DURABILIDAD.pdf

Mechanical, durability, and microstructural properties of macro
synthetic polypropylene (PP) fiber-reinforced rubber concrete
Jiaqing Wang, Qingli Dai*
, Ruizhe Si, Shuaicheng Guo
Department of Civil and Environmental Engineering, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, 49931, USA
a r t i c l e i n f o
Article history:
Received 26 February 2019
Received in revised form
20 June 2019
Accepted 23 June 2019
Available online 26 June 2019
Handling Editor: Prof. Jiri Jaromir Kleme
s
Keywords:
Fiber-reinforced rubber concrete
Mechanical property
Durability performance
Microstructure
Fracture morphology
Environmental protection
a b s t r a c t
In this study, the synergistic effect of combining macro polypropylene (PP) fiber and rubberized concrete
was evaluated based on mechanical and durability performance, as well as microstructure. The speci-
mens were prepared with two different rubber volume contents at 10% and 15%, incorporating with a
consistent fiber volume fraction of 0.5%. The plain concrete specimens and specimens with only PP fiber
were also produced for comparison. The mechanical test results indicated that the fracture energy of
plain concrete could be enhanced with both macro PP fiber and rubber aggregates. Besides, all specimens
achieved compressive strength higher than 40 Mpa, and the ultrasonic pulse velocity demonstrated the
good quality of concrete specimens. The fracture morphology and ESEM imaging showed the positive
function of rubber aggregates and PP fibers on the post-crack propagation. The durability performance,
including drying shrinkage, ASR expansion, and frost resistance were also strengthened in macro PP
fiber-reinforced rubber concrete compared with plain concrete. The macro PP fiber-reinforced rubber
concrete will enlarge the post-failure flexural residual load capacity and deformation and distribute
stress for multiple crack propagation, thus increasing overall fracture toughness and reducing brittleness.
The sustainable applications can be further explored with the combination of macro PP fiber and recycled
rubber aggregate.
Published by Elsevier Ltd.
1. Introduction
Recently, with the rapid development of the motor industry, a
number of waste tires are generated every year in the United States.
From the U.S scrap tire management summary, there were more
than 250 millions of scrap tires produced in 2017 (Association,
2018). Regarding civil engineering market, only 8% of the total
scrap tires of 2017 were employed, such as rubber modified asphalt
binder and rubberized cementitious materials (Presti, 2013;
Siddique and Naik, 2004). Even though the different recycling
procedures consumed a considerable volume of scrap tires, there
are still 40 millions of scrap tire, which was 16% of total generated
tires, were subjected to landfilling disposal in 2017. However, the
landfill process of solid waste is becoming unacceptable since the
increasing cost and limited available land disposal sites (Eldin and
Piekarski, 1993). Hence, to minimize the environmental impacts,
some investigations have been performed to evaluate the physical
properties and durability performance of concrete containing
recycled scrap tire rubbers as an alternative for traditional aggre-
gates. The production process of crumb rubber aggregates was
concluded and reported by Sunthopagasit and Duffey
(Sunthonpagasit and Duffey, 2004), the recycled tires are firstly de-
rimmed to remove metal stream (tire wire), which are then intro-
duced to the tire conveying system. The whole tires are divided into
various sizes after the shredding and granulating processes. During
the aforementioned processes, the magnet is used as metal
remover to eliminate steel wires, and the fiber-screening system is
incorporated to separate fibers from rubber particles. About 99.9%
metal and 90% fiber are removed. Finally, the crumb rubber parti-
cles are divided into different sizes in a range of 5e30 mesh, which
can be implemented as rubber aggregates. Some properties of plain
concrete can be improved by adding rubber aggregates, such as
energy absorption, freeze-thaw resistance, and toughness (Ho et al.,
2012; Segre and Joekes, 2000; You et al., 2019). However, the
strength of plain concrete can be dramatically reduced with high
contents of rubber aggregates (Guo et al., 2017; Khatib and Bayomy,
1999; Reda Taha et al., 2008a), the optimum rubber content should
* Corresponding author. Department of Civil and Environmental Engineering,
Michigan Technological University, 1400, Townsend Dr., Houghton, MI, 49931, USA.
E-mail addresses: jiaqingw@mtu.edu (J. Wang), qingdai@mtu.edu (Q. Dai),
ruizhes@mtu.edu (R. Si), sguo3@mtu.edu (S. Guo).
Contents lists available at ScienceDirect
Journal of Cleaner Production
journal homepage: www.elsevier.com/locate/jclepro
https://doi.org/10.1016/j.jclepro.2019.06.272
0959-6526/Published by Elsevier Ltd.
Journal of Cleaner Production 234 (2019) 1351e1364

be considered when producing rubberized concrete. Additionally,
with the elastic rubber aggregates, the drying shrinkage of plain
concrete can also be increased since the soft rubber is easily
deformed under internal shrinkage stress when compared with the
classical gravel or sand (Sukontasukkul and Tiamlom, 2012; Yung
et al., 2013). These negative effects of rubber aggregates limited
the wide application of rubberized concrete despite its advantages
and environmental profit. Some researchers have reported that the
chemical surface treatment on rubber aggregates could improve
the mechanical property of the rubber concrete (Dong et al., 2013;
Meddah et al., 2014b; Pelisser et al., 2011; Segre and Joekes, 2000).
The most widely utilized method within these studies is by
immersing rubber particles with NaOH solution (40 g/L) before
employing them into concrete mix, which will modify the hydro-
phobic property of rubber surface and make it hydrophilic. Sub-
sequently, denser cement hydration products will be generated
around the rubber particle and contribute to a better bond between
each other. The test results demonstrated that the reduction of
strength by introducing virgin rubber aggregates could be poten-
tially decreased in company with NaOH solution treated rubbers
(Meddah et al., 2014b; Pelisser et al., 2011).
With the development of concrete technology, the poly-
propylene (PP) fibers have been extensively used in concrete
structures for property and durability enhancement. The PP fibers
can be divided in forms of micro PP fibers and macro PP fibers.
Commercially, the micro PP fibers with a diameter range from 5 to
100 mm and length from 5 to 30 mm (Yin et al., 2015), are selected
for restraining the plastic shrinkage cracking at a low volume
content (Alhozaimy et al., 1996; Banthia and Gupta, 2006). The
superiority of micro PP fibers regarding the shrinkage crack con-
trolling and the durability performance were broadly reported
(Grzybowski and Shah, 1990; Kim et al., 2010). However, the me-
chanical properties of concrete are not expected to be significantly
enhanced by the application of micro PP fibers (Zollo, 1997). The
mechanical properties of micro PP fiber-reinforced concrete were
investigated by A.M. Alhozaimy (Alhozaimy et al., 1996), the
collated fibrillated micro PP fibers were added at a relatively low
volume fraction from 0% to 0.3% based on the total volume of the
mixture. The test results showed that the fiber contents did not
have a statistically significant effect on the compressive strength of
plain concrete. At the same time, the flexural strength of plain
concrete was also not statistically affected by the fiber contents. The
macro PP fibers generally have a length of 30e60 mm and cross-
section of 0.6e1 mm2
(Yin et al., 2015). Hsie et al. studied the me-
chanical properties of macro PP fiber-reinforced concrete (Hsie
et al., 2008b), the results showed that the macro PP fiber can
slightly increase the flexural strength of plain concrete and mini-
mize the brittle flexural failure of ordinary concrete. Fraternali et al.
studied the post-crack performance of macro PP-fiber reinforced
concrete. It was found that the ductility of plain concrete could be
significantly improved with the introduction of 1% macro PP fiber
(Fraternali et al., 2011). The macro PP fiber could not only contribute
to the plastic shrinkage controlling, but also the drying shrinkage
could be limited. The drying shrinkage behavior of macro PP-fiber
reinforced concrete at three different volume fractions of 0.5%,
0.75%, and 1.0% was studied by Sung Bae Kim et al. (Kim et al., 2010).
It was found that the drying shrinkage strain was decreased with
increased fiber volume fraction. The cost and environmental ben-
efits of using macro PP fibers have attracted more attention rather
than micro PP fibers in recent years (Yin et al., 2015). The PP fibers
have significantly low cost compared to steel, the use of macro PP
fiber could achieve a similar level of reinforcement in concrete at a
half price of using steel, and the labor cost will also be reduced with
the application of macro PP fiber reinforcement (Ochi et al., 2007).
In the meanwhile, the corrosion of steel reinforcement could be
mitigated with using macro PP fibers, thus contributing to better
durability. On top of that, the production of PP fiber can reduce the
carbon footprint when compared with that of operating steel (Shen
et al., 2010). Therefore, the macro PP fiber could become an effec-
tive alternative to conventional steel reinforcement with relatively
low cost and environmental benefits.
In regard to the current knowledge on this topic, this paper
would provide a detailed investigation of mechanical and durability
performance of macro PP fiber-reinforced rubber concrete. From
the current literature review, the addition of treated rubber
aggregate could slightly help to modify the brittleness of plain
concrete, however, this improvement was not obvious and thus the
rubberized concrete cannot be facilitated in a wide application. In
this study, the introduction of macro-PP fiber into rubberized
concrete can substantially improve fracture performance of
rubberized concrete. The good workability was sustained after the
combination of macro PP fiber and rubber aggregate. From the
mechanical tests and microstructure observation, the mechanism
of improved fracture property by combining macro PP fiber and
treated rubber aggregate was revealed. Most of the mechanical
strength was remained after combining macro PP fiber and treated
rubber aggregate in concrete. The post-failure fracture behavior
was not only modified by rubber but also improved with the
increased residual load and deformation through fiber-bridge ef-
fect. Finally, the added fiber can offset the increased drying
shrinkage in rubberized concrete, which also demonstrated the
synergy effect between macro PP fiber and rubber aggregate. This
macro PP fiber reinforced concrete material can be extended to a
wider application than the secondary structures in the current
situation.
In this investigation, the surface treated scrap tire aggregates
(mesh size #7 to #30) were selected to partially replace the tradi-
tional fine aggregates at optimum fractions of 10% and 15% in macro
PP fiber-reinforced concrete samples, where the fiber volume
fraction was controlled consistently at 0.5% of the total volume of
the mixture. The microstructure, mechanical, and durability prop-
erties of PP fiber-reinforced rubber concrete were thoroughly
investigated.
2. Materials and test methods
2.1. The preparation of materials and mixture designs
2.1.1. The selection and preparation of materials
In this study, the regular Type I portland cement that meets the
specifications in ASTM C150 standard (Standard, ASTM C150, 2017)
was used as the binder, the chemical compositions are shown in
Table 1. The size range of recycled tire rubber used in this investi-
gation is from mesh size #7 to #30. All rubber particles were pre-
treated by emerging with 1 N (40 g/L) NaOH solution for 20 min (Si
et al., 2018), and then cleaned with tap water and air-dried before
mixing procedures. After that, the gradation of the coarse aggre-
gates is shown in Table 2. The sieve analysis was performed on
natural river sand and recycled rubber aggregate as shown in Fig. 1.
The gradation of both coarse aggregate and river sand obeyed
requirement in the ASTM C33 standard (Standard, ASTM C33, 2018).
The river sands were prepared to surface saturated dry (SSD)
condition before mixing, which had a water absorption rate about
Table 1
The chemical compositions of participated cement.
CaO SiO2 Al2O3 Na2O þ K2O Fe2O3
Type I portland cement 62.8% 19.4% 4.9% N/A 2.8%
J. Wang et al. / Journal of Cleaner Production 234 (2019) 1351e1364
1352

1.8% that measured by following ASTM C128 standard (Standard,
ASTM C128, 2015). The air entrainer that used in this study is light
brown liquid, which has a specific gravity of 1 ± 0.02 and a pH-
value of 10.5 ± 1. The polycarboxylate-based high-range water
reducer is blue liquid with a pH-value of 6 and a specific gravity of
1.1. The macro PP fiber that applied in this investigation was
twisted-bundle monofilament and fibrillated fibers. The physical
properties of this kind of PP fiber are listed in Table 3, and the
schematic is showed in Fig. 2. This kind of PP fiber also has ad-
vantages that suitable for use in concrete, including electrical
insulation and hydrophobic property (Ahmed Dabbak et al., 2018;
Mohod, 2015).
2.1.2. The mixture designs and sample types
The mixture designs of different types of concrete specimens are
demonstrated in Table 4. The group “CO” was plain concrete as the
control group, the group “PP” was PP fiber reinforced concrete
samples without rubber, and the group “FR-10” and “FR-15” was PP
fiber reinforced concrete samples with partial replacement of river
sand by 10% and 15% rubber aggregates based on the total volume
of fine aggregate, respectively. The air entrainer and
polycarboxylate-based high-range water reducer (HRWR) were
applied to improve the workability and also air content. The con-
tents of air entrainer and HRWR were kept consistent in all groups
to limit the variations. The target water to cement ratio was
designed as 0.44. The fiber amount was selected considering two
aspects. On the one hand, 0.4e0.7% of synthetic fibers have been
found to provide significant improvements on toughness after
cracking and better crack controlling as reported by ACI 544.1R
(ACI, 2009). On the other hand, taking into account the impact of
fibers on the rheology of concrete mixtures, the fiber amount
should be controlled in a relatively low level (0.5% (Zollo,1997)) to
sustain good workability. Therefore, the 0.5% of fiber reinforcement
volume was determined for this study.
Table 2
The gradation of coarse aggregates.
Sieve Size Weight percent retained on (%)
3/4 in (19.0 mm) 5
1/2 in (12.7 mm) 25
3/8 in (9.51 mm) 25
No. 4 (4.76 mm) 20
No. 8 (2.38 mm) 16
No. 16 (1.19 mm) 9
Fig. 1. Sieve analysis on different fine aggregates.
Table 3
The physical properties of macro PP fiber.
Physical properties
Length (mm) 38
Tensile strength (MPa) 570e660
Elastic modulus (GPa) 4.7
Specific gravity 0.91
Resistance to acid alkali Excellent
Water absorption No
Fig. 2. The schematic of macro-hybrid shapes PP fiber.
J. Wang et al. / Journal of Cleaner Production 234 (2019) 1351e1364 1353

In the case of the mortar samples that subjected to the durability
tests (drying shrinkage and ASR expansion), the mixture designs
are shown in Table 5. The types of cement, sands, rubbers, and PP
fiber were selected as same as that used in the concrete mixtures.
2.2. Test methods
2.2.1. Fresh property
The fresh properties are measured immediately after the mixing
procedure, the slump, unit weight, and air voids were obtained by
following the ASTM C143 (ASTM, 2015), ASTM C231 (ASTM, 2017b),
and ASTM C138 standard (ASTM, 2017a), respectively.
2.2.2. Compressive strength test
The compressive strength was tested by following the ASTM C39
standard (Standard, ASTM C39, 2018). The concrete specimens with
the dimensions of 102 mm diameter by 204 mm height were pro-
duced based on the same procedures and then removed from the
molds after 22 ± 2 h after casting, and finally cured under water
bath at the room temperature of 21 ± 2 C until the testing time.
The compressive test was conducted at corresponding curing time
in 3, 7,14, 28 days. The load frame rate was controlled as 0.24 MPa/s,
and the compressive strength of each type of samples was
computed by the average strength of three concrete cylinders.
2.2.3. Splitting tensile strength test
The splitting tensile strength was then be investigated based on
the ASTM C496 standard (ASTM, 2017c) at 28 days. The same
sample sizes were used as presented in compressive strength test.
The peak load was recorded to calculate the splitting tensile
strength by following equation (1), and the average strength was
based on three samples.
fsp ¼ 2P=ðpDLÞ (1)
where, fsp ¼ splitting tensile strength (Mpa), P ¼ peak load at
failure point (N), D ¼ diameter of the cylinder (mm), and L
¼ height of the cylinder (mm).
2.2.4. Flexural test (three-point bending subjected on single edge
notched beam)
In this study, the flexural behaviors of different types of speci-
mens were evaluated by following the JCI-002-2003 standard
(Standard, 2003), the single-edge notched concrete beams were
prepared with dimensions of 102 mm by 102 mm cross-section and
381 mm length. Three concrete beams were produced for each type
of samples. All samples were cured for 28 days before conducting
the test, and the notched cracks were sawed one day before the test.
The crack was prepared with a concrete saw, which has a crack
depth of 30 ± 2 mm and crack width of 5 mm. The fixtures for
holding the displacement gauge were glued near the crack, and the
gauge was settled on the fixtures during the test and connected
with the data collection system, which has data acquisition rate of
10 Hz. The three-point bending test was then conducted on an
Instron 4206 testing system with a span length of 305 mm. An
increased loading rate at 1.25 mm/min was applied, which was
about three times higher than the suggested loading rate in the JCI
standard, but as long as the Load-CMOD curve was not substantially
affected, the rate could be increased as noted in prescribed stan-
dard. The loading crosshead was limited to stop once the crack
mouth opening displacement (CMOD) reached 10 mm. The sche-
matic of the testing establishment is shown in Fig. 3.
2.2.5. Microscope and SEM imaging analysis of fracture sample
surfaces
The fracture surfaces of PP-fiber reinforced concrete samples
with 15% rubber content were observed after compressive strength
test. To discover the bonding behavior between treated rubber
aggregates and cement paste, and investigate the stress-releasing
effect by rubber particles, the image analysis was conducted with
an Environmental Scanning Electron Microscope (ESEM) and op-
tical microscope.
Table 4
The mixture designs of different concrete samples (Unit: kg/m3
).
Mixture
ID
Designed Fiber Content
(vol. %)
Target
w/c
Water Air entrainer (ml/kg
cement)
High-range Water
reducer
Portland
cement
Coarse
aggregate
Fine
aggregate
Rubber PP
Fiber
CO 0.0 0.44 154.3 1.50 1.74 385.0 960.0 815.0 N/A N/A
PP 0.5 0.44 154.3 1.50 1.74 385.0 960.0 815.0 N/A 4.5
FR-10 0.5 0.44 154.3 1.50 1.74 385.0 960.0 733.5 35.4 4.5
FR-15 0.5 0.44 154.3 1.50 1.74 385.0 960.0 692.8 53.1 4.5
Table 5
The mixture designs of mortar samples (w/c ratio ¼ 0.50, designed volume: 2100 cm3
).
Mix ID Cement (g) Sand (g) Water (g) Rubber (g) Fiber (g)
Without rubber (“COM”) 1200 3000 600 N/A N/A
With 15% rubber (“ROM”) 1200 2550 600 192 N/A
With 15% rubber and PP fiber (“FRM”) 1200 2550 600 192 9.6
Fig. 3. Flexural test set up.
1354

2.2.6. Ultrasonic wave transmission speed
The ultrasonic wave transmission velocity was measured after
28 days curing by following the methods that applied by Guo and
Dai (Guo et al., 2016), the solid concrete slides were cut from cyl-
inder samples (102 mm diameter) with a thickness of 30±5 mm.
Two Olympus 5077 transducers were subjected to top and bottom
sides of concrete slides with a frequency at 0.5 MHz, the pulse
speed was then computed with an average of three samples.
2.2.7. Bulk electrical resistivity test
The bulk electrical resistivity of concrete samples was measured
at 28 days by using the uniaxial method (Layssi et al., 2015). The
sweep frequency from 10 Hz to 10 kHz was applied to all concrete
cylinder specimens (102 mm diameter by 204 mm height). The
bulk electrical resistivity was then calculated based on the average
of the resistance measurement at various frequency. The terminate
results were obtained by the average of three cylinder specimens in
the corresponding group.
2.2.8. Drying shrinkage test
The drying shrinkage behaviors of mortar samples were inves-
tigated based on the ASTM C157 standard (Standard, ASTM C157,
2017). The test specimens were produced and molded with the
dimensions of 25 mm by 25 mm cross-section area and 286 mm
length for each type of samples. The specimens were removed from
the molds after 24 h curing and saved in the curing chamber with a
relative humidity of 50 ± 5% at a temperature of 23 ± 2 C. The
initial length of each specimen was measured immediately after
demolding. Afterward, the length changes were measured at 1, 3, 5,
7, 11, 14, and 21 days with the consistent curing circumstance.
2.2.9. ASR expansion test
The rapid alkali-silica reaction (ASR) test was conducted by
following the ASTM C1260 standard (Standard, ASTM C1260, 2014).
The specimens were prepared with the same dimensions as
described in the drying shrinkage test. All test specimens were
demolded after 24 h curing and immediately cured by tap water in
a plastic container for another 1 day in an oven at 80 C. Thereafter,
the initial measurement was conducted with all specimens, and
then the specimens emerged into another container with 1 N (40 g/
L) NaOH solution. All samples were measured by following the
procedures required in the standard at 1, 3, 5, 7, 11, and 14 days. The
length expansion was computed based on the average of three
samples for each group.
2.2.10. Freeze-thaw resistance test
In this investigation, the prepared concrete specimens with
76 mm by 102 mm by 381 mm dimensions were subjected to the
freeze-thaw chamber in accordance with ASTM C666-15 standard,
method B (Standard, ASTM C666, 2015). After 28 days curing under
water at 22 ± 2 C, the initial mass weight, length, and resonant
frequency of samples were measured before storing into the
chamber. During the freeze-thaw processes, the dynamic modulus
of elasticity and length change was measured after different frost
periods of 0, 36, 50, 100, 150, 200, 250, and 300 cycles. The results
are reported based on the average of three concrete beams.
3. Test results and discussion
3.1. Fresh properties
The evaluation results on the fresh properties are summarized
in Fig. 4. Regarding the workability, the slump values of all fresh
mixture are between 16.5 cm and 20 cm as shown in Fig. 4 a), which
represented excellent workability subjected to most types of con-
struction requirements. After the implementation of macro PP fi-
bers into mixtures, the slump was reduced by 1.7 cm compared
with that of control mixtures. Furthermore, the slump of fresh
mixtures with the combination of PP fibers and rubber aggregates
was furtherly decreased, the slump was 17.6 cm and 16.5 cm of
fiber-reinforced concrete samples incorporated with 10% and 15%
rubber aggregates. The reduced workability attributes to the fric-
tions between rubber particles and the mobility restriction of
macro PP fibers to the movement of the coarse particles (Hsie et al.,
2008a). Thus, the workability of plain concrete will be decreased
after adding macro PP fiber and rubber aggregates, but the reduced
workability will still sustain in a good level (17.6 cme16.5 cm) for
wide application. In practice, the fiber-reinforced concrete always
showed lower workability than plain concrete (Libre et al., 2011),
but the proper vibration method will result in good placement and
uniformity (Gettu et al., 2005).
In the case of air voids content as illustrated in Fig. 4 a), the
introduced PP fibers and rubber aggregates both contribute to the
air voids increase. The plain mixture showed the lowest air voids
content of 3.2% and the “FR-15” mixture represented the highest air
voids content of 4.2%. The rubber and fibers can entrap more air
during the mixing processes.
The unit weight of plain concrete also decreased with the
introduction of macro PP fiber and rubber aggregates as shown in
Fig. 4 b). On the one hand, the aforementioned air voids increase
can slightly affect the unit weight. On the other hand, the lower
specific gravity of rubber aggregates comparing to that of original
river sands also attributed to the density reduction.
20
18.3
17.6
16.5
3.2
3.7
4.1
4.2
CO PP FR-10 FR-15
15.0
16.5
18.0
19.5
21.0
Mixutre types
Slump
(cm)
Slump
Air voids
2.8
3.0
3.2
3.4
3.6
3.8
4.0
4.2
4.4
4.6
Air
voids
(%)
CO PP FR-10 FR-15
1000
1200
1400
1600
1800
2000
2200
2400
b)
2015.7
2082.4
2149.1
Unit
weight
(kg/m
3
)
Mixture types
2242.6
a)
Fig. 4. Fresh property test results: a) Slump and air voids of fresh mixtures; b) Unit weight (density) of fresh mixtures.

3.2. Mechanical properties and fracture surface microstructures
3.2.1. Compressive strength
As shown in Fig. 5, the control specimens obtained the highest
strength of 57.3Mpa after 28 days. With the introduction of PP fiber,
the compressive strength was not apparently affected, which was
minor reduced about 1.6% based on that of control samples. Since
the introduction of PP fibers at 0.5% volume content, the elastic
modulus of the entire concrete matrix could be affected and slightly
reduced (Bayasi and Zeng,1993), thus had a small negative effect on
the compressive strength. Once the rubber aggregate was added,
the compressive strength was obviously reduced when compared
with the results of control specimens or PP fiber reinforced speci-
mens. The 28 days compressive strength of specimens that con-
taining 10% and 15% was 42.5Mpa and 41.7Mpa, respectively. The
low stiffness rubber aggregates reduced the compressive strength
since the soft rubber particles can be easily deformed under
compression (Albano et al., 2005; Eldin and Senouci, 1993). These
soft rubber filled areas were likely to form stress concentration, and
cracks could be produced near these areas (Kotresh and Belachew,
2014; Reda Taha et al., 2008a). Also, the integrity of the concrete
specimens could be affected with the added rubber, the elastic
modulus could be significantly reduced, and the stiffness of the
whole concrete matrix was then reduced (Meddah et al., 2014a).
However, the compressive strength reached 41.7 Mpa even if with
the replacement of 15% soft rubber particles at 28 days. Therefore,
all of the PP-fiber reinforced rubber concrete specimens that pro-
duced in this investigation can be classified as high-strength con-
crete (28 days compressive strength 40 Mpa, based on the ACI
report (363, 2010)).
3.2.2. Splitting tensile strength and fracture morphology
observation
The splitting tensile strength of each type of specimens is
calculated and plotted in Fig. 6. The splitting tensile strength of PP-
fiber reinforced specimens was slightly increased but almost kept
at the same level when compared with that of control specimens.
As expected, the introduced rubber aggregates reduced the split-
ting tensile strength with the increasing of rubber contents. The
splitting tensile strength of PP fiber reinforced rubber concrete
specimens that containing 10% rubbers and 15% rubbers was
reduced about 9.5% and 21.5% compared with that of plain concrete
specimens, respectively. Compared with relevant literature,
Ganjian et al. (2009) revealed that the tensile strength of rubber-
ized concrete samples with 10% replacement of coarse aggregate
was about 50% lower than that of plain concrete samples. Ho et al.
(2012) illustrated that the splitting tensile strength of ordinary
concrete can be reduced about 26% after incorporating with 20%
rubber aggregate to replace sand. Even if the PP-fiber has consid-
erable tensile strength, the brittle cement paste is not aimed to
resist the tensile force and therein the initiation of cracks is still
controlled by the quality of the cement matrix, the maximum load
normally happened when the main crack occurred in the cement
paste. However, after the crack happened, the fiber bridging effect
could play a critical role in controlling the rapid development of the
crack. Therefore, the PP-fiber did not obviously improve the split-
ting tensile strength of the original concrete, but it dramatically
contributed to the crack controlling.
Distinct failure behaviors of different types of concrete speci-
mens were observed after splitting tensile tests. As shown in
Fig. 7a), the control specimen showed the apparent brittle failure.
However, after the introduction of ductile fibers, the failure
behavior of the PP fiber reinforced sample was changed, the sig-
nificant post-crack displacement was observed as shown in Fig. 7b).
The fracture morphology supported that the fibers can bridge the
crack and keep the concrete specimen to sustain considerable load
after the first crack happening. Besides, when introduced rubber
aggregates, the better post-crack behavior was then found, the
large main single crack that observed in the samples of the “PP”
group was mitigated. The distributed cracks were developed since
rubber released internal stresses.
The fracture surfaces of PP fiber-reinforced rubber concrete was
then observed by the optical microscope after the splitting tensile
test. Fig. 8a) shows the different failure behaviors of fibers, some of
them were pulled-out, and some of them were ruptured, the fiber-
bridging effect was observed as macro PP fibers restrained the
broken piece of the cement matrix. Due to the bond strength be-
tween rubber and cement matrix was not good as the conventional
aggregates and the relatively low stiffness of rubber, some rubber
particles presented debonding behavior with cement matrix rather
than broken itself, which is shown in Fig. 8b). However, there are
also some benefits with the elastic rubber particles. The rubber
3 7 14 28
0
10
20
30
40
50
60
Compressive
strength
(Mpa)
Curing time (days)
CO
PP
FR-10
FR-15
Fig. 5. The compressive strength of different types of samples.
CO PP FR-10 FR-15
0
2
4
6
28
days
splitting
tensile
strength
(Mpa)
Specimens
28 days splitting tensile strength
Fig. 6. Splitting tensile strength test results.
1356

particles could arrest brittle crack and reduce the development of
the cracks, as shown in Fig. 8c) and d). Thereafter the growth speed
and the size of the main crack could be minimized with the pres-
ence of randomly distributed rubber particles, thus improving the
toughness of the concrete matrix when compared with plain con-
crete (Khaloo et al., 2008).
3.2.3. Flexural strength and fracture energy
3.2.3.1. Flexural behavior and failure patterns. The typical relation-
ship between the applied load and crack mouth opening
displacement (CMOD) of different types of concrete samples were
demonstrated in Fig. 9. It is obvious to observe that the brittle
failure of the control specimens in “CO” group, the Load-CMOD
curve rapidly dropped down once it reached the peak load, and
the CMOD value was only 0.37 mm upon failure. However, the
situation was totally changed after the introduction of PP fiber, the
desirable post-crack extension was found in the Load-CMOD curve
of specimens in “PP” group. After the crack initiation, the load did
not rapidly drop, but sustained in a considerable post-cracking
residual load and gradually reduced with the increasing of CMOD
value. Since the presence of randomly distributed long fibers, even
if the crack developed, the fibers can bridge the crack and resist the
growth of the crack. Furthermore, with the implement of elastic
soft rubber particles in “FR-10” and “FR-15” group, the trend of the
reduction in the post-cracking residual load was furtherly modified,
which represented a higher residual load and a lower reducing
slope when compared with the Load-CMOD curve of specimen only
containing PP fibers. The specimens of “FR-15” group with the
addition of 15% rubber particles and PP fiber represented the
highest post-cracking residual load before failure. The deformable
rubber particles could help to release the concentrated internal
stress.
After the test, the failure behaviors of different types of samples
were also detected. Regarding the formation of the crack in the
control sample, only a small single crack was found as shown in
Fig. 10c), a sharp crack tip and obvious brittle failure were observed
as shown in Fig. 10a). Nevertheless, with the combination of macro
PP fibers and elastic rubber aggregates, the failure mode and the
crack formation situation were obviously adjusted. As shown in
Fig. 10d), the crack formation of “PP” samples, the fiber bridging
effect can be verified by the significant opening crack mouth,
however, the sharpness of the crack did not change when
compared with the “CO” sample. After combining rubber and
macro PP fiber, the formation path of the crack was modified with
the stress releasing effect of elastic rubbers (Khorrami et al., 2010;
Mohammadi et al., 2014). Besides the main opened crack, a few of
Fig. 7. The fractured sample morphology: a) Failed “CO” specimen; b) Failed “PP” specimen; c) Failed “FR-10” specimen.
Fig. 8. Optical microscope observation of fracture surfaces on PP-fiber reinforced
rubber concrete: a) Fiber pullout or bridging cracks with brittle cement matrix; b)
Debonded rubber particles due to different stiffness between cement matrix and
rubber particles; c) Rubber particle blocked the crack development; d) Crack arrested
by deformable rubber particles.
0 2 4 6 8 10
0
1000
2000
3000
4000
5000
6000
7000
The post-peak residual load was
furthrly increased incorporating
with rubber aggregate
0.0 0.2 0.4 0.6 0.8 1.0
2000
3000
4000
5000
6000
Load
(N)
CMOD (mm)
CO
PP
FR-10
FR-15
Load
(N)
CMOD (mm)
The brittle flexural failure
was eliminated
with macro PP fiber
Zoom In
Fig. 9. Typical load-CMOD curves of different concrete specimens.

distributed small cracks can be found near the main crack as shown
in Fig. 10e), and the crack tip sharpness was also decreased.
3.2.3.2. Flexural strength and fracture energy. The flexural strength
and fracture energy were calculated based on the Load-COMD
curves and dimensions of corresponding concrete beam samples,
the results were obtained from the average of three samples in each
group. The flexural strength was calculated based on equation (2):
s ¼ 3FL
.
2bh2

(2)
where, F ¼ Peak load (N), L ¼ Span length (mm), b ¼ width of the
broken ligament (mm), h ¼ height of the broken ligament (mm).
The calculated results are demonstrated in Fig. 11. With the
application of PP fiber, the average flexural strength of samples in
“PP” group was slightly increased, but almost equal to that of
control samples in “CO” group. The previous study found that the
macro PP fiber can significantly contribute to the crack controlling,
but not obviously useful for improving the flexural strength
(Banthia and Soleimani, 2005). In consistent with previous study,
the flexural strength of concrete specimens containing PP fiber did
not show obvious enhancement in the flexural strength compared
with that of control samples. However, after adding rubber aggre-
gates, the flexural strength of PP fiber-reinforced rubber concrete
samples was reduced as expected. The strength of specimens in
“FR-10” and “FR-15” groups reduced about 12.8% and 21.6% when
compared with the strength of control samples, respectively.
Simultaneously, the fracture energy was calculated based on the
equation from the JCI-002-2003 standard (Standard, 2003) as
expressed in equation (3):
8

:
GF ¼
0:75W0 þ w1
Alig
W1 ¼ 0:75

S
L
m1 þ 2m2

g,CMODC
(3)
where, GF ¼ fracture energy (N/mm), W0 ¼ area below CMOD curve
up to rupture of specimen (N*mm), W1 ¼ work done by dead
weight of specimen and loading fixture (N*mm), Alig ¼ area of
broken ligament (b*h) (mm2
); m1 ¼ mass of specimen (kg),
S ¼ loading span (mm); L ¼ total length of specimen (mm),
m2 ¼ mass of jig not attached to testing machine but placed on
specimen until rupture (kg), g ¼ gravitational acceleration
(9.807 m/s2
), CMODc ¼ crack mouth opening displacement at the
time of rupture (mm).
The fracture energy of different types of concrete specimens was
concluded as shown in Fig. 12. It is evident that the fracture energy
of plain concrete samples in “CO” group was dramatically improved
with the application of PP-fiber reinforcement, the fracture energy
of specimens in “PP” group showed about 15 times higher fracture
energy when compared with control samples (From 0.133 N/mm to
2.03 N/mm). Since the low tensile strength of concrete materials,
the plain concrete was failed once the crack occurred and suddenly
developed, thus received low fracture energy. However, after
initiation of the crack, the pull-out and rupture processes of
randomly distributed PP fibers in the concrete matrix consumed a
considerable volume of energy, thus significantly improving the
fracture energy of plain concrete. Additionally, even if the flexural
strength was reduced with the added rubber aggregates and the
reduction was increased with the increasing of rubber content in
PP-fiber reinforced rubber concrete samples, the fracture energy of
that was furtherly improved with the addition of rubber aggregates.
Fig. 10. Observation of failure modes in different types of sample: a) Failure mode of
sample in “CO” group; b) Failure mode of sample in “FR-10” group; c) Observation of
crack formation of sample in “CO” group; d) Observation of crack formation of sample
in “PP” group; e) Observation of crack formation of sample in “FR-10” group.
CO PP FR-10 FR-15
0.0
1.5
3.0
4.5
6.0
7.5
28
days
flexural
strength
(Mpa)
Sample types
28 days flexural strength
Fig. 11. Flexural strength of different specimens.
0.133
2.03
2.17
2.27
CO
PP
FR-10
FR-15
0.0 0.5 1.0 1.5 2.0 2.5
Fracture energy (N/mm)
s
n
e
m
i
c
e
p
S
Fracture energy
Fig. 12. Computed fracture energy of different sample types.
1358

Comparing that of specimens in “PP” group, which was enhanced
about 0.14 N/mm and 0.24 N/mm in the specimens of “FR-10” and
“FR-15” groups, respectively. From the previous study, the fracture
energy of rubberized concrete with different rubber contents is in a
rough range from 0.1 N/mm to 0.3 N/mm (Reda Taha et al., 2008b;
Sukontasukkul and Chaikaew, 2006), while the fracture energy of
plain concrete is 0.13 N/mm as shown in this study. Therefore, the
rubbers only have a slight effect on the post-fracture behaviors in
concrete. However, the combination of macro PP fiber with rubber
aggregates furtherly enlarged the positive effect of rubbers as
shown in the aforementioned enhancement in “FR-10” and “FR-15”
samples. This outcome proved the observations of the splitting
tensile failure patterns and the flexural post-crack behaviors in the
previous sections.
3.2.4. SEM image of fracture surface
As shown in Fig. 13a), the cement matrix in the vicinity area of
the rubber particle presented dense structure, which indicated that
the addition of treated rubber aggregate can enhance the interfacial
transition zone (ITZ) between the rubber and cement matrix (Najim
and Hall, 2013). In the meanwhile, as shown in Fig.13b), the cement
hydration products were observed on the surface of the rubber
particle in front of a fiber bundle, which demonstrated that the
absorbed sodium on rubber surface reacted with cement after
NaOH solution treatment. On top of that, the effect of rubbers on
the crack propagation resistance was also discovered. The width of
the micro-crack was reduced towards the rubber surface as shown
in Fig.13c), and once the crack tip touched the rubber, the stress can
be released by the low stiffness rubber and then the crack propa-
gated along with the interface between cement matrix and rubber
particle as observed in Fig. 13d). Besides the macro PP fiber-
bridging effect on the macro-cracks, the added rubber particle
can provide crack propagation resistance after the initiation of
micro-cracks in the cement matrix. The entire post-crack propa-
gation process could be synergistically benefitted with hybridizing
of rubber aggregate and macro PP fiber.
3.2.5. Ultrasonic pulse velocity (UPV)
The test results were summarized as shown in Fig. 14. It is
obviously to find that the pulse transmission speed was slightly
decreased with the introduction of PP fibers and more scrap tire
rubber aggregates, which indicated the dynamic modulus of the
Fig. 13. ESEM image observations on fracture surfaces of PP-fiber reinforced rubber concrete: a) The dense structure of cement matrix near the rubber; b) Cement hydration
products on the surfaces of rubber particle; c) Crack propagation path was changed along rubber-cement interface; d) BSE image of cracks formed at interface transition zone as well
as cement-rubber interface.
Control PP FR-10 FR-15
2.0
2.5
3.0
3.5
4.0
4.5
5.0
3.66km/s
Questionable
Excellent
Concrete
Classification
based on UPV
28
days
ultrasonic
pulse
velocity
(UPV)
(km/s)
specimen types
28 days ultrasonic pulse velocity (UPV)
Good
4.57km/s
Fig. 14. 28 days ultrasonic wave transmission speed.

solid structure was reduced. On the one hand, since the elastic
modulus of the PP fiber and rubber are much lower when
compared with hardened cement matrix and conventional fine
aggregates, respectively. On the other hand, the presence of PP fiber
and rubbers entrapped more air voids in the solid slides, which
could also affect the pulse velocity. Therefore, the addition of PP
fibers and rubbers will slightly decrease the dynamic modulus of
the plain concrete, which could benefit the impact resistance of
brittle plain concrete. Additionally, the UPVs of all samples that
prepared in this investigation is in the range between 3.66 km/s to
4.57 km/s, which can illustrate the good quality and consistency of
concrete samples that produced in this investigation (Malhotra,
1976; Solis-Carca~
no et al., 2008).
3.2.6. Bulk electrical resistivity
The test results of bulk electrical resistivity were shown in
Fig. 15. Comparing with control specimens, the bulk electrical re-
sistivity increased about 10.3% and 15.8% with the addition of PP
fibers and combined with 10% rubber aggregates, respectively. On
the one hand, due to the electrical insulation property of both PP
fiber and rubber particles (Kakooei et al., 2012; Mohammed et al.,
2012), the electrical transfer between two measure electrodes can
be blocked. On the other hand, with the impermeable rubber par-
ticles, the pathway of pore solution can be obstructed, which also
contributed to the improvement of the bulk electrical resistivity.
However, after increasing the rubber content to 15%, the porosity
inside the concrete matrix was increased (Onuaguluchi and
Panesar, 2014) with higher rubber content due to reduced work-
ability. Besides, since the size range of rubber aggregate is limited
and the fineness modulus was larger than normal fine aggregate,
which may cause less compacted microstructures. The proper
content of rubber aggregates (15%) and the addition of macro PP-
fiber can increase the bulk electrical resistivity and thus reducing
the transport property.
3.3. Durability performance
3.3.1. Drying shrinkage test
As shown in Fig. 16, with the added rubber particles, the length
change was increased. Due to the decreased stiffness of rubber
aggregate when compared with normal fine aggregates, the rubber
could be easily deformed under the internal drying shrinkage stress
(Sukontasukkul and Tiamlom, 2012). However, since the intro-
duction of macro PP fibers into the rubberized mortar, the drying
shrinkage length change was apparently reduced and became
lower than the control samples, which was decreased 15.5%. The
CO FCO FR-10 FR-15
0
2
4
6
8
10
28
Days
Bulk
electrical
resistivity
(K
-cm)
Specimens
28 Days Bulk electrical resistivity
Fig. 15. The bulk electrical resistivity of concrete specimens.
0 3 6 9 12 15 18 21
-0.12
-0.10
-0.08
-0.06
-0.04
-0.02
0.00
Drying
shrinkage
length
change
(%)
Curing time (days)
COM
ROM
FRM
Fig. 16. The length change rate by drying shrinkage.
1360

added fibers could restrain the mortar matrix and resist the length
change of the mortar bar through its mechanical bonding with
cement paste (Turatsinze et al., 2006; Wang et al., 2019). The
increased drying shrinkage caused by rubber aggregates could be
properly limited with the application of macro-PP fiber
reinforcement.
3.3.2. ASR expansion test
The results in the length change of mortar bars are demon-
strated as shown in Fig. 17. After 14 days, the expansion rate of
mortar bar was reduced with the implement of rubber particles,
because the elastic rubber could release the internal stress that
caused by the generation of ASR gel (Afshinnia and Poursaee, 2015).
In addition, the fiber-reinforcement also contributed to minimizing
the length expansion caused by ASR damage. The fibers could
prevent the expansion of the cement mortar bar through its
bridging effect. Once the cement matrix tended to expand, the fi-
bers could restrain cement matrix and thus reducing the devel-
opment of the expansion (Park and Lee, 2004; Wang et al., 2018).
Consequently, after adding rubber and fibers, the expansion due to
ASR at 14 days was lower than 0.1% as the results presented. Ac-
cording to the ASTM C1260 standard, if the ASR expansion is
smaller than 0.1% at 14 days, the possibility of generating ASR
damage is very low.
3.3.3. Frost resistance test
3.3.3.1. Relative dynamic modulus of elasticity. The relative dynamic
modulus of elasticity at different freeze-thaw cycles is calculated as
shown in Fig. 18 a) based on the measured resonance frequency as
plotted in Fig. 18 b). The dynamic modulus of elasticity was
increased when compared with the initial measurements among all
test groups. The increase in dynamic modulus indicated good
quality and freeze-thaw resistance of concrete specimens produced
in this evaluation. After relative short curing time of 28 days, even if
exposed to the freeze-thaw chamber, the concrete specimens with
good quality could still be kept hydrating (Graybeal, 2006). The
hydration resulted in a denser structure inside the concrete sam-
ples when compared with the initial condition, especially for
specimens in the “FR-10” group, the relative dynamic modulus was
increased about 12% after 300 cycles. Regards to the samples in PP
group, no noticeable change in relative dynamic modulus was
found when compared with control samples, which may indicate
that the addition of macro PP fiber may not have a visible effect on
the freezing and thawing performance of ordinary concrete (Allan
and Kukacka, 1995). From Fig. 18 b), it can also be observed that
the resonance frequency was gradually reduced with the increase
of rubber content, which is consistent with the results of ultrasonic
wave velocity measurement in this investigation. The reduction of
the resonance frequency of concrete samples is attributed to the
relatively lower stiffness of rubber aggregate comparing with that
of conventional fine aggregate. Also, the rubber aggregates can
entrap more air into the concrete samples, which may result in a
higher air voids content in the hardened concrete specimens
(Mohammed et al., 2012).
3.3.3.2. Frost damage durability factor. The durability factor was
then calculated based on the results of relative dynamic modulus
change by following equation (4) based on the ASTM C666
standard.
DF ¼ PN=M (4)
where, DF ¼ durability factor of the test specimen; P ¼ relative dy-
namic modulus of elasticity at N cycles, %; N ¼ number of cycles at
which P reaches the specified minimum value for discontinuing the
test or the specified number of cycles at which the exposure is to be
terminated, whichever is less; and M ¼ specified number of cycles
0 2 4 6 8 10 12 14
0.00
0.05
0.10
Length
expansion
change
(%)
Curing time (days)
COM
ROM
FRM
Suggested limit at 14 days (ASTM C1260)
Fig. 17. The length expansion change by ASR damage.
0 50 100 150 200 250 300
90
100
110
120
130
0 50 100 150 200 250 300
2100
2250
2400
2550
2700
Modulus gain
Relative
dynamic
modulus
of
elasticity
(%)
Freeze-thaw cycle (times)
CO
PP
FR-10
FR-15
Modulus loss
b)
Resonace
frequency
(Hz)
Freeze-thaw cycles (times)
CO
PP
FR-10
FR-15
a)
Fig. 18. The relative dynamic modulus of elasticity versus the freeze-thaw cycles.

at which the exposure is to be terminated.
The calculated average durability factors for different types of
samples are shown in Fig. 19. A higher durability factor indicated
improved freeze-thaw performance (Richardson et al., 2012). The
higher durability factor of specimens in the “FR-10” group could
illustrate that the introduction of low content of fine rubber
aggregate to replace the conventional rubber aggregates could help
to enhance the freeze-thaw resistance (Richardson et al., 2012),
thus achieve a better durability performance in freeze-wet climate.
The increased air content due to the introduction of rubber
aggregate may help to improve the freeze-thaw resistance. In
addition, since the lowest transport property of specimens in the
“FR-10” group, as shown in the bulk electrical resistivity result, the
samples with 10% rubber aggregates may also contribute to the
enhanced freeze-thaw durability factor.
3.3.3.3. Length change. The length of different concrete samples is
measured at each exposure stage. The length change was then
computed based on the initial measurements and the effective gage
length, which are demonstrated in Fig. 20. As the results showed,
no concrete sample expanded during the first 100 cycles. Since the
concrete samples were stored into the freeze-thaw chamber after
only 28 days curing, the autogenous shrinkage may generate by
continuous cement hydration (Gao et al., 2018). At the same time,
during the freeze-in air procedure, the loss of moisture may also
happen and cause drying shrinkage of concrete samples. It is
noticeable that the shrinkage volume in the concrete samples
incorporating with rubber aggregate is larger than that of speci-
mens without the addition of rubber, the soft rubber particles were
easily deformed than conventional fine aggregates as demon-
strated before, but the maximum shrinkage in the FR-10 group was
only 0.068% after 300 cycles. After 150 cycles, the control speci-
mens showed slight expansion behavior as the length of the
specimen was increased based on the initial measurement, and the
expansion tended to increase until 300 cycles, which indicated that
the internal freeze pressure had caused expansion of control con-
crete specimens. Nevertheless, the modified concrete samples with
PP fiber or rubber aggregates did not show length expansion. The
presence of rubber aggregate could effectively provide frost pro-
tection by releasing the internal stress due to freeze expansion of
the pore solution.
4. Conclusions
During this study, the mechanical, microstructural and dura-
bility properties of the macro PP fiber-reinforced rubber concrete
were evaluated, and the synergetic effect by combining macro PP
fiber and treated rubber aggregate in concrete is verified. The
conclusions can be summarized below:
1. After introducing rubber aggregates into macro PP fiber-
reinforced concrete, the strength was reduced with the
increasing of rubber content as expected. However, with hy-
bridizing of macro PP fiber and treated rubber aggregates, the
post-fracture behavior of macro PP fiber reinforced rubber
concrete samples were significantly improved with increased
residual load capacity and deformation. The total fracture en-
ergy release rate of macro PP fiber reinforced rubber concrete
samples was improved when compared with plain concrete,
where fracture energy was furtherly increased with a higher
rubber content. The brittle failure of plain concrete was reduced
with the development of multiple post-failure cracks through
rubber particle-cement interface behavior and the enlarged
crack open deformation due to the PP fiber’s crack-bridging
effects.
2. Regards to the durability performance, the bulk electrical re-
sistivity of samples in “FR-10” group achieved the highest value
among all types of samples, which indicated the cooperation of
0.5% macro PP fiber and 10% treated rubber aggregate replace-
ment represented the lowest transport property. The relatively
large drying shrinkage of rubberized mortar samples could be
restrained with the added macro PP fiber. The length change of
mortar bars by the alkali-silica reaction can also be controlled by
combining rubber aggregate and macro PP fiber. The introduc-
tion of 10% rubber aggregates and macro PP fiber also repre-
sented the best freeze-thaw resistance among all sample types,
which is attributed to the lowest transport property as conclude
in the bulk electrical resistivity test.
In summary, the evaluation of macro PP fiber reinforced
rubberized concrete showed the synergy effect by hybridizing
macro PP fiber and rubber aggregates in concrete material. It could
become a cost-effective, environmental-friendly, and durable ma-
terial for civil construction.
CO PP FR-10 FR-15
0
25
50
75
100
125
103.6
111.8
104.1
Durability
factor
Sample types
Durability factor
103.5
Fig. 19. The durability factor of different types samples.
0 50 100 150 200 250 300
-0.20
-0.16
-0.12
-0.08
-0.04
0.00
0.04
0.08
0.12
Shrinkage
Length
change
in
percent
(%)
Freeze-thaw cycles (times)
CO
PP
FR-10
FR-15
Expansion
Fig. 20. The length change of different concrete samples during the freeze-thaw cycles.
1362

Acknowledgement
The authors would like to acknowledge the funding support of
this research work from the Michigan Department of Environ-
mental Quality (MDEQ) under grant No. CU-1631059.
References
ASTM C33/C33M-18, 2018. Standard Specification for Concrete Aggregates. ASTM
International, West Conshohocken, PA. www.astm.org.
ASTM C39/C39M-18, 2018. Standard Test Method for Compressive Strength of Cy-
lindrical Concrete Specimens. ASTM International, West Conshohocken, PA.
www.astm.org.
ASTM C128-15, 2015. Standard Test Method for Relative Density (Specific Gravity)
and Absorption of Fine Aggregate. ASTM International, West Conshohocken, PA.
www.astm.org.
ASTM C150/C150M-17, 2017. Standard Specification for Portland Cement. ASTM
International, West Conshohocken, PA. www.astm.org.
ASTM C157/C157M-17, 2017. Standard Test Method for Length Change of Hardened
Hydraulic-Cement Mortar and Concrete. ASTM International, West Con-
shohocken, PA. www.astm.org.
ASTM C666/C666M-15, 2015. Standard Test Method for Resistance of Concrete to
Rapid Freezing and Thawing. ASTM International, West Conshohocken, PA.
www.astm.org.
ASTM C1260-14, 2014. Standard Test Method for Potential Alkali Reactivity of Ag-
gregates (Mortar-Bar Method). ASTM International, West Conshohocken, PA.
www.astm.org.
363, A.C, 2010. Report on High-Strength Concrete. ACI. ACI 363R-10.
ACI, 2009. State-of-the-Art Report on Fiber Reinforced Concrete-ACI 544.1 R-96
(Reapproved 2009), vol. 6, p. 4.
Afshinnia, K., Poursaee, A., 2015. The influence of waste crumb rubber in reducing
the alkaliesilica reaction in mortar bars. J. Build Eng. 4, 231e236.
Ahmed Dabbak, S., Illias, H., Ang, B., Abdul Latiff, N., Makmud, M., 2018. Electrical
properties of polyethylene/polypropylene compounds for high-voltage insu-
lation. Energies 11 (6), 1448.
Albano, C., Camacho, N., Reyes, J., Feliu, J., Hern
andez, M., 2005. Influence of scrap
rubber addition to Portland I concrete composites: destructive and non-
destructive testing. Compos. Struct. 71 (3e4), 439e446.
Alhozaimy, A., Soroushian, P., Mirza, F., 1996. Mechanical properties of poly-
propylene fiber reinforced concrete and the effects of pozzolanic materials.
Cement Concr. Compos. 18 (2), 85e92.
Allan, M., Kukacka, L., 1995. Strength and durability of polypropylene fibre rein-
forced grouts. Cement Concr. Res. 25 (3), 511e521.
Association, U.S.T.M., 2018. 2017 U.S Scrap Tire Management Summary, p. 5.
ASTM, 2015. ASTM C143/C143M-15a, Standard Test Method for Slump of Hydraulic-
Cement Concrete. ASTM International, West Conshohocken, PA, 2015. www.
astm.org.
ASTM, 2017a. ASTM C138/C138M-17a, Standard Test Method for Density (Unit
Weight), Yield, and Air Content (Gravimetric) of Concrete. ASTM International,
West Conshohocken, PA, 2017. www.astm.org.
ASTM, 2017b. ASTM C231/C231M-17a, Standard Test Method for Air Content of
Freshly Mixed Concrete by the Pressure Method. ASTM International, West
Conshohocken, PA, 2017. www.astm.org.
ASTM, 2017c. ASTM C496/C496M-17, Standard Test Method for Splitting Tensile
Strength of Cylindrical Concrete Specimens. ASTM International, West Con-
shohocken, PA, 2017. www.astm.org.
Banthia, N., Gupta, R., 2006. Influence of polypropylene fiber geometry on plastic
shrinkage cracking in concrete. Cement Concr. Res. 36 (7), 1263e1267.
Banthia, N., Soleimani, S.M., 2005. Flexural response of hybrid fiber-reinforced
cementitious composites. ACI Mater. J. 102 (6), 382.
Bayasi, Z., Zeng, J., 1993. Properties of polypropylene fiber reinforced concrete.
Mater. J. 90 (6), 605e610.
Dong, Q., Huang, B., Shu, X.J.C., Materials, B., 2013. Rubber Modified Concrete
Improved by Chemically Active Coating and Silane Coupling Agent, vol. 48,
pp. 116e123.
Eldin, N.N., Piekarski, J.A., 1993. Scrap tires: management and economics. J. Environ.
Eng. 119 (6), 1217e1232.
Eldin, N.N., Senouci, A.B., 1993. Rubber-tire particles as concrete aggregate. J. Mater.
Civ. Eng. 5 (4), 478e496.
Fraternali, F., Ciancia, V., Chechile, R., Rizzano, G., Feo, L., Incarnato, L.J.C.S., 2011.
Experimental study of the thermo-mechanical properties of recycled. PET Fiber
Reinf. Concr. 93 (9), 2368e2374.
Ganjian, E., Khorami, M., Maghsoudi, A.A., 2009. Scrap-tyre-rubber replacement for
aggregate and filler in concrete. Constr. Build. Mater. 23 (5), 1828e1836.
Gao, Y., Corr, D.J., Konsta-Gdoutos, M.S., Shah, S.P., 2018. Effect of carbon nanofibers
on autogenous shrinkage and shrinkage cracking of cementitious nano-
composites. ACI Mater. J. 115 (4).
Gettu, R., Gardner, D., Saldivar, H., Barrag
an, B., 2005. Study of the distribution and
orientation of fibers in SFRC specimens. Mater. Struct. 38 (1), 31e37.
Graybeal, B.A., 2006. Material Property Characterization of Ultra-high Performance
Concrete.
Grzybowski, M., Shah, S.P., 1990. Shrinkage cracking of fiber reinforced concrete. ACI
Mater. J. 87 (2), 138e148.
Guo, S., Dai, Q., Si, R., Sun, X., Lu, C., 2017. Evaluation of properties and performance
of rubber-modified concrete for recycling of waste scrap tire. J. Clean. Prod. 148,
681e689.
Guo, S., Dai, Q., Sun, X., Sun, Y., 2016. Ultrasonic scattering measurement of air void
size distribution in hardened concrete samples. Constr. Build. Mater. 113,
415e422.
Ho, A.C., Turatsinze, A., Hameed, R., Vu, D.C., 2012. Effects of rubber aggregates from
grinded used tyres on the concrete resistance to cracking. J. Clean. Prod. 23 (1),
209e215.
Hsie, M., Tu, C., Song, P., 2008a. Mechanical properties of polypropylene hybrid
fiber-reinforced concrete. Mater. Sci. Eng. A 494 (1e2), 153e157.
Hsie, M., Tu, C., Song, P.J.M.S., A, E, 2008b. Mechanical Properties of Polypropylene
Hybrid Fiber-Reinforced Concrete, vol. 494, pp. 153e157, 1-2.
Kakooei, S., Akil, H.M., Jamshidi, M., Rouhi, J., 2012. The effects of polypropylene
fibers on the properties of reinforced concrete structures. Constr. Build. Mater.
27 (1), 73e77.
Khaloo, A.R., Dehestani, M., Rahmatabadi, P., 2008. Mechanical properties of con-
crete containing a high volume of tireerubber particles. Waste Manag. 28 (12),
2472e2482.
Khatib, Z.K., Bayomy, F.M., 1999. Rubberized Portland cement concrete. J. Mater. Civ.
Eng. 11 (3), 206e213.
Khorrami, M., Khalilitabas, A.A., Desai, C.S., Ardakani, M.M., 2010. Experimental
investigation on mechanical characteristics and environmental effects on rub-
ber concrete. Int. J. Concr. Struct. Mater. 4 (1), 17e23.
Kim, S.B., Yi, N.H., Kim, H.Y., Kim, J.-H.J., Song, Y.-C., 2010. Material and structural
performance evaluation of recycled PET fiber reinforced concrete. Cement
Concr. Compos. 32 (3), 232e240.
Kotresh, K., Belachew, M.G., 2014. Study on waste tyre rubber as concrete aggre-
gates. Int. J. Sci. Eng. Technol. 3 (4), 433e436.
Layssi, H., Ghods, P., Alizadeh, A.R., Salehi, M., 2015. Electrical resistivity of concrete.
Concr. Int. 37 (5), 41e46.
Libre, N.A., Shekarchi, M., Mahoutian, M., Soroushian, P., 2011. Mechanical proper-
ties of hybrid fiber reinforced lightweight aggregate concrete made with nat-
ural pumice. Constr. Build. Mater. 25 (5), 2458e2464.
Malhotra, V.M., 1976. Testing Hardened Concrete: Nondestructive Methods. Iowa
State Press.
Meddah, A., Beddar, M., Bali, A., 2014a. Use of shredded rubber tire aggregates for
roller compacted concrete pavement. J. Clean. Prod. 72, 187e192.
Meddah, A., Beddar, M., Bali, A., 2014b. Use of Shredded Rubber Tire Aggregates for
Roller Compacted Concrete Pavement, vol. 72, 187e192.
Mohammadi, I., Khabbaz, H., Vessalas, K.J.C., Materials, B., 2014. In-depth Assess-
ment of Crumb Rubber Concrete (CRC) Prepared by Water-Soaking Treatment
Method for Rigid Pavements, vol. 71, pp. 456e471.
Mohammed, B.S., Hossain, K.M.A., Swee, J.T.E., Wong, G., Abdullahi, M., 2012.
Properties of crumb rubber hollow concrete block. J. Clean. Prod. 23 (1), 57e67.
Mohod, M.V., 2015. Performance of polypropylene fibre reinforced concrete. IOSR J.
Mech. Civ. Eng. 12 (1), 28e36.
Najim, K.B., Hall, M.R., 2013. Crumb rubber aggregate coatings/pre-treatments and
their effects on interfacial bonding, air entrapment and fracture toughness in
self-compacting rubberised concrete (SCRC). Mater. Struct. 46 (12), 2029e2043.
Ochi, T., Okubo, S., Fukui, K.J.C., Composites, C., 2007. Development of Recycled PET
Fiber and its Application as Concrete-Reinforcing Fiber, vol. 29, pp. 448e455, 6.
Onuaguluchi, O., Panesar, D., 2014. Hardened properties of concrete mixtures
containing pre-coated crumb rubber and silica fume. J. Clean. Prod. 82, 125e131.
Park, S.-B., Lee, B.-C.J.C., 2004. Studies on expansion properties in mortar containing
waste glass and fibers. Cement Concr. Res. 34 (7), 1145e1152.
Pelisser, F., Zavarise, N., Longo, T.A., Bernardin, A.M., 2011. Concrete Made with
Recycled Tire Rubber: Effect of Alkaline Activation and Silica Fume Addition, vol.
19, 757e763, 6-7.
Presti, D.L., 2013. Recycled tyre rubber modified bitumens for road asphalt mix-
tures: a literature review. Constr. Build. Mater. 49, 863e881.
Reda Taha, M.M., El-Dieb, A., Abd El-Wahab, M., Abdel-Hameed, M., 2008a. Me-
chanical, fracture, and microstructural investigations of rubber concrete.
J. Mater. Civ. Eng. 20 (10), 640e649.
Reda Taha, M.M., El-Dieb, A., Abd El-Wahab, M., Abdel-Hameed, M., 2008b. Me-
chanical, Fracture, and Microstructural Investigations of Rubber Concrete, vol.
20, 640e649, 10.
Richardson, A.E., Coventry, K.A., Ward, G., 2012. Freeze/thaw protection of concrete
with optimum rubber crumb content. J. Clean. Prod. 23 (1), 96e103.
Segre, N., Joekes, I., 2000. Use of tire rubber particles as addition to cement paste.
Cement Concr. Res. 30 (9), 1421e1425.
Shen, L., Worrell, E., Patel, M.K.J.R., 2010. Open-loop recycling: a LCA case study of
PET bottle-to-fibre recycling. Conserv. Recycl. 55 (1), 34e52.
Si, R., Wang, J., Guo, S., Dai, Q., Han, S., 2018. Evaluation of laboratory performance of
self-consolidating concrete with recycled tire rubber. J. Clean. Prod. 180,
823e831.
Siddique, R., Naik, T.R., 2004. Properties of concrete containing scrap-tire rubberean
overview. Waste Manag. 24 (6), 563e569.
Solis-Carca~
no, R., Moreno, E.I.J.C., Materials, B., 2008. Evaluation of Concrete Made
with Crushed Limestone Aggregate Based on Ultrasonic Pulse Velocity, vol. 22,
pp. 1225e1231, 6.
Standard, J., 2003. Method of Test for Load-Displacement Curve of Fiber Reinforced
Concrete by Use of Notched Beam, JCI-S-002-2003. Japan Concrete Institute
(JCI).

Sukontasukkul, P., Chaikaew, C., 2006. Properties of concrete pedestrian block
mixed with crumb rubber. Constr. Build. Mater. 20 (7), 450e457.
Sukontasukkul, P., Tiamlom, K., 2012. Expansion under water and drying shrinkage
of rubberized concrete mixed with crumb rubber with different size. Constr.
Build. Mater. 29, 520e526.
Sunthonpagasit, N., Duffey, M.R.J.R., 2004. Scrap tires to crumb rubber: feasibility
analysis for processing facilities. Conserv. Recycl. 40 (4), 281e299.
Turatsinze, A., Granju, J.-L., Bonnet, S., 2006. Positive synergy between steel-fibres
and rubber aggregates: effect on the resistance of cement-based mortars to
shrinkage cracking. Cement Concr. Res. 36 (9), 1692e1697.
Wang, J., Dai, Q., Guo, S., Si, R., 2019. Study on rubberized concrete reinforced with
different fibers. ACI Mater. J. 116 (2).
Wang, J., Dai, Q., Si, R., Guo, S., 2018. Investigation of properties and performances of
Polyvinyl Alcohol (PVA) fiber-reinforced rubber concrete. Constr. Build. Mater.
193, 631e642.
Yin, S., Tuladhar, R., Shi, F., Combe, M., Collister, T., Sivakugan, N.J.C., Materials, B.,
2015. Use of Macro Plastic Fibres in Concrete: a Review, vol. 93, pp. 180e188.
You, L., You, Z., Dai, Q., Xie, X., Washko, S., Gao, J.J.C., Materials, B., 2019. Investi-
gation of Adhesion and Interface Bond Strength for Pavements Underlying
Chip-Seal: Effect of Asphalt-Aggregate Combinations and Freeze-Thaw Cycles
on Chip-Seal, vol. 203, pp. 322e330.
Yung, W.H., Yung, L.C., Hua, L.H., 2013. A study of the durability properties of waste
tire rubber applied to self-compacting concrete. Constr. Build. Mater. 41,
665e672.
Zollo, R.F., 1997. Fiber-reinforced concrete: an overview after 30 years of develop-
ment. Cement Concr. Compos. 19 (2), 107e122.
1364

DURABILIDAD.pdf

Recommended

Recommended

More Related Content

Similar to DURABILIDAD.pdf

Similar to DURABILIDAD.pdf (20)

Recently uploaded

Recently uploaded (20)

DURABILIDAD.pdf