all mix
designs were presented in Figure 2.
EXPERIMENTAL TESTING AND PROCEDURE
The specimens were subjected to the four-point exural
test. The testing procedure was adopted from (Adom-
Asamoah and Kankam 2009). The testing setup contained
slab specimens xed in a steel frame with simply supported
end conditions. The four-point loading mechanism was
adopted as demonstrated in Figure 3. A length of 50 mm
of the slabs from both ends was placed on the supports.
The distance between the supports was 305 mm. The
load was applied using two steel bars placed at one-thirds
points of the slab with the help of a load cell having a
loading capacity of 2000 kN. Three LVDTs were placed at
the bottom of the slab to measure the vertical deections
on 1/3rd, 2/3rd, and mid-point of the slab. All the strain
gauges were attached to the same tension side of the slab
to measure the maximum strain on that tension side. The
load was applied to the slabs with an interval of 5 kN
using the load cell. The load-deection curves for all the
specimens were measured using a data logger connected
to the load cell. Moreover, the initial crack loads, vertical
deections at the initial crack, ultimate loading capacity,
and corresponding vertical deections were measured for
all HFRC slab specimens by hand when cracks appeared
on the surface of the specimens.
RESULTS AND DISCUSSIONS
FIRST CRACK LOAD AND DEFLECTION BEHAVIOR
For specimens SM21 with the maximum amount of SF and
PPF, the rst crack appeared at a nominal loading of just
56.65 kN which is much lesser than the load attained by
control specimen. This is due to the reason that the increased
amount of bers causes the capacity of slabs to be decreased.
The concrete material becomes brittle at larger amounts of
bers. On the other hand, in the case of SM3 where only
0.7% of SF and only 0.3% of polypropylene was used,
yielded a much better result of carrying a load of 91.13 kN.
All the experimental results are presented in Table 6. When
using polypropylene, there was a signicant increase in the
maximum deection obtained by specimens as compared
to the control specimen (SM2). The maximum amount of
deection was reaching the limit of 18.9 mm for 0.7% SF
and 0.9% PPF. This was achieved in the specimen named
SM6. According to experimental results, it was observed
that with the use of more polypropylene, the more elastic
behavior of concrete was obtained. It can be observed that
while using 0.7% SF, the rst crack deection and the
deection at ultimate crack loading are increased with the
increase of PPF. Similarly, when the PPF along with 0.8%
SF, were increased from 0.1% to 0.9% with an increment
of 0.2%, the eect of increasing the SF on the rst crack
deection was irregular but on the deection at ultimate
loading was in the form of an increasing trend i.e., there
was an increase of load-carrying capacity from 83.69 kN
to 99.37 kN. It was noted that the eect of PPF along with
the combination of 0.9% SF, on the rst crack deection
and deection at ultimate crack loading was rst decreasing
and then increasing with the use of 0.9% PPF. By increasing
the PPF up to 0.7%, the rst crack load and deection at
rst crack loads were decreased from 81.45 kN to 36.65 kN
and 5.35 mm to 3.14 mm, respectively. Moreover, when
the combinations of 1.0% SF with dierent increasing
quantities of PPF were used, the loading at rst crack and the
deection at rst crack loads were rst increased from 56.81
kN to 90.25 kN and 3.75 mm to 7.1 mm, respectively, using
PPF up to 0.5% PPF quantity and then started to decrease up
to 64.8 kN and 4.4 mm, respectively, while using 0.9% PPF.
RESULTS AT ULTIMATE LOADING
After the formation of the rst cracks, the load-bearing
capacity of specimens decreased for plain concrete
(SM1). The experimental load carrying capacities and the
corresponding deections at rst cracks and the ultimate
crushing of the slab specimens were shown in Figure 4 and
Figure 5. We can observe that while using 0.7% SF, the
ultimate crack loading and deection are increased with
the increase of PPF by 28.25% and 101.89%, respectively.
Similarly, when the PPF along with 0.8% SF, were increased
from 0.1% to 0.9% with an increment of 0.2%, the eect of
increasing the PPF on the rst crack loading was irregular
but on the ultimate loading capacity was in the form of an
increasing trend from 83.69 kN to 99.37 kN. The eect of
TABLE 4. Specication of superplasticizer
S. No. Description Details
1. The density of at 25°C Approximately 1.18 Kg/ltr
2. PH value Approximately 8
3. The chloride content of NN Nil (EN 934-2)
4. Toxicity Non-toxic
5. Transportation Non-hazardous

197
PPF along with the combination of 0.9% SF, their eect
on the rst and ultimate crack loading was inverse; by
increasing the PPF, the ultimate crack loads and deection
were decreased by 46.86% and 38%, respectively. Moreover,
when the combinations of 1.0% SF with dierent increasing
quantities of PPF were used, the ultimate crack loads and
deection were rst increased up to 28.17% and 37.66%,
respectively using 0.5% PPF quantity and then started to
decrease by 26.36% and 7.79%, respectively. It can be
concluded that that the eect of PPF on the loading capacity
of slabs was similar to that of on vertical deections.
The experimental results did not produce a consistent
trend of ultimate loading. The dierent blend produced
dierent failure modes, cracking load, and ultimate failure
load. The sample SM1 which has lesser initial crack loading
than the control element took almost the same amount of
loading to fail as compared to the control specimen. SM5
had the rst crack at lesser loading than SM4 and SM6
and, also took less load for the specimen to completely fail.
The maximum loading was attained by SM6 (see Figure 6)
which had 0.7 % of SF and 0.3% of PPF and the maximum
ductility was observed for the specimen SM6 having the
SF of 0.7% and PPF of 0.9%. Figure 6 presents the load-
deection behavior of slabs with 0.7% SF and 0.9% PPF
with the maximum capacity and deection of 117.29 kN and
18.90 mm, respectively, for the specimen SM6. Figures 6,
7, 8, and 9 presents the experimentally obtained loads and
corresponding deections curves for the slab specimens.
The high percentage of bers presented low load carrying
capacity of slabs. This may be ascribed to the addition of
large quantity of steel bres that may lead to congestion of
bres resulting in an improper bonding with concrete and
the balling eect.
CRACK PATTERNS
The crack patterns of all slab specimens were examined
as presented in Figure 10. The samples SM1, SM3, SM4,
SM8, SM12, SM18, SM19, and SM20 failed in exure
representing that the specimens were included the quantities
of bers that resist the specimen against shear failures.
While the specimens SM2, SM5, SM6, SM7, SM9, SM13,
SM14, SM15, SM16, and SM21 failed in shear. These
specimens consist of increased quantities of bers causing
the failure of specimens at the supports. The specimens
SM10, SM11, and SM17 failed in shear failure with various
exure cracks. These were mostly the shear cracks showing
that the PPF of higher percentage quantities (0.7-0.9%)
cause the one-way slabs specimens to fail under combined
shear and exural cracks. Due to the bridging eect of the
ber matrix, the cracked concrete cover remained in contact
with the specimens instead of spalling.
TABLE 5. Quantities of concrete constituents
Material Density (Kg/m3)
Cement 468.26
Coarse aggregates 1310.86
Fine aggregates 655.43
Superplasticizer 0.5% by volume
Water 220.08
Steel ber 0-1.0% by volume
Polypropylene ber 0-0.9% by volume
Water to cement ratio 0.47
FIGURE 2. The compressive stress-strain curves of HFRC mix ratios

198
FIGURE 3. Testing setup for HFRC slabs
FIGURE 4. Comparison of load values at rst and ultimate cracks
FIGURE 5. Comparison of deection values at rst and ultimate cracks

199
TABLE 7. Experimental results of load-carrying capacities (Pcr) and deections of slab specimens
Slab Label First Crack Load Pcr
(KN)
Crushing Load Pult
(KN)
Deection at First Crack
(mm)
Deection at the nal crack
(mm)
SM1 79.05 89.21 3.9 6.93
SM2 72.33 91.45 3.5 7.38
SM3 91.13 101.49 6.04 15.1
SM4 72.49 110.57 6 17.8
SM5 68.01 98.81 5.3 14.18
SM6 90.25 117.29 6.92 18.9
SM7 65.77 83.69 6.5 8.5
SM8 61.29 103.77 3.9 13.2
SM9 32.17 91.13 3.55 13.2
SM10 47.85 97.85 3.18 15.6
SM11 59.05 99.37 4.9 11.4
SM12 81.45 115.05 5.35 14.78
SM13 62.33 97.25 3.55 9.3
SM14 56.81 74.73 3.6 8.5
SM15 36.65 71.29 3.14 8.3
SM16 53.21 61.13 5.3 9.15
SM17 56.81 88.01 3.75 7.7
SM18 63.37 76.81 5.8 12.3
SM19 90.25 112.81 6.45 11.7
SM20 54.57 69.05 7.1 10.6
SM21 56.65 64.81 4.4 8.3
FIGURE 6. Load-deection curves for 0.7 % Steel Fiber Samples with (a) Without Fibers Sample (b) 0.1% PPF
(c) 0.3% PPF (d) 0.5% PPF (e) 0.7% PPF and (f) 0.9% PPF

200
FIGURE 7. Load-deection curves for 0.8 % Steel Fiber Samples with (a) Without Fibers Sample (b) 0.1% PPF
(c) 0.3% PPF (d) 0.5% PPF (e) 0.7% PPF and (f) 0.9% PPF
FIGURE 8. Load-deection curves for 0.9 % Steel Fiber Samples with (a) Without Fibers Sample (b) 0.1% PPF
(c) 0.3% PPF (d) 0.5% PPF (e) 0.7% PPF and (f) 0.9% PPF
FIGURE 9. Load-deection curves for 1.0 % Steel Fiber Samples with (a) Without Fibers Sample (b) 0.1% PPF
(c) 0.3% PPF (d) 0.5% PPF (e) 0.7% PPF and (f) 0.9% PPF

201
SM1 SM2 SM3
SM4 SM5 SM6
SM7 SM8 SM9
SM10 SM11 SM12
SM13 SM14 SM15
SM16 SM17 SM18
SM19 SM20 SM21
FIGURE 10. Failure modes and cracks patterns of slabs

202
CONCLUSIONS
Twenty-one RC one-way slab specimens with dierent
ratios of steel and PPF were cast to determine the optimum
contents of bers for the maximum load-carrying capacity
and ductility of RC slabs. The specimens were tested
under four-point exural loading and the load-deection
response and failure behavior were studied. The following
conclusions can be deduced from the presented work:
1. The increase in the percentage of bers does not
necessarily lead to an increase in the exural strength of
the specimen. With the use of 0.7% of SF, the optimum
results of the load-carrying capacity of 117.29 kN were
produced by using 0.9% PPF. With the use of 0.8% SF,
the optimum results of the loading capacity of 103.77
kN were produced using 0.3%. With the use of 0.9%
SF, the optimum results of the loading capacity of 115
kN were produced using 0.1% PPF. With the use of 1%
steel ber, 0.5% of PPF produced the optimum result
of 112.81 kN. The maximum load-carrying capacity of
slabs was obtained at the ber’s combination of 0.7%
SF and 0.9% PPF that was 131% of that of RC slab
without bers.
2. The optimum ber content depends upon the mix ratio
and the procedure used to carry out the mixing. The
larger contents of bers will lead to the balling and a
thicker mix by reducing the workability. A percentage
decrease of 188% occurred in the slump value of
concrete when the SF increased from 0% to 1.0% and
PPF increased from 0% to 0.9%.
3. The reduction in the cracking and deection is greatly
dependent upon the ber distribution on the cross-
section under consideration. We can observe that
while using 0.7% SF, the deection at ultimate loading
is increased with the increase of PPF by 101.89%.
Similarly, when the PPF along with 0.8% SF, were
increased from 0.1% to 0.9%, the eect of increasing
the PPF on the rst crack deection was decreasing
from 6.5 mm to 3.8 mm but on the deection at ultimate
loading capacity was in the form of an increasing trend
from 8.5 mm to 15.6 mm. The eect of PPF along
with the combination of 0.9% SF, their eect on the
deection at ultimate crack loading was similar to that of
eect at 0.8% SF; by increasing the PPF, the deection
at ultimate crack loads was decreased by 14.78 mm to
9.15 mm. Moreover, when the combinations of 1.0%
SF with dierent increasing quantities of PPF were
used, the deection at ultimate crack loads was rst
increased up to 7.7 mm to 11.7 mm using 0.3% PPF
quantity and then started to decrease by 48.19% at 0.9%
PPF. The proper dispersion of bers should be devised
to get a uniform specimen. The results showed that by
using hooked-steel bers along with the PPF preserved
the high-performance fresh properties of concrete and
obtained a reliable behavior in the fracture results.
4. The outcomes of present work will help to introduce the
HFRC in the construction industry, especially for one-
way RC slabs, with reasonable condence.
ACKNOWLEDGMENTS
The authors gratefully acknowledge the UET Taxila for
testing facility.
DECLARATION OF COMPETING INTEREST
None.
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