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Construction waste disposal practices:
the recycling and recovery of waste
A. Puskás1, O. Corbu1, H. Szilágyi2 & L. M. Moga3
1Department of Structures,
Technical University of Cluj-Napoca, Romania
2National Institute of Research and Development URBAN-INCERC,
Cluj-Napoca Branch, Romania
3Department of Buildings and Management,
Technical University of Cluj-Napoca, Romania
Abstract
The rate of recycling and recovery of construction and demolition waste for the
year 2020 is set at 70%. Currently in Romania, the waste recovery level is far
below the set value, the collected waste is mostly disposed of by storage in
landfills, without any other recovery or reuse. This paper presents practices
in recycling of waste obtained from the construction of new buildings and
demolition of existing buildings, with the potential of recovering large amounts of
construction waste as filling material for road infrastructure or for heavy loaded
industrial floors as well as possible other applications for using construction waste
to substitute natural resources in concrete composition, obtaining material
embedding waste with low energy consumption. The presented solutions might
lead to an important increase of the recycling and recovery percentages,
contributing to the fulfilment of the targeted and recycling, recovery and reuse
rate. The viability of the possible applications is demonstrated with practical
examples.
Keywords: construction waste, road infrastructure, recycling, recovery and
reuse, natural resource substitution.
1 Introduction
The built environment in which we live has a substantial impact on the natural
environment. The construction industry represents a major energy consumer
domain, with a value of about 40% from the total energy consumption at EU level,
WIT Transactions on Ecology and The Environment, Vol 191,
www.witpress.com, ISSN 1743-3541 (on-line)
© 2014 WIT Press
doi:10.2495/SC141102
The Sustainable City IX, Vol. 2 1313
generating 30% of the total CO2 emissions [1]. The same source highlights the fact
that the building sector shows an increasing trend over the past years [1]. At the
same time, the construction sector is one of the pillars of economic development,
accounting for 10% of the gross national product in developed countries and
20–30% in developing ones [2]. In 2012 the construction sector generated 8.6%
of Romania’s gross domestic product [3], not including the results of the building
materials industry, e.g. cement production. At the same time due to the large
number of employees in the construction sector it also has a substantial social
impact when it upholds tens of millions of jobs. The quality of the built
environment has a considerable impact on energy and material resources,
implicitly being a decisive factor that affects inhabitants’ health, comfort and
productivity.
The construction industry demands approximately 3–4 tonnes of material per
capita every year and generates over 1 tonne of waste per capita [4]. The national
waste management policy should be in line with the goals of the European policy
in order to prevent waste generation and should aim to reduce resource
consumption and practical application of the waste hierarchy. The Frame Directive
2008/98/EC on waste, transposed into national legislation by Law No. 211/2011,
sets up the basic principles of waste management: no hazardous effects on people
and environment, no ill-effects for water, air, soil, plants or animals, no
disturbances by noise or smells and with no negative impact on the landscape and
special interest areas. These principles are to be applied in their hierarchical
priority: prevention (reduction), preparation for reuse, recycling and other
recovery operations [5, 6].
The rate of recycling and recovery of construction and demolition waste
(recycling and other material recovery, including waste disposal on landfills using
non-hazardous waste to substitute other materials) for the year 2020 was set at
70% [7]. By definition, construction and demolition waste derive from activities
like the construction of buildings and infrastructures, total or partial demolition of
buildings or infrastructures, road construction and maintenance.
The data made available by the Ministry of Environment [8] show that even if
the recovery of waste from construction and demolition has increased in recent
years (Figure 1), it has been made by landfill, almost the entire quantity of waste
being disposed of by storage with no other real recovery.
Most of the waste management practices adopted in the past were oriented to
short-term solutions, without taking into account the long-term effects on the
environment. Therefore, palpable actions should be taken to apply the best
available technologies for reducing, recovering and reusing waste. The first step
in this manner is to develop the relevant code/norm provisions in order to allow
extensive reuse of construction and demolition waste and/or to develop new
materials from waste, usable at a similar rate to the existing generated waste
volumes, which can ensure the possibility of further re-use and which is able to
ensure the desired continuity for the life cycle of the construction materials,
especially of those obtained from waste (Figure 2).
WIT Transactions on Ecology and The Environment, Vol 191,
www.witpress.com, ISSN 1743-3541 (on-line)
© 2014 WIT Press
1314 The Sustainable City IX, Vol. 2
Figure 1: The situation of the construction and demolition waste (thousand
tons) in Romania [8].
Figure 2: Desired life cycle of construction materials.
2 Construction and demolition waste management practices
In the European Union annually about 850 million tons of construction and
demolition waste is generated, which represents 31% of the total waste generated
in the EU [2]. In the composition of construction and demolition waste there are
0
100
200
300
400
500
600
700
800
900
2006 2007 2008 2009 2010 2011
TotalC&Dwaste
collected
Recovered
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materials like concrete, bricks, wood, glass, metals, plastic, solvents, asbestos and
excavated soil, many of them being recycled by various processes.
According to the European Topic Centre on Sustainable Consumption and
Production (Eionet) [2], from the entire construction and demolition waste, the
concrete, bricks, tiles and ceramics wastes amount to approx. 78% (Figure 3).
Figure 3: The weight of various types of materials in construction and
demolition waste [2].
The same source concludes that this type of waste can be a source for recycling
and reuse in the construction industry, being established as a priority management
direction by the EU [2]. Due to the very large quantities of construction and
demolition waste, they occupy important storage areas in landfills. Moreover, if
they are not separated at source they might contain traces of hazardous substances
(Figure 4).
Figure 4: Demolition wastes as landfill – with potential for recovery.
The potential resource for recovery of construction and demolition waste
includes the large number of deteriorated or abandoned buildings, most of them
built in a previous period, whose life stage approaches the demolition phase, the
existing waste having resulted from already performed demolition works, which
is temporarily stored or abandoned, and also high quality waste resulting from
on-site construction activity or other redundant materials, with quality below the
imposed standards values.
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1316 The Sustainable City IX, Vol. 2
According to the European Aggregates Association (UEPG), in 2009 the
European aggregates market totalled approx. 2.9 billion tons, dropping by 17.1%
against 2008 levels (extracted and processed in about 23,000 facilities), out of
which the secondary and recycled aggregates amount to as low as 7% [9]. For the
next years the forecasts indicate an increase of the aggregates market to 4 billion
tons per year, therefore it is imperative to enhance mineral waste recycling degree
with a view to achieving effective aggregates, and to use mineral waste to replace
non-renewable resources.
The realisation of concrete using recycled aggregates might present an
important deviation with regard to the one realised using natural aggregates,
therefore further research is necessary in the field in order to use mineral waste as
aggregate in concrete composition.
3 Demolition waste for heavy loaded floor infrastructure
3.1 Presentation of the building to demolish
Abandoned industrial areas became of high interest for new industrial
developments. These areas often include structural skeletons as a challenge to
complete, but due to their advanced deterioration they represent only potential
waste (Figure 5).
Figure 5: Structural skeletons in industrial areas in advanced deterioration.
When existing buildings are condemned to give space for new ones, their waste
potential can be salvaged locally (Figure 6) mainly as filling material. Due to
further development plans of the client, to the low quality and variability of the
filling on the existing land, to the low bearing capacity of the soil as well as to
the existence of underground foundations in order to level and to improve the
existing area, a significant quantity of filling material becomes necessary (Figure
6). The three storey reinforced concrete frame building with masonry fill-in walls
(Figure 7) became unnecessary for the client, also disturbing the path of the
proposed new building. It has been used for decades as a social building, deserving
the plant activity, being renovated from time to time to ensure the minimum comfort
for employees. Therefore it presented not only limited possibilities for material
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retrieval, but important quantities of hazardous waste. Due to the environmental
commitment of the client, demolition of the building with waste separation was
chosen, also targeting the maximum reuse of the generated waste.
Figure 6: Structural skeletons in industrial areas in advanced deterioration.
Figure 7: Multi-storey building to demolish.
3.2 Demolition and reuse of the waste
The challenge to complete is to comply with the requirements of the client in order
to maximise waste reuse. Priority in the works has been to remove and collect all
the hazardous waste (like roof insulation, mechanical equipment, etc.) according
to the specific waste management norms, representing only a minor percentage of
the total produced waste. All architectural materials have been collected as waste,
while all the PVC doors and windows have been retrieved for further incorporation
in other buildings, with attention to the labour quality. According to the labour
statistics during the retrieval of the PVC doors and windows, the labour cost is
increased by circa 15% with regard to the usual demolition techniques, caused by
high attention to the retrieved material handling and protection. Bricks from the
masonry walls have been recovered, as well as all the metallic parts including
the reinforcing bars of the structures.
The structure has been demolished using special equipment (Figure 8) and then
crushed locally (Figure 9). Difficulties appear with the separation of the structural
concrete of the rendering and masonry, the resulted filling material presenting a
significant percentage of impurities (Figure 10).
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1318 The Sustainable City IX, Vol. 2
The filling material obtained by crushing the structural waste had to be sorted
after the crushing but prior to using it for the heavy loaded floor infrastructure,
involving extra labour and cost. All the complication could be avoided with an
appropriate demolition technological process and care for the size of the recycled
aggregates. In the case shown, due to exaggeratedly large sizes of the
recycled aggregates interlard of the filling bed has been almost impossible to
obtain.
Figure 8: Demolition equipment on site.
Figure 9: Crushing of the structural concrete locally.
Figure 10: Filling material with impurities obtained after crushing.
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The cost of obtaining the crushed recycled aggregates is comparable with the
price of the ballast if the optimum technological process is established in order to
obtain recycled aggregates reused locally. When the recycled aggregates do not
contain impurities as a result of the appropriate technological process and the
recycled aggregates’ size is optimal, the cost of the recycled aggregates is justified
to lay between the cost of ballast and of the crushed stone.
In order to replace the ballast and the stabilised ballast layer, the complete
filling has been done using recycled aggregates (Figure 11). Due to the size
deviations of the recycled aggregates, the compaction phase takes longer
compared to the ballast or crushed stone. In the compaction phase, if the recycled
aggregates have been properly splashed, the dust and small parts of the recycled
aggregates act like a binder, creating an almost compact layer. Results obtained
for the deformation modulus of the industrial floor substructure have been
surprisingly good, showing more than 10% higher values than in the case of using
natural aggregates.
Figure 11: Filling with recycled aggregates.
4 Conclusions
Using recycled aggregates locally could represent an adequate solution for roads
or heavy loaded industrial floor substructures, comparable with the natural
aggregates and also in the cost and deformation modulus obtained, also solving
the problem of significant quantities of construction and demolition waste. Lack
of code provisions for reusing aggregates is still raising doubts with regard to the
rightness of the solutions. Solving the problem of construction and demolition
waste is the responsibility of all the parties involved in the construction industry.
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References
[1] Eurostat, http://epp.eurostat.ec.europa.eu/portal/page/portal/eurostat/home/
[2] European Environment Information and Observation Network,
http://www.eionet.europa.eu/
[3] National Institute of Statistics, http://www.insse.ro/cms/en
[4] D. Leopold, M. Goga, R. Meissner , Ghid privind gestionarea deşeurilor din
construcţii şi demolări, Sibiu, Casa de Presă şi Editură Tribuna, 2011
[5] Directive 2008/98/EC on waste, http://ec.europa.eu
[6] National Law No. 211/2011 on waste
[7] National Agency for Environmental Protection, http://www.anpm.ro/
[8] Ministry of Environment and Forests, http://mmediu.ro
[9] European Aggregates Association – UEPG, http://www.uepg.eu/
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