may guide many benefits such as reducing the demolition
landfills and the use of the natural resources, it may affect the
quality of the concrete. Additionally, many studies have
been conducted on the use of CWD as Recycled Aggregate
(RA) in concrete. Although using RA may guide many
benefits such as reducing the demolition landfills and the use
of natural resources, it may affect the quality of the concrete.
For example, it has been demonstrated that 100% usage of
RA may only cause a reduction of 10, 17, and 21% to the
compressive strength, the tensile strength and the elastic
modulus of concrete, respectively (Agrela et al. 2013).
However, the resource of the used RA has been shown to
have an important role in evaluating the recycled concrete
properties. In this study, the RA produced in the UAE will
be utilized.
On the other hand, CW has been applied partially in the
concrete as coarse aggregate, fine aggregate, and cement.
For example, Kannan et al. (2017) show that 40% partial
replacement of cement by Ceramic Waste Powder
(CWP) can obtain concrete of superior durability, low
chloride ion permeability, and high electrical resistivity
although 15% decrease in the compressive strength was
observed. Another example by Siddique et al. (2018) displays that 40% replacement of Natural Fine Aggregate
(NFA) by CW can increase the compressive strength and the
split tensile strength of concrete by 16% and 7%,
respectively.
However, it is rare to find that there is a research in which
RA and CW are combined in the same concrete mix.
Moreover, none of the previous research uses 100% of the
RA together with CW. This shows the originality of this
study which utilizes 100% RA and 20% of CW in the
concrete mix to check the effect of this utilization on the
mechanical properties and the cost of the new mixes.
2 Experimental Procedure
2.1 Materials
Figure 1 explores the materials used in the mixes. The
properties of these materials are given below:
Cement. The cement used to prepare all the mixes is
Type I Ordinary Portland Cement. The cement is produced
in the United Arab Emirates by UltraTech Cement Factory.
The cement conforms the BS EN 197-1:2011 standard with
class 42.5 N. The letter N represents that the cement has a
normal setting rate.
Natural Coarse Aggregate (NCA). Two types of coarse
aggregates are used in this research: 10 and 20 mm with a
combined ratio of 1:4. Using ASTM standards (Kett 2010),
the properties of the aggregates are determined by performing various tests including, sieve analysis, specific
gravity, Rodded Unit Weight, and moisture content. Table 1
demonstrates these properties.
Natural Fine Aggregate (NFA). Black sand is used as
NFA in the concrete mix. All the required data including,
sieve analysis, specific gravity, fineness modulus, and
moisture content are obtained by performing standard tests
(Kett 2010) as seen in Table 1. It is important to note that the
fineness modulus is 3.27, which is more than 3 as a result of
coarse sand.
Recycled Coarse Aggregate (RCA). The RCA used in
this research is obtained from Bee’ah recycling plant located
in Sharjah, UAE. The maximum diameter size of the recycled aggregates is 14 mm. Table 1 shows the properties of
the RCA where it can be seen that the moisture content and
the water absorption for the RCA are higher than the NCA
due to the fully or partially mortar layer still attached to the
RCA.
Recycled Ceramic Waste. The ceramic waste to partially
replace fine aggregates is obtained by crushing the waste
tiles. The tiles are crushed using the Los Angeles Abrasion
Machine in the Geoscience Testing Laboratory, Jebel Ali,
Dubai. The crushed material is further sieved to obtain the
required size from 5 to 0.15 mm as Ceramic Fine Aggregate
(CFA). Table 1 shows that CFA has lower specific gravity
and fineness modulus, but much higher in terms of the water
absorption and the moisture content. For partial replacement
of cement, Ceramic Waste Powder (CWP) from the polishing of the ceramic tiles was utilized.
Superplasticizer. The superplasticizer used in the mix is
PC 400. It is based on polycarboxylate (PC) ether. PC 400
has many advantages including, increases the early strength
development, reduces permeability, helps to resist frost and
carbonation, increases the workability, reduces drying
shrinkage (PAC Technologies LLC 2018). PC 400 is added
to the mixture during the mixing process after 80% of the
water has been added. The dosage of the PC 400 is 0.8–1.5%
of cement. The amount of superplasticizer used in this study
is 1.25% to the weight of cement.
2.2 Mix Proportioning
The concrete mixes were designed using ASTM standard
(Kett 2010) for M40 concrete grade in which the characteristic cylindrical compressive strength (f ck ) is 40 MPa with
mean cylindrical strength (f cr ) of 49.6 MPa (Kett 2010). Mix
codes together with a description of each mix are shown in
Table 2. Also, Table 3 demonstrates the materials’ quantity
per m
3 of concrete.
150
S. T. M. Ali and M. Batikha
landfills and the use of the natural resources, it may affect the
quality of the concrete. Additionally, many studies have
been conducted on the use of CWD as Recycled Aggregate
(RA) in concrete. Although using RA may guide many
benefits such as reducing the demolition landfills and the use
of natural resources, it may affect the quality of the concrete.
For example, it has been demonstrated that 100% usage of
RA may only cause a reduction of 10, 17, and 21% to the
compressive strength, the tensile strength and the elastic
modulus of concrete, respectively (Agrela et al. 2013).
However, the resource of the used RA has been shown to
have an important role in evaluating the recycled concrete
properties. In this study, the RA produced in the UAE will
be utilized.
On the other hand, CW has been applied partially in the
concrete as coarse aggregate, fine aggregate, and cement.
For example, Kannan et al. (2017) show that 40% partial
replacement of cement by Ceramic Waste Powder
(CWP) can obtain concrete of superior durability, low
chloride ion permeability, and high electrical resistivity
although 15% decrease in the compressive strength was
observed. Another example by Siddique et al. (2018) displays that 40% replacement of Natural Fine Aggregate
(NFA) by CW can increase the compressive strength and the
split tensile strength of concrete by 16% and 7%,
respectively.
However, it is rare to find that there is a research in which
RA and CW are combined in the same concrete mix.
Moreover, none of the previous research uses 100% of the
RA together with CW. This shows the originality of this
study which utilizes 100% RA and 20% of CW in the
concrete mix to check the effect of this utilization on the
mechanical properties and the cost of the new mixes.
2 Experimental Procedure
2.1 Materials
Figure 1 explores the materials used in the mixes. The
properties of these materials are given below:
Cement. The cement used to prepare all the mixes is
Type I Ordinary Portland Cement. The cement is produced
in the United Arab Emirates by UltraTech Cement Factory.
The cement conforms the BS EN 197-1:2011 standard with
class 42.5 N. The letter N represents that the cement has a
normal setting rate.
Natural Coarse Aggregate (NCA). Two types of coarse
aggregates are used in this research: 10 and 20 mm with a
combined ratio of 1:4. Using ASTM standards (Kett 2010),
the properties of the aggregates are determined by performing various tests including, sieve analysis, specific
gravity, Rodded Unit Weight, and moisture content. Table 1
demonstrates these properties.
Natural Fine Aggregate (NFA). Black sand is used as
NFA in the concrete mix. All the required data including,
sieve analysis, specific gravity, fineness modulus, and
moisture content are obtained by performing standard tests
(Kett 2010) as seen in Table 1. It is important to note that the
fineness modulus is 3.27, which is more than 3 as a result of
coarse sand.
Recycled Coarse Aggregate (RCA). The RCA used in
this research is obtained from Bee’ah recycling plant located
in Sharjah, UAE. The maximum diameter size of the recycled aggregates is 14 mm. Table 1 shows the properties of
the RCA where it can be seen that the moisture content and
the water absorption for the RCA are higher than the NCA
due to the fully or partially mortar layer still attached to the
RCA.
Recycled Ceramic Waste. The ceramic waste to partially
replace fine aggregates is obtained by crushing the waste
tiles. The tiles are crushed using the Los Angeles Abrasion
Machine in the Geoscience Testing Laboratory, Jebel Ali,
Dubai. The crushed material is further sieved to obtain the
required size from 5 to 0.15 mm as Ceramic Fine Aggregate
(CFA). Table 1 shows that CFA has lower specific gravity
and fineness modulus, but much higher in terms of the water
absorption and the moisture content. For partial replacement
of cement, Ceramic Waste Powder (CWP) from the polishing of the ceramic tiles was utilized.
Superplasticizer. The superplasticizer used in the mix is
PC 400. It is based on polycarboxylate (PC) ether. PC 400
has many advantages including, increases the early strength
development, reduces permeability, helps to resist frost and
carbonation, increases the workability, reduces drying
shrinkage (PAC Technologies LLC 2018). PC 400 is added
to the mixture during the mixing process after 80% of the
water has been added. The dosage of the PC 400 is 0.8–1.5%
of cement. The amount of superplasticizer used in this study
is 1.25% to the weight of cement.
2.2 Mix Proportioning
The concrete mixes were designed using ASTM standard
(Kett 2010) for M40 concrete grade in which the characteristic cylindrical compressive strength (f ck ) is 40 MPa with
mean cylindrical strength (f cr ) of 49.6 MPa (Kett 2010). Mix
codes together with a description of each mix are shown in
Table 2. Also, Table 3 demonstrates the materials’ quantity
per m
3 of concrete.
150
S. T. M. Ali and M. Batikha