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UTILIZATION OF RECYCLED AND WASTE MATERIALS IN VARIOUS CONSTRUCTION APPLICATIONS

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More production equals more waste, more waste creates environmental concerns of toxic threat. An economical viable solution to this problem should include utilization of waste materials for new products which in turn minimize the heavy burden on the nation's landfills. Recycling of waste construction materials saves natural resources, saves energy, reduces solid waste, reduces air and water pollutants and reduces greenhouse gases. The construction industry can start being aware of and take advantage of the benefits of using waste and recycled materials. Studies have investigated the use of acceptable waste, recycled and reusable materials and methods. The use of swine manure, animal fat, silica fume, roofing shingles, empty palm fruit bunch, citrus peels, cement kiln dust, fly ash, foundry sand, slag, glass, plastic, carpet, tire scraps, asphalt pavement and concrete aggregate in construction is becoming increasingly popular due to the shortage and increasing cost of raw materials. In this study a questionnaire survey targeting experts from construction industry was conducted in order to investigate the current practices of the uses of waste and recycled materials in the construction industry. This study presents an initial understanding of the current strengths and weaknesses of the practice intended to support construction industry in developing effective policies regarding uses of waste and recycled materials as construction materials.
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American Journal of Environmental Science, 9 (1): 14-24, 2013
ISSN: 1553-345X
©2013 Science Publication
doi:10.3844/ajessp.2013.14.24 Published Online 9 (1) 2013 (http://www.thescipub.com/ajes.toc)
Corresponding Author: Taher Abu-Lebdeh, Department of Civil, Architectural and Environmental Engineering,
North Carolina A and T State University, Greensboro, 27411, North Carolina, United States
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UTILIZATION OF RECYCLED AND WASTE
MATERIALS IN VARIOUS CONSTRUCTION APPLICATIONS
Johnny Bolden, Taher Abu-Lebdeh and Ellie Fini
Department of Civil, Architectural and Environmental Engineering,
North Carolina A and T State University, Greensboro, 27411, North Carolina, United States
Received 2012-12-29, Revised 2013-01-04; Accepted 2013-02-15
ABSTRACT
More production equals more waste, more waste creates environmental concerns of toxic threat. An
economical viable solution to this problem should include utilization of waste materials for new products
which in turn minimize the heavy burden on the nation’s landfills. Recycling of waste construction
materials saves natural resources, saves energy, reduces solid waste, reduces air and water pollutants and
reduces greenhouse gases. The construction industry can start being aware of and take advantage of the
benefits of using waste and recycled materials. Studies have investigated the use of acceptable waste, recycled
and reusable materials and methods. The use of swine manure, animal fat, silica fume, roofing shingles, empty
palm fruit bunch, citrus peels, cement kiln dust, fly ash, foundry sand, slag, glass, plastic, carpet, tire scraps,
asphalt pavement and concrete aggregate in construction is becoming increasingly popular due to the shortage
and increasing cost of raw materials. In this study a questionnaire survey targeting experts from construction
industry was conducted in order to investigate the current practices of the uses of waste and recycled materials
in the construction industry. This study presents an initial understanding of the current strengths and
weaknesses of the practice intended to support construction industry in developing effective policies regarding
uses of waste and recycled materials as construction materials.
Keywords: Recycled Materials, Construction Materials, Environmental Concerns, Natural Resources
1. INTRODUCTION
Several issues exist regarding reducing waste. A key
environmental issue is waste incinerators, furnaces for
burning trash, garbage and ashes. These incinerators
produce 210 different dioxin compounds plus mercury,
cadmium, nitrous oxide, hydrogen chloride, sulfuric acid
and fluorides. Produced also in incinerators is
particulate matter that is small enough to remain
permanently in the lungs. Additionally, waste
incinerators generate more CO
2
emissions than coal, oil,
or natural gas-fueled power plants. For years, scientists
and researchers have been searching for possible
solutions to environmental concerns of waste production
and pollution. Many have found that replacing raw
materials with recycled materials reduces our
dependency on raw materials in the construction
industry. The Federal Highway Administration (FHWA)
estimated that building demolition in the United States
alone produces 123 million tons of construction waste
per year (FHWA, 2004). Begum et al. (2010) supports
the adoption of prefabrication and Industrialized
Building Systems (IBS) to reduce waste generation and
management problems. Their study revealed that a
significant amount of material wastage can be reduced
by the adoption of prefabrication and the rates of reused
and recycled waste materials are relatively higher in
projects that adopt prefabrication. In addition to a
reduction of construction waste generation, Hassim
(2009) identified and discussed other advantages of
applying prefabrication in the building and construction
activities. This include enhance integrity on the building
design and construction, reduction unskilled workers,
reduce construction cost, fixed design at the early stage
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of design, better supervision, promote safer and more
organized construction site and improve environmental
performance through waste minimization. Further, from
the results of the survey, one issue companies felt need
addressing is the creation of a separation process on site
oppose to an accumulation of all waste in one pile. A
solution to this problem would be planning recycling into
the pre construction plans in advance. Integrated Solid
Waste Management (ISWM) is the selection and
application of suitable techniques, technologies
management programs to achieve specific waste
management objectives and goals. Malakahmad et al.
(2010) and his colleagues suggested the
implementation of ISWM systems as a toll for
sustainable development. They concluded that one key
element of ISWM is solid waste separation, which
contributes to a successful recycling program.
Several researchers from NC A&T State
University James et al. (2011); Ellie et al. (2011); Abu-
Lebdeh et al. (2010a; 2010b); Fini and Abu-Lebdeh
(2011) and Hamoush et al. (2011) and other governmental
and academia agencies investigated several green
materials technologies that reduce environmental effects
and use recycled materials in infrastructures applications.
The researchers developed several green material
technology programs, which maintain or improve current
practices in construction engineering and ensures green
products or methods arising from these programs would
be cost effective and would confer benefits on society,
the economy and the environment. In order to obtain
knowledge of the most advanced use of waste and
recycled materials, the author reviewed these and other
studies. For instance, James et al. (2011) researched the
potential use of Recycled Concrete Aggregate (RCA)
and Fly Ash (FA) in concrete pavement. The recycled
concrete came from a demolished local site. Their
research revealed that using RCA up to 25% and FA up
to 15% will not have a significant difference (if any) in
strength compared with concrete containing virgin
aggregate. Thus, using RCA and FA in concrete
pavement may promote economical and environmental
benefit. Hamoush et al. (2011) investigated a new
improved engineered gladding stone for better
toughness, ductility, durability and thermal resistance. In
their research, the back layer of the stone utilized
recycled crumb rubber, which provides a combined
solution for energy saving and environmental concerns.
The results of adding crumb rubber showed a reduction
in the material unit weight, enhanced ductility and
toughness and improved thermal resistance. The stone’s
properties such as compressive strength, thermal
conductivity, durability, impact resistance and water
absorption were experimentally measured and compared
with natural stone specimens. Kaosol (2010) conducted
research on reusing the water treatment sludge from a
water treatment plant to make hollow concrete blocks.
His objectives were to increase the value of the water
treatment sludge from a water treatment plant and to
make a sustainable and profitable disposal alternative for
the water treatment sludge. Findings showed that the
production of the hollow concrete blocks mixed with
water treatment sludge could be a profitable disposal
alternative in the future.
This study presents results from a questionnaire
survey conducted to find out what recycled and waste
materials are currently being used in the construction
industry and areas were construction related companies
need to be informed more to increase the potential use of
such materials. The focus was on applicable waste and
recycling materials within four sectors, namely,
Composite Waste, Industrial Sector Waste, Municipal
Sector Waste and Transportation Sector Waste. Included
is a comprehensive review of data, information, findings
(including benefits/advantages) and evidences relative to
recycling waste materials and construction applications.
Each sector includes subsections of recyclable materials
in relation to the construction industry. The
Transportation Sector waste that can be used as
beneficial recycled materials including tire rubber,
reclaimed asphalt and recycled concrete aggregate. The
Municipal waste sector contains beneficial materials for
the construction industry including roofing shingles,
glass, plastic and carpet. The Industrial waste sector
contain beneficial materials including Cement Kiln Dust
(CKD), foundry sand, fly ash, silica fume and slag. The
composite waste sector includes swine manure, animal
fat, empty palm fruit bunch, citrus peels and sewage
sludge. Findings suggested the need for better
documentation of the use of recycled materials and that
construction industry need to develop effective policies
regarding the use of waste and recycled materials as
construction materials.
The main objective of this study is to investigate the
effective use of recycled and waste materials in various
construction applications. Goals and objectives include:
(1) Review of studies of Recycled Materials in
construction application; (2) Survey of current practices
of uses of waste and recycled material in construction;
(3) Connecting Researches and industry with an
overview of what recycled materials are available for
different applications and (4) Better Documentations for
green infrastructures benefits
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2. MATERIALS AND METHODS
2.1. Tire Rubber
An estimated number of one billion scrap tires have
been disposed of in huge piles across the United States.
An additional 250 million tires unaccounted for are
discarded yearly (RMA, 2011). Whole tires have been
used in artificial reefs, break waters, dock bumpers, soil
erosion control mats and play ground equipment. Several
studies have shown that tire waste can be successfully
used in concrete, grass turf, asphalt mix, embankments,
stone cladding, flowable fill and clay composite.
2.2. Reclaimed Asphalt Pavement
The transportation sector has used Reclaimed
Asphalt Pavement (RAP) for many years. In 2009, the
amount of RAP used in asphalt pavements was 56.0
million tons and in 2010, 62.1 million tons. RAP is
America’s most recycled and reused material; currently,
RAP is being recycled and reused at a rate over 99%. RAP
is used to backfill pavement edges, rework base and base
course. According to the World Business Council for
Sustainable Development, manufactures around the world
produce more than 25 billion tons of concrete yearly.
2.3. Recycled Concrete Aggregate
The Federal Highway Administration (FHWA)
projected an increase in aggregates to over 2.5 billion
tons per year. Crushed aggregate has been used as base
course or granular base in highway construction. Its
primary function is to increase the load capacity of the
pavement and to distribute the applied load to avoid
damage to the sub grade.
2.4. Roofing Shingles
Each year, the U.S. generates approximately 11
million tons of asphalt roofing shingle scrap
(CalRecycle, 2006). Use of recycled asphalt shingles
(both manufacturer’s waste and tear-offs) increased
from 702,000 tons to 1.10 million tons from 2009 to
2010, which represents a 57% increase. Assuming
conservative asphalt content of 20% for shingles, this
represents 234,000 tons (1.5 million barrels) of asphalt
binder conserved. Roofing shingles are made from a
fiberglass or organic backing, asphalt cement, sand-like
aggregate and mineral fillers such as limestone dolomite
and silica. Beneficial applications include, but not
limited, to Hot Mix Asphalt (HMA), cold patch mix
asphalt, aggregate substitute, base course, mineral filler
and granular base stabilizer. Benefits of using roofing
shingles include Lower disposal costs for shingle scrap
manufactures, reduced cost in the production of HMA,
improved the rutting resistance of the mixtures
considerably, due to a combination of the fibers and harder
asphalt and improved resistance to pavement cracking.
2.5. Glass
Americans generated 11.5 million tons of glass in the
Municipal Solid Waste (MSW) stream in 2010. Glass is
composed of silica or sand and contains some amounts
of limestone and soda ash used to produce uniform quality
and color. According to the Association of Cities and
Regions for Recycling (ACRR), people around the world
send 1.5 million tons of glass to landfills each year. Glass
that ends up in the landfill won’t break down for over a
million years. Glass cullet creates workability problems in
concrete mix and the likely hood of alkali-silica reaction.
Beneficial uses are in the secondary applications, such as in
the manufacture of fiberglass insulation, roadbed aggregate,
driving safety reflective beads and decorative tile.
2.6. Plastic
In 2010, plastic waste generated approximately 31
million tons, representing 12.4% of total Municipal Solid
Waste. Uses of recycled plastic in the construction industry
include plastic strips to add to soil embankments, which has
positive results of increasing the measured strength in
reinforcement of soils. HMA mixture has a higher stability,
reduced pavement deformation; increase fatigue resistance
and provide better adhesion between the asphalt and the
aggregate (Awwad and Shbeeb, 2007). Grinded
polyethylene to provide better coating or attached easily to
the aggregate as the surface area of the polymer increases.
2.7. Carpet
According to Carpet America Recovery Efforts
(CARE) in 2010, carpet waste diverted from landfills
was 338 million pounds, 271 million pounds were
recycled, 3 million pounds used for alternative fuel and
23 million pounds for cement kilns. Old carpet is being
recycled and used in composite lumber (both decking
and sheets), tile backer board, roofing shingles, rail road
ties, automotive parts, carpet cushion and stepping stones. A
study by Wang et al. (2000) proved that by adding fibers to
concrete, both toughness and tensile properties increased.
Other benefits in adding carpet fiber to concrete include
reduction of shrinkage, improved fatigue strength, wear
resistance and durability.
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2.8. Cement Kiln Dust
CKD (byproduct of manufacturing Portland cement)
is fine grained, highly alkaline waste, removed from the
cement kiln exhaust gas by air pollution control devices.
Uses of CKD may include: soil stabilization, waste
treatment, cement replacement and asphalt pavement.
CKD is perfect as soil stabilizer improving soils strength
and minimizing work and cost. Siddique (2006)
concluded that concrete mixtures containing low
percentages (5%) of CKD can achieve almost equal
compressive strength, flexural strength, toughness and
freezing and thawing resistance as that of the control
mixture. CKD is a quality adsorbent and natural alkaline
that makes it an effective waste treatment. Emery (1981)
suggested that CKD (mixed with asphalt as mineral filler)
can significantly reduce asphalt cement requirements
between 15 and 25% by volume. CKD added to asphalt
binder produces low ductile mastic asphalt and provides
stripping resistance for the pavement.
2.9. Foundry Sand
Foundry sand is a by-product of ferrous and
nonferrous metal casting. It is high quality silica sand
with uniform physical characteristics. Foundry facilities
operate by purchasing high quality silica sand to make
casting molds and reuse the sand numerous times within
the foundry. Beneficial reuse of foundry sand continues
to become a more accepted practice as more end-users
are introduced to the concept. Beneficial applications of
foundry sand include aggregate replacement in asphalt
mixtures, Portland cement concrete, source material for
Portland cement, sand used in masonry mortar mixes,
embankments, retaining walls, subbase, flowable fills,
barrier layers and HMA mixtures.
2.10. Silica Fume
The environmental concerns necessitated the
collection and landfilling of silica fume to be mandatory.
Perhaps the most important use of this material is as
mineral admixture in concrete. Silica fume is added
to Portland cement concrete to improve its properties, in
particular its compressive strength, bond strength
and abrasion resistance. These improvements stem from
both the mechanical improvements resulting from
addition of a very fine powder to the cement paste mix as
well as from the pozzolanic reactions between the silica
fume and free calcium hydroxide in the paste.
2.11. Fly Ash
Fly Ash (FA) is the by-product of coal combustion in
power generation. Coal provides more than half of the
nation’s electricity and continues to be the fuel of choice
for generating power. Fly Ash is a powdery substance
laced with heavy metals such as arsenic, mercury and
lead. Fly ash can be an alternative to another industrial
resource, process, or application. These processes and
application include, but are not limited to, cement and
concrete products, structural fill and cover material,
roadway and pavement utilization, infiltration barrier and
underground void filling. It can be used as partial
replacement of cement because of its beneficial effects,
such as, lower water demand for similar workability,
reduced bleeding, reduce cracking at early age and lower
evolution of heat. High-lime fly ash has permitted normal
replacements of 25-40 and up to 75% of cement in
concrete materials for parking lots, driveways and roads.
2.12. Slag
Slag is a co-product of the iron and steel making
process. Once scorned as useless, it is now recognized as
a valuable material with many uses in agriculture,
environmental applications and in the construction
industry. Air cooled course aggregate is used in concrete
and asphalt mixes, fill material in embankments, road
base material and as treatments for the improvement of
soils. Ground Granulated Blast Furnace Slag (GGBFS)
has a positive effect on the flexural and compressive
strength of concrete. Expanded slag has low density
allowing for good mechanical binding with hydraulic
cement paste. Bulk density, particle size, porosity, water
holding capacity and surface area makes it suitable for
use as an adsorbent.
2.13. Swine Manure
The environmental effects of swine manure storage
systems and application methods are a concern, mainly
with respect to surface water, groundwater and air
quality as affected by odors and gaseous emissions from
large-scale swine production operations. To address
these concerns scientists (Fini and co-researchers) from
North Carolina A and T State University have found
ways to convert swine waste into bio-binder, replacing
petroleum based adhesives with bio degradable adhesive.
The viscosity of bio-modified binder is significantly
lower than that of non-modified binder. Reduction in the
binder viscosity can improve binder wettability which in
turn may improve mixture durability. Decrease in
stiffness and increase in relaxation capability of binder-
implies improvement in low temperature properties and
reduction in low temperature cracking. By adding 2% bio-
binder, one can maintain high temperature grade of binder.
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Table 1. Selected recycled materials and their construction applications
Innovative recycled material in construction applications
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
Hot mix Concrete Embank Base Mineral soil Waste water Alternative
Recycled material asphalt mixes ments Aggregate course filler stabilizer Adsorbent treatment Polymer Adhesive fuel
Swine manure × ×
Animal fat × ×
Silica fume × × ×
Roof × × × × ×
shingles
Palm bunch fiber ×
Citurs peels ×
Cement kiln dust × × ×
Fly ash × × × × × ×
Floundry sand × × × × ×
Slag × × × ×
Glass × × ×
Plastic × × ×
Carpet × × ×
Tire scraps × × × × × × × ×
Asphalt pavement × × ×
Concrete Aggregate × × ×
Gypsum ×
Sewage sludge × ×
2.14. Animal Fat
The use of animal fat has been used in the
construction industry since roman times. Animal fat also
referred to as tall oil. TOP has a strong connection with
cement providing a chemical adsorption interaction.
2.15. Citrus Peels
The US 2006/2008 seasons of citrus juice production
generated 10.6 million metric tons of waste. Research
shows that citrus peel can be an alternative to
commercial activated carbon that is high in capital and
regeneration costs, which is the preferred absorbent for
removal of Methylene Blue (MB). MB is a dye that
comes from the wastewater from textile industries and
can cause severe environmental pollution if emitted to
the environment without proper treatment.
2.16. Sewage Sludge
Course solids and bio solids accumulated in a
wastewater treatment process must be treated and
disposed of in a safe and effective manner-creating
sewage sludge. This material may be inadvertently
contaminated with toxic organic and inorganic
compounds. However, sludge ash has been investigated
in the production of concrete. Results of several studies
have indicated the benefits of using sewage slag ash in
concrete such as compressive strength, freeze- thaw
resistance and good hardening properties. Sewage sludge
ash may be used as a mineral filler substitute or as a
portion of the fine aggregate in hot mix asphalt paving.
Summary of selected recycled materials and their
applications in different construction project is tabulated
in Table 1.
2.17. The Survey
Sustainable-green infrastructure is growing concept
of saving energy, natural resources and cost, as well as in
the solution to environmental concerns involving waste.
In order to accomplish the growing industry of green
infrastructure, the end users including contractors,
engineers and suppliers have to be informed about what
recycled/waste materials are available to use in the
construction industry. To find out what end users are
aware of recycled and waste materials and who are
actually using them, companies have to be approached
and questioned. The survey intends to reveal the barriers
or issues behind not using recycled materials in the
construction industry. Results of the survey presents an
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initial understanding of the current strengths and
weaknesses of the practice intended to support
construction industry in developing effective policies
regarding uses of waste and recycled materials as
construction materials.
2.18. Methodology
A questionnaire survey was conducted through phone
calls, visits and email, addressing: (1) If the company
uses or sells any waste or recycled materials for
construction application, (2) Is the surveyor aware of
other recycled materials that are being used in
construction applications, (3) Are there any recycled
materials that are not recommended for use in the
construction industry and (4) if not using such materials,
what are the barriers behind not using recycled materials
in their work. All the questions ended with a yes for what
application and if no, reasons for not using the material.
The survey consisted of a list of recycled and waste
materials including; Cement Kiln Dust (CKD), fly ash,
foundry sand, slag, glass, plastic, carpet, tire rubber,
recycled asphalt, recycled concrete, gypsum, silica fume,
swine manure, animal fat, soy bean, roofing shingles,
citrus peels, sewage sludge, date and oil palm tree and a
place to add additional recycled materials being used in
the construction industry not listed. The last question
was included to record any additional contact or
references to question for more information on the topic.
3. RESULTS
The survey was compiled of 65 participants from 50
companies. The companies surveyed consisted of
contractors, engineers, architects and suppliers of
concrete, asphalt, landfills, scrap yards, steel
manufactures, drilling, demolition and recycling
companies. Table 2 shows the percentage for each type
of company surveyed. Figure 1 shows responses of the
surveyed companies on the most common recycled
materials. From this sample of companies, the most
common recycled material was Recycled Concrete at
15%; followed by Recycled Asphalt and Wood, with 12
and 8% respectively. Seven percent of the companies did
not use recycled material at all. There were a few
companies that were not included in the graph. These
companies used less than 2% of any given recycled
material including tire rubber, silica fume, glass, cement
kiln dust, carpet, foundry sand, swine manure, animal
fat, soy bean, citrus peels, sewage sludge and date and
oil palm tree, which were listed in the survey as usable
recyclable materials for construction applications. Other
materials that were mentioned that had a low percentage
usage were cast iron, copper, brass and sawdust.
Figure 2 shows the percentages of the most
commonly recycled materials used in concrete. Recycled
concrete was found to be the most popular at 54%, the
cost is low compared to purchasing natural stones and
aggregate and its availability is high because of
demolition of older buildings and highways. It should be
noted that, in order for concrete to be recycled and
reused as aggregate, it must be cleaned and washed for
DOT approval. Fly ash was very popular, with 20% of
companies using it in concrete. Companies noted that FA
is a great substitute for cement and it is cost effective.
Some companies mentioned slag (12%) and silica fume
(9%) for special projects, varying use according to the
engineer from job to job bases. Tire rubber (4%) was
found to be used in concrete including concrete barrier
applications. One company considered using cement kiln
dust and glass in their concrete, based on information
provided to them by the National Ready Mix
Association, but has yet to complete a testing strip.
Companies using recycled asphalt (57%), grinded the old
asphalt into course and fine course, then applied it to the
new asphalt paving process.
Another company mentioned that they reuse up to
40% recycled asphalt. Figure 3 shows the most
commonly used material in asphalt. There is also high
percentage of recycling roofing shingles (36%) that
asphalt companies use.
Of all the companies surveyed, 7% explained that
they did not use recycled materials due to cost, lack of
education regarding certain materials, limited to special
cases, environmental, quality of the product,
contamination, permits, separation process, lack of
market to buy the material, no equipment, storage, sent
to scrap yards and landfills and availability. Figure 4
shows the percent of reasons why companies are not
using recycled materials.
The companies surveyed, felt that cost made up 22%
of the reasons why they do not use certain recycled
materials in the construction industry. The cost
outweighs the benefits for using certain recycled
materials. Some processes are expensive to operate
including glass and the recycling tire scraps. Following
cost, companies claimed lack of education to be 13% of
the reason why certain recycled materials aren’t being
used in construction applications. Many companies
are unfamiliar or not sure of what recycled
materials can be used in construction applications.
Environmental constituted for 11% of the reasons.
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Fig. 1. Most commonly used recycled materials for construction applications
Fig. 2. Most commonly used recycled material in concrete
Fig. 3. Most commonly used recycled material in asphalt paving
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Fig. 4. Reasons of not using recycled materials
Fig. 5. Awareness of Recycled materials for construction applications
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Fig. 6. The percent of materials that need more data
Fig. 7. Why companies are using recycled materials
Environmental hazards include fly ash which contains
traces of arsenic and mercury, roofing shingles
containing asbestos and molding issues in some
gypsum. Quality of end products represents 11% of
the reasons why recycled materials were not utilized.
Contamination, which makes 8% of the reasons, was
another issue of not using recycled materials due to
the reduced performance of the applications. The need
to have permit for certain waste materials, high cost of
the separation process and lack of marketing of the
recycled material each represents 7% of why
companies choose not to use recycled materials.
Table 2. Types of applications
Application No. Percentage
Recycling 20 31
Construction 11 17
Concrete 9 14
Contractors 6 9
Asphalt 5 8
Engineer 4 6
Manufacture 4 6
Architect 2 3
Salvage 1 2
Association 1 2
Trucking 1 2
Steel 1 2
Total 65 100
Findings show that 14% of the companies are completely
unaware of other recycled materials being used in
construction. This suggests the need for education and
awareness programs to introduce the availability and
applicability of the recycled materials. Figure 5 shows
the percentage of materials the companies are aware of
in the construction industry
There are many other materials were not mentioned
in this survey, but can be used in different construction
projects. Recycled materials such as date and oil palm,
sewage sludge, citrus peels, soy bean, animal fat,
polyester lumber, rice husk and swine manure were
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among other materials that are poorly documented. The
reason for the underuse can be traced to new researches
and the lack of government approved regulations for
these materials, especially on state and government level
projects. In order to accelerate the growth of the use of
recycled materials in the construction industry, surveyed
companies suggested the need for more data to support
materials’ performance. Out of 50 companies surveyed,
results indicated the areas that need more research,
analysis and data before the use in construction
application as shown in Fig. 6.
When companies were asked about the benefits of
using recycled materials, reducing landfill waste was
number one at 38% followed by quality at 33% then
reduced cost at 27%. They attribute the quality to some
recycled materials that can improve strength such as silica
fume which can be used to produce high strength
concrete; fly ash improves the workability of the concrete;
and crumb rubber to improve thermal resistance. Cost may
be reduced by using recycled materials comparing to raw
materials. Figure 7 shows the results on why companies
are using recycled materials.
4. DISCUSSION
4.1. Statistical Analysis
As aforementioned, 65 participants from 50 different
construction related companies participated in this study.
Table 3. Percent use of recycled material
Material % Material %
Recycled concrete 15.0 Recycled asphalt 12.0
Wood 8.0 Shingles 7.0
metal 6.0 Fly ash 5.8
Gypsum 5.8 Brick 5.0
Slag 3.0 Steel 3.0
Aluminum 3.0 glass 1.0
Silica fume 2.0 Tire rubber 1.0
Klink dust 2.0 Foundry sand 1.0
Carpet 2.0 Soy bean 2.0
Swine manure 0.0 Animal fat 0.0
Citrus peal 0.0 Sewage sludge 1.0
Table 4. Reasons of not using recycled materials
Reason % Reason %
Cost 22 Marketing 7
Lack of education 13 Equipment 4
Hazards 11 Storage 4
Quality of end product 11 Availability 2
Contamination 8 Personal 10
Permits 7
Table 3 and 4 summarize the statistical findings of
the survey. Table 3 was generated from the responses
of companies that use recycled material and shows the
percent use of recycled material in different
construction applications, while Table 4 was
generated from responses of companies that do not use
recycled materials and shows the reasons why such
companies do not use recycled materials in their
products or applications.
5. CONCLUSION
Review of several studies suggested that the use of
recycled materials has positive impact through different
aspects. This include the benefits in enhancing
sustainability of the construction industry while reducing
cost, providing solutions to environmental pollution and
reducing the need for natural resources. In this study, a
questionnaire survey was conducted to find out the current
practices in using waste and recycled materials in the
construction industry. Results indicated that some
companies were not aware of the availability, quality of
the materials’ performance, cost savings, or any other
benefits including environmental benefits. It is, thus
recommended to create better documentation for green
infrastructure, connecting researches and industry with an
overview of what recycled materials are available for
different construction applications. Companies need to be
innovative in their use of recycled materials and reduce
their dependency on raw materials. Also, more data and
better documentations are needed to encourage the use of
waste and recycled materials in the construction industry.
6. REFERENCES
Abu-Lebdeh, T., S. Hamoush, W. Heard and B. Zornig,
2010a. Effect of matrix strength on pullout behavior
of steel fiber reinforced very-high strength concrete
composites. Constr. Build. Mater. J., 25: 39-46.
DOI: 10.1016/j.conbuildmat.2010.06.059
Abu-Lebdeh, T., S. Hamoush and B. Zornig, 2010b. Rate
Effect on pullout behavior of steel fibers embedded in
very-high strength concrete. Am. J. Eng. Applied Sci.,
3: 454-463. DOI: 10.3844/ajeassp.2010.454.463
Awwad, M.T. and L. Shbeeb, 2007. The use of
polyethylene in hot asphalt mixtures. Am. J. Eng.
Applied Sci., 4: 390-396. DOI:
10.3844/ajassp.2007.390.396
Begum, R.A., S.K. Satari and J.J. Pereira, 2010. Waste
generation and recycling: Comparison of conventional
and industrialized building systems. Am. J. Environ.
Sci., 6: 383-388. DOI: 10.3844/ajessp.2010.383.388
Johnny Bolden et al. / American Journal of Environmental Science 9 (1): 14-24, 2013
24
Science Publications
AJES
CalRecycle, 2006. Asphalt roofing shingles recycling:
Introduction. The California Department of
Resources Recycling and Recovery.
Ellie, H., I. Fini, L. Al-Qadi, T. Abu-Lebdeh and
J.F. Masson, 2011. Use of surface energy to evaluate
adhesion of bituminous crack sealants to aggregates.
Am. J. Eng. Applied Sci., 4: 244-251. DOI:
10.3844/ajeassp.2011.244.251
Emery, J.J., 1981. Potential uses for kiln dusts.
Proceedings of the Symposium on Mineral Fillers,
Ontario Research Foundation, (MFORF’ 81),
Toronto.
FHWA, 2004. Transportation Applications of Recycled
Concrete Aggregate. 1st Edn., Federal Highway
Administration, Washington, DC., pp: 38.
Fini, E. and T. Abu-Lebdeh, 2011. Bonding property of
bituminous crack sealants in the presence of water.
Am. J. Eng. Applied Sci., 4: 124-129. DOI:
10.3844/ajeassp.2011.124.129
Hamoush, S., T. Abu-Lebdeh, M. Picornell and S. Amer,
2011. Development of sustainable engineered stone
cladding for toughness, durability and energy
conservation. Constr. Build. Mater., 25: 4006-4016.
DOI: 10.1016/j.conbuildmat.2011.04.035
Hassim, S.J.M.S.A., 2009. The contractor perception
towers industrialized building system risk in
construction projects in Malaysia. Am. J. Applied
Sci., 6: 937-942. DOI: 10.3844/ajassp.2009.937.942
James, M.N., W. Choi and T. Abu-Lebdeh, 2011. Use of
recycled aggregate and fly ash in concrete
pavement. Am. J. Eng. Applied Sci., 4: 201-208.
DOI: 10.3844/ajeassp.2011.201.208
Kaosol, T., 2010. Reuse water treatment sludge for
hollow concrete block manufacture. Energy Resou.
J., 1: 131-134. DOI: 10.3844/erjsp.2010.131.134
Malakahmad, D., D. Amirhossein, C.M. Nasir, Z. Zaki
and M. Kutty et al., 2010. Solid waste
characterization and recycling potential for
university technology PETRONAS academic
buildings. Am. J. Environ. Sci., 6: 422-427. DOI:
10.3844/ajessp.2010.422.427
RMA, 2011. U.S. scrap tire management
summary.
Rubber Manufacturers Association, Inc.
Siddique, R., 2006. Utilization of Cement Kiln Dust
(CKD) in cement mortar and concrete-an overview.
Resources Conservation Recycl., 48: 315-338. DOI:
10.1016/j.resconrec.2006.03.010
Wang, Y., H. Wu and V.C. Li, 2000. Concrete
reinforcement with recycled fibers. J. Mater. Civil
Eng., 12: 314-319. DOI: 10.1061/(ASCE)0899-
1561(2000)12:4(314)
... The price of RCMs is among the main factors that directly affect their low market uptake. The common consensus in the literature is that RCMs are often more expensive than virgin materials, or that there is little to no price differential between virgin materials and RCMs (Bolden et al., 2013;Chick and Micklethwaite, 2004;Jin et al., 2017;Knoeri et al., 2011;Yuan, 2017). As explained by Chick and Micklethwaite (2004), construction projects operate under tight budgets and therefore, it is difficult to justify additional spending on a material when a cheaper alternative can fulfil the same function. ...
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... Increasing the production leads to increase waste materials that causes environmental, public health or aesthetic problems (Bolden J, et al 2013) and (Garrick G 2005). Recycling of waste material is the most appropriate economical solution to reduce the heavy onus on the landfills of the country (Bolden J, et al 2013). ...
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Chapter
House collapse implies when a house is knocked down or pulled down by fires or machinery. This paper addresses the secure operation of a demolition job and describes many phases before and when the demolition phase is underway. Throughout the demolition phase the various steps involved include inspecting, extracting toxic material, preparing a demolition schedule, the stabilization report and the precautions for precautionary protection which will be taken. Sled hammers, excavators, bulldozers, wrecking balls etc. and primary explosives used are key tools for these demolition operations, dynamites and RDX. The Implosion is known as explosive is used for the demolition. We recognize that each system is typically 100 years planned for a particular lifespan. The building's presence after the demise of its residents and adjacent structures is quite risky. It is also necessary that the building is demolished. Destruction includes the removal of structures, which requires the destruction of the structure and the retention of important reuse features. Different demolition techniques occur. Based on the form of building removal, the house is pulled down manually or mechanically. The blasting tools include hammers, rowing machines, rockets, bulldozers, wrecking balls and explosive explosives, which are typically found in big structures. They are dynamites and detonators. Before the demolition process, the different steps taken include the inspection of the destruction location, dangerous materials disposal and health preventive procedures. The research often concerns precautionary steps related to machines or structures, buildings, health and protection of the staff. Different demolition waste techniques in literature have been identified for the introduction of appropriate building demolition practices.
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Article
Problem statement: This research reuses the water treatment sludge fro m a water treatment plant to make hollow concrete blocks. The main objectives are to increase the value of the water treatment sludge from a water treatment plant and t o make a sustainable and profitable disposal alternative for the water treatment sludge. Attempt s were made to utilize the water treatment sludge a s a fine aggregate in the concrete mix for hollow con crete blocks. Approach: This study presented the results of these studies on potential applications of the water treatment sludge for beneficial uses. A concrete block is used as a building material in th e construction of walls. The concrete block construction is gaining importance in developing co untries. Results: The results in this study showed that the water treatment sludge mixtures can be use d to produce hollow non-load bearing concrete blocks, while 10 and 20% water treatment sludge mixtures can be used to produce the hollow load bearing concrete blocks. Economically, the 10 and 2 0% water treatment sludge mixtures can reduce the cost at 0.64 and 1.05 Thai baht per block, resp ectively. The 50% of water treatment sludge ratio i n mixture to make a hollow non-load bearing concrete block can reduce the maximum cost at 2.35 baht per block. Conclusion: Finally, the production of the hollow concrete blo cks mixed with water treatment sludge use as a fine aggregate in hollow concrete blocks, could be a profitable disposal alternative in the future and would be of the highe st value possible for the foreseeable future.
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Solid waste management is one of the major environmental concerns around the world. Cement kiln dust (KKD), also known as by-pass dust, is a by-product of cement manufacturing. The environmental concerns related to Portland cement production, emission and disposal of CKD is becoming progressively significant. CKD is fine-grained, particulate material chiefly composed of oxidized, anhydrous, micron-sized particles collected from electrostatic precipitators during the high temperature production of clinker. Cement kiln dust so generated is partly reused in cement plant and landfilled. The beneficial uses of CKD are in highway uses, soil stabilization, use in cement mortar/concrete, CLSM, etc.Studies have shown that CKD could be used in making paste/mortar/concrete. This paper presents an overview of some of the research published on the use of CKD in cement paste/mortar/concrete. Effect of CKD on the cement paste/mortar/concrete properties like compressive strength, tensile strength properties (splitting tensile strength, flexural strength and toughness), durability (Freeze–thaw), hydration, setting time, sorptivity, electrical conductivity are presented. Use of CKD in making controlled low-strength materials (CLSM), asphalt concrete, as soil stabilizer, and leachate analysis are also discussed in this paper.