Generation of Construction and Demolition Waste (CDW) in Portugal

1

Generation of Construction and Demolition Waste (CDW) in

Portugal

André Coelhoa and Jorge de Britob

a Department of Civil Engineering and Architecture, Instituto Superior Técnico, Technical, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisboa, Portugal

E-mail: [email protected]

b Department of Civil Engineering and Architecture, Instituto Superior Técnico, Technical, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisboa, Portugal

Tel.: + 351 218 419 709; Fax: + 351 218 497 650

E-mail: [email protected]

(Corresponding author)

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Abstract:

In line with the growing concern all around the world about Construction and Demolition Waste (CDW) management,

an attempt has been made to quantify the amount of CDW generated in Portugal, a country where no reliable / official

data exist. This is an increasingly important measure to companies, businesses and municipalities involved with CDW,

in a context of rising demands and more demanding recent legislation. One methodology is presented to quantify the

present generation, and another to extrapolate this generation over the next few years, up to 2020. It is concluded that at

present substantially less CDW is generated than the figure usually cited for Portugal, based on Spanish estimates,

although it is predicted that this value will be higher on a 10-15 year timescale, reaching over 400 kg/person/year.

Keywords: Construction and Demolition Waste, quantification, extrapolation

1 Introduction

Construction, demolition and rebuilding activities are still largely overlooked in Portugal when it comes to managing

CDW. Quantities are usually unknown, and even when monitored the resulting waste is neither sorted at the source nor

afterwards. Consequently, several landfill locations are reaching their maximum capacity, not to mention all the

materials wasted in land filling when most of them are recyclable. It has been shown [1] that CDW production (in

Portugal) is a greater problem, in strictly quantitative terms, than Municipal Solid Waste (MSW), which highlights the

need to implement measures to reduce the amount generated and to enhance its recyclability.

Although CDW only accounts for about one-fifth of the total waste production in Portugal [2], it is significant in terms

of overall weight, which is in line with the reported proportions of generated waste in other countries [3]. Estimates of

the CDW generation in Portugal have nevertheless been highly disproportionate, and too far apart to sustain any well-

grounded conclusion. In [4, 5, 6] global quantities of 25 253 ton/year, 6 440 000 ton/year (this figure was derived from

the usually cited quantity of 325 kg/person/year, for Portugal, originally from the study “Construction and demolition

waste management practices, and their economic impacts” (1999) [7]) and 63 614 ton/year are mentioned

(respectively), which shows how inconsistent the calculation of CDW generation still is, thus not providing a solid

framework quantity to be used in CDW management.

The rise in generation of CDW is, however, quite inevitable, not only because the amounts presently generated in

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Portugal (both those specified in document [7] and those calculated in the present work) are at the bottom of the

European figures presented in [7] (Figure 1) (with a mean European value of 502 kg/person/year), but mainly because

the construction of new buildings is slowing down, while retrofitting and demolition activities show a clear tendency to

rise for the next few years [8, 9]. Since these last activities generate considerably more waste per m2 than new

construction, generation can only rise in the medium term, and this study is an attempt to determine to what level.

The estimation of CDW generation in Portugal, one of those countries where positive data on this subject is either non-

existent or unreliable, is of primary importance, if proper environmental and economic analysis is to be undertaken in

this domain. Even so, a couple of figures on CDW generation in some locations have been collected. From sources

within the city of Barreiro municipality1, a generation of 12,6 kg/person/year(2) was determined, while for the Azores

islands a CDW generation of 260 kg/person/year has been reported [31]. As stated, CDW in Portugal is hardly accounted

for, which means that the entities which could or should have direct access to generation quantification locally do not

record CDW production. The fact that these numbers are highly disproportional (and in an odd fashion, since Barreiro

municipality has a much denser population - 2500 hab/km2 - than the Azores islands - 105 hab/km2) only shows how

inconclusive present local/regional CDW generation number comparisons really are.

Furthermore, if one is to design permanent central and mobile recycling stations on an industrial scale it is essential to

determine both the amount currently generated and likely to be generated in the future, since it is rapidly growing.

Finally, a certain amount of time is needed to implement functional industrial systems to provide CDW recycling,

which means that an accurate estimation of global CDW generation is quite useful/urgent.

Along with knowing the overall amount of CDW generated, it is also relevant to know the composition of the waste,

since it will inform investors, municipalities, waste managers and technicians about the materials they will have to deal

with, and in what proportions, before making any on-site waste survey or actually demolishing any building, which in

turn helps the decision-making process, saving a lot of time, money and resources. This aspect is not directly dealt with

in the present paper but constitutes a part of a wider study by the authors.

1 - Personal communication with engineer Carla Costa, from Barreiro’s Urban Hygiene Department. 2 - Figure determined from the source data of 100 m3/month, for mixed CDW, with a bulk density of approximately

830 kg/m3, in a municipal population of 79.012 (from Census 2001)

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2 Literature review

As stated above, several CDW generation estimates have been attempted for Portugal, without much agreement

between them. However, other countries’ CDW generation estimates are helpful for framing the present quantification

effort since, apart from specific differences in production, development level, political will and culture, the built

environment has many common aspects as well as relatively predictable trends in the inherent business models. For

instance, the retrofitting sector in Portugal has risen considerably, as it has in other European countries where building

renovation is the main investment sector in the construction industry, such as France, Denmark, Germany and Sweden.

Today it accounts for much more (around 22%) than is usually assumed (4 to 6%) [9]. In conjunction with an increased

number of demolitions [8] it is only to be expected that CDW generation will rise in the next few years.

Several studies on CDW generation quantification have been produced relating to both European and other countries

around the world.

The already cited reference [7] (Symonds, 1999), focusing on European Countries, positions Portugal below the average

of 502 kg/person/year with 325 kg/person/year. Germany is one of the leaders in terms of CDW generation, with 720

kg/person/year, while Ireland lies near the bottom of the table, at 162 kg/person/year. Other countries, e.g. the United

States of America, generate around 464 kg/person/year, with a total CDW generation of 136 million tonnes/year (as of

1996) [10]. The respective figures for CDW generation in Australia and Japan, according to [15], are 400

kg/person/year and almost 780 kg/person/year. Most of these figures are consistently higher than the usually cited

number for Portugal ( [7]).

Though new construction CDW generation is predicted to remain substantial in Portugal in the next few years (as

shown in the present work), demolition and retrofitting operations are very likely to increase in number, consequently

generating more CDW. In other countries, such as Germany, as much as 68% of all CDW generation comes from

demolitions and retrofitting works, annually amounting to 30 million tonnes, with new construction contributing 14

million tonnes, i.e. 32% [3]. CDW generation has been measured in Spain, whose construction market is similar to

Portugal’s [11], giving figures of 0.12 m3/m2 in new construction, contrasting with 0.86 m3/m2 in demolitions - 7 times

higher. The EU average has been estimated at 40 million tonnes per year in new construction, with around 175 million

tonnes per year in demolition and retrofitting jobs, which shows the importance of the latter to CDW generation and

management.

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Outside the European Community, for example in the U.S.A., over 90% of all CDW is generated in demolition and

retrofitting operations (and this figure does not even include public works like roads, bridges and urban streets), which

emphasizes the importance of tackling reduction, separation and recycling in these operations, which should have

priority over new construction.

In spite of the usually regarded as high levels of CDW generation, several uses are already being given to construction

materials diverted from the waste stream, by reusing them directly or by enforcing recycling operations that allow their

reinsertion in the economy:

• Recycling of CDW inert aggregate in road construction - this is by far the major CDW material recycling

destination, especially aggregate resulting from waste concrete, stone and ceramic masonry, roof shingles and tiles.

Many authors have studied this application, which has been growing steeply, especially in developed countries ([16]

through [20]);

• Fabrication of concrete with recycled aggregates - this application has encountered difficulties in its implementation,

essentially due to huge demand of aggregates for road construction (usually down-cycling concrete waste

aggregate), technical quality issues in building regulations, cost competition with virgin aggregates, and lack of

knowledge and awareness from involved professionals. However, much research on recycled concrete has been

undergone ([21] through [26]);

• Reuse and recycling of other construction materials, such as ceramic bricks, tiles and timber, is already happening at

both research and practice level ([27] through [30]). Applications range from direct reuse of salvaged bricks, post-

processed plastic covering materials, re-fabrication of wood elements (from deconstruction sites), post-processed

glass elements, and even reuse of prefabricated concrete constructions [15].

3 CDW quantification methodology

For Portugal, where until less than a year ago it was not compulsory to declare the estimated CDW production or to

dispose of it only in CDW-dedicated dumping grounds, no indices have been calculated like those mentioned above for

Spain (based on actual CDW measurements on site). Therefore, information about material quantities was drawn from

real building projects (available in Lisbon’s municipal construction archive), selected by date of construction and type

of use - housing or commercial - in order to estimate the mean CDW generation figure in kg/m2 for each category, in

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demolition and retrofitting operations. For CDW generated by new construction, the numbers cited for Spain in [11]

were used, due to the similarities between the new buildings construction industry in the two countries. Finally, in

estimating the CDW generated by the rehabilitation and demolition of roads and highways, real figures were used, in kg

of each material, converted into kg/km, over a total of 422 km of upgraded/demolished roads, in 2007.

Figure 2 shows a simplified diagram of the calculation method which separates types of buildings, types of operations

and the public works contribution to the global CDW generation estimate. In each case, the calculation method follows

the procedure described below.

In the case of the demolition of residential blocks, the weight per unit area was calculated by examining the existing

building plans, resulting in the figures presented in Table 1. The construction date is important as it defines a probability

of demolition, according to Table 2. Obviously, the older the buildings the more likely they are to be demolished, which

is connected with their level of degradation (an attempt was made to quantify this). The resulting weighted average

amounts to 2210 kg/m2 in terms of the living area (1964 kg/m2 in terms of the useful area). In the case of renovation of

residential blocks, weighting according to age does not apply since it was considered for simplicity’s sake that all

spaces in buildings (renovation consisted of the retrofitting of areas inside buildings, rather than an intervention in the

building as a whole) have the same probability of being retrofitted. Furthermore, CDW from renovation must be divided

into demolition and new construction waste, since the two are separate activities and generate different amounts of

waste (per unit area). Therefore, while the demolition part of the rehabilitation effort simply amounts to the direct mean

value of the quantities shown in Table 3, which means 566 kg/m2 in terms of the living area, quantifying the new

construction part involves adding the input from building non-structural walls (69.3 kg/m2, from Table 4) and finishing

materials (38.9 kg/m2, from Table 5). Overall, retrofitting residential blocks generates approximately 742 kg/m2 of

CDW, in terms of the living area. Estimating the generation from building totally new blocks, on the other hand, mainly

consisted of adding the total values in Table 4 to those in Table7 (using Tables 5 (traditional heavy materials) and 6

(modern lightweight materials generally used for new commercial buildings) for the generation of CDW from finishes

in new construction), giving a final figure of 190.3 kg/m2.

A similar approach was used for commercial buildings, for each type of operation, demolition, rehabilitation and new

construction (Tables 8 and 9). Table 10 shows the CDW estimates calculated for both housing and commercial

buildings. It can be clearly seen that demolition operations generate the greatest amounts of CDW, while retrofitting is

next (between 4 and 7 times less than demolition), since it involves demolishing some components and building others.

Finally, as expected, new construction is at the bottom, with commercial buildings leading to the least generation since

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they include more lightweight materials.

For public works, in this case only roads and highways, a total of 175 million tonnes of CDW were generated in 2007 in

upgrading works on an important road management company’s road network, an extension of roughly 245 km.

However, an estimated 422 km have been subjected to intervention, since around 177 km of the state-owned part of the

road network were also modified in 2007 (information based on the site:

https://www.portaldeempreitadas.pt/ListaConcurso.aspx). So a rough total of 300 million tonnes of CDW was generated

in 2007, excluding all non-contaminated soil and stones (which accounted for 95% of all resulting materials). Divided

by the total length of road stretches subjected to intervention in 2007, a total of 715 thousand tonnes of CDW per km

were generated during that year.

4 Future trends - Extrapolation methodology

To determine the CDW generation per person (per year), estimates had to be derived for the total amount, in m2, of new

construction, retrofitting and demolition of housing and commercial buildings. These estimates are all based on

statistical data [8], taking the average useful area of commercial buildings estimated for the year 2006, based on a value

of 12.2 m2 of useful area per person [13]. The areas in question are shown in Table 11. These overall areas of

intervention (for buildings) multiplied by the amount of CDW each activity generates make it possible to calculate the

total CDW generated for the whole country. With a population of 10 599 095 inhabitants (2006 census [14]), the

generation figures per inhabitant for 2007 (kg/person/year) are calculated and summarized in Table 12.

Table 12 shows that operations involving housing construction generate the greatest amount of CDW (over 70%),

which highlights the need to reduce CDW generation in this sector of the economy. Commercial buildings only account

for 13% of the total, while public works generate around 15%. Due to great differences in intervention area between

new construction and building demolition (for both housing and commercial buildings), the waste generated by new

construction is currently (2008) equal to or higher than that arising from demolition, even though the CDW produced

per square metre is considerably lower (Table 10). It is also important to note that the calculated value for present CDW

generation is considerably lower than the figure usually quoted for Portugal: 325 kg/person/year [7]. This difference can

be attributed to the still strong presence of the new construction sector in Portugal, with its rather low CDW generation

per m2. But this is changing rapidly, which implies greater waste production in the near future (as estimated in this

study).

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Extrapolation for the prediction of future CDW generation rates was based on statistical series of municipal licences [8]

(shown in Table 13) for new construction, demolition and retrofitting, which were used to define continuous functions

for calculating future CDW generation. Two possible situations were considered for these functions, scenario 1 that

assumes no change in each of the derived curves, and another that considers three variation stages - scenario 2. Using

these values, these curves were best fitted, using polynomial functions, as shown in Figure 3.

Extrapolation values - scenario 1

Extrapolating the exact functions until the year 2020 and using the proportion of number of licences in each year taking

2008 as the reference year, the values of CDW generation were calculated, resulting in the curves shown in Figure 4. So

the corresponding CDW generation table can be produced for the year 2020 (Table 14). It is clear, in this scenario, that

the retrofitting of existing buildings becomes the most relevant form of CDW generation, in both housing and

commercial buildings. This is related, of course, to the fact that the fitted governing curve for the retrofitting data is of

the 4th degree, with a fast growing tendency after 2006. Without any measure to counteract this trend, the figures

rapidly increase, which means that some kind of consideration must be assumed in order to justify a certain stabilization

in the variation curves (which leads to extrapolation scenario 2). Also, the demolition CDW generation rises

considerably to reach around twice as much in 2020 as in 2008. However, the global trend (red line in Figure 4, sum of

all other lines, for each year of the analysis) remains for the most part controlled by the retrofitting curves, maintaining

their basic shape, which shows its impact on the overall trend. The final generation, as of 2020, amounts to 605.6

kg/person/year.

Extrapolation values - scenario 2

This extrapolation scenario basically considers three stages of evolution in the licences awarded, dividing the series

1999 - 2020 into equal periods. The first uses the existing statistical data, the second (2007 - 2013) uses the function

defined by the previous period data best fit to derive yearly values, and the third consists of a stabilising form (justified

by an expected cooling of the economy reflected in the construction industry), simply obtaining each value by

calculating the average of the previous two. This rule is applied to all CDW data categories, best fitting the figures

obtained for each year for each category, and Figure 5 is plotted. Taking the same 2008 yearly CDW per person

generation figures (Table 12) and using this progression, the resulting CDW evolution can be seen up to the year 2020

in Figure 6, which results in Table 15, for the last year of the analysis.

The stabilising part of the functions obviously means that the final total CDW generation figure (for the year 2020) is

much lower than the same figure in extrapolation scenario 1 (37% of the latter). However, it must be stressed that, while

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in scenario 1 the intervention surface almost doubles, in this scenario it remains approximately constant. Figure 6 shows

that global CDW generation is mostly dictated by housing blocks, in which the waste generation from demolition

activities tends to equal the amount for new construction, but without surpassing it. Retrofitting generation also rises

substantially, but is still much less than the other operations in housing blocks. In this scenario public works generate

the third greatest curve, maintaining a considerable share in the total CDW generation (17.5%, compared to 10.3% in

scenario 1, for the year 2020). It must also be stressed that in spite of the foreseen reduction in new construction activity

(in terms of m2 constructed for housing and commercial buildings alike), this category will remain one of the most

important sources of CDW in the near future. Global CDW generation reaches 226 kg/person/year.

5 Conclusions

The number of municipal licences issued over time was a governing factor for this analysis, even though this meant an

approximation in terms of the number of buildings actually constructed, retrofitted or demolished. The existing

statistical data for this segment is better populated (it goes back to 1994) and more complete (the statistical data series

on present finished cases only starts in 2000 and there is no information on retrofitting and demolition). Other

approximations were considered, mostly for calculating the CDW generation per m2 of housing and commercial

buildings from only a few existing cases, which are assumed to represent whole groups of buildings set to be

demolished and retrofitted. Also the new construction generation is based on volumetric amounts of waste averaged

from a few real cases (for the Spanish construction industry) which can scatter widely. Finally, the amounts of waste

considered for public works, although based on real cases, are dependent on the number of kilometres assumed or

targeted for demolition/retrofitting that can vary considerably from one year to the next (despite the recent world

financial crisis, a boom in new roads and highways is expected in the next few years).

In spite of all the approximations involved, however, the results of extrapolation scenarios 1 and 2 can be meaningfully

analysed in the context of the present state of the industry. Scenario 1 is seen as a maximum, given that the curves are

assumed to progress through time without any change, and scenario 2 is viewed as a minimum, since complete

stabilization within only 14 years (from 2006 to 2020) may also be fairly considered to be too swift as far as the trends

are concerned, within an ever-changing economic pattern. It is therefore considered more likely that the actual evolution

of CDW generation in Portugal is somewhere near the average of scenarios 1 and 2. So the final generation figure for

the 2020 horizon would be 415.7 kg/person/year, which, taking into account the values cited for the EU and their

average [7], makes some sense as far as CDW generation evolution for Portugal is concerned. Nevertheless, this study

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estimates a current global generation of 185.6 kg/person/year, which is lower than the usually cited (but never proved)

figure of 325 kg/person/year [7]. But CDW is predicted to rise to over 400 kg/person/year in the next 10-15 years,

taking the sum of all waste generation activities within the construction industry. Regional studies are needed not only

to back these overall values but also to provide guidance on where to install permanent CDW recycling plants and on

how much CDW they should be designed for.

6 Acknowledgments

Thanks are due to the FCT (Foundation for Science and Technology) for the postdoctoral research grant awarded to the

first author and to the ICIST - IST research centre.

7 References

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Table 1 - CDW generated by demolishing housing blocks

Buildings Location CDW generation over the

total construction area, kg/m2 CDW generation over the useful area, kg/m2

CDW generation over the living area kg/m2

Date of construction (approximate)

1 Av. Duque de Loulé,

42, Lisbon 1129 1975 2189 before 1919

2 Rua de São Ciro, 37,

Lisbon 1759 2715 3125

between 1946 and 1970

3 Av. Óscar Monteiro Torres, 18, Lisbon

1376 1722 1778 between 1946 and

1970

4 R. Prof. Santos Lucas,

Lote F, Lisbon 1285 1829 2338

between 1971 and 1990

5 Polis Cacém, Lisbon 315.3 463.4 543.6 between 1919 and

1945

Note: Definitions of total construction area, useful area and living area are given in Portuguese legislation as, respectively, the full envelope area of construction, plus areas such as parking spaces or common circulation areas, the operational/functional residential area and the exclusive housing area where people tend to be more static (excluding, for instance, bathrooms).

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Table 2 - Percentage of buildings targeted for demolition, sorted by construction date (derived from [12])

Date of construction Very degraded Needing extensive repair To be demolished

Before 1919 41.07 34.59 38.45

between 1919 and 1945 33.64 29.45 31.95

between 1946 and 1970 18.80 19.17 18.95

between 1971 and 1990 5.96 10.27 7.70

between 1991 and 2001 0.53 6.51 2.95

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Table 3 - CDW generation from retrofitting housing blocks (demolition)

Buildings Location CDW generation over the

total construction area, kg/m2

CDW generation over the useful

area, kg/m2

CDW generation over the living

area kg/m2

Date of construction

(approximate)

1 Av. Conde Valbom, 89, Lisbon 91.7 102.4 124.5

Not relevant 2 Estrada de Benfica, 482, Lisbon 449.0 541.0 1268

3 R. Azevedo Gneco, 69, Lisbon 176.8 216.1 305.8

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Table 4 - CDW generation from building new non-structural walls

Material % in volume Density, kg/m3 Typical void index, % Material weight, kg/m2 % in weight

Concrete/mortar/tiles 84 2400 0.39 67.64 97.6

Metals 1 0.495 0.71

Paper and cardboard 7 0.385 0.56

Plastics 4 0.0286 0.04

Wood 3 0.294 0.42

Other 1 0.457 0.66

Total 69.30

Note: Based on reference [11]

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Table 5 - CDW generation from building new finishes (traditional heavy materials)



Metals 4 1.800 4.6


Plastics 13 0.0845 0.2

Wood 7 0.623 1.6

Gypsum 20 5.933 15.3

Other 1 0.415 1.1

Total 38.89


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Table 6 - CDW generation from building new finishes (modern light materials)



Metals 4 1.800 12.49


Plastics 30 0.195 1.35

Wood 15 1.335 9.26

Gypsum 25 2.596 18.01

Other 1 0.415 2.88

Total 14.41


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Table 7 - CDW generation from building new structural components



Metals 8 1.080 17.8


Plastics 12 0.0234 0.39

Wood 60 1.602 26.4

Total 6.07


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Table 8 - CDW generation from demolishing commercial buildings

Buildings Location CDW generation over the total

construction area, kg/m2 CDW generation over the

useful area, kg/m2 Date of construction

(approximate)

1 Rio Sul shopping mall, Lisbon 35.2 51.8 between 1971 and 1990

2 Building 82 - ANA, Lisbon 258.1 379.4 between 1946 and 1970

3 Collective dressing-rooms

Gulbenkian, Lisbon 1637 2354 between 1946 and 1970

4 Building with17 floors, Lisbon 2410 3542 between 1971 and 1990

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Table 9 - CDW generation from retrofitting commercial buildings (demolition)

Buildings Case identification CDW generation over the total

construction area, kg/m2 CDW generation over the useful area, kg/m2

Date of construction (approximate)

1 Av. da Igreja, nº 4F, Lisbon 190.2 192.6

Not relevant 2 Av. Conde Valbom, 89A, Lisbon 104.1 162.1

3 R. Ramalhão Ortigão, 47A, Lisbon 358.1 409.5

4 R. Tenente Ferreira Durão, 55B, Lisbon 204.6 279.2

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Table 10 - CDW generation estimates for housing and commercial buildings from demolishing, retrofitting and new construction

Type of operation

Type of building

Housing Commercial

kg/m2 (1) kg/m2 (2) kg/m2 (3) kg/m2 (2) kg/m2 (3)

Demolition 2210 1964 1265 2982 2054

Retrofitting 746.2 445.5 347.3 409.5 315.4

New construction 190.3 167.9 114.3 132.0 89.8

Notes: (1) m2 of living area; (2) m2 of useful area; (3) m2 of total construction area (see note in Table 1)

24

Table 11 - Anticipated intervention areas, for housing and commercial buildings

Type of construction Area of expected intervention, million m2

New construction Retrofitting Demolition

Housing buildings 4.535 0.112 0.209

Commercial buildings 0.889 0.079 0.041

Notes: Figures calculated for 2007; Housing areas refer to living areas; Commercial building areas refer to useful areas

25

Table 12 - Total CDW generation in kg/person/year (estimate for 2008)

Housing blocks

New construction 81.41

Retrofitting 7.86

Demolition 43.2

Commercial buildings


Retrofitting 2.09

Demolition 11.46

Public works Retrofitting/demolition 28.48

Total 185.6

26

Table 13 - Statistical series of municipal licences for construction, demolition and retrofit, in Portugal

Number of licences Year

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006

New construction 40927 40184 40581 43877 48274 52094 49932 48688 47638 42392 38953 37962 38602

Year-on-year change, % -1.82 0.99 8.12 10.02 7.91 -4.15 -2.49 -2.16 -11.01 -8.11 -2.54 1.69

Demolitions 313 181 230 195 290 388 372 409 2237 1964 2372 2103 2134

Year-on-year change, % -42.17 27.07 -15.22 48.72 33.79 -4.12 9.95 446.94 -12.20 20.77 -11.34 1.47

Renovation and restoration Change and reconstruction

Retrofit 4631 4365 4850 5017 5020 5069 4992 5040 4542 4446 3448 3645 3709

Year-on-year change, % -5.74 11.11 3.44 0.06 0.98 -1.52 0.96 -9.88 -2.11 -22.45 5.71 1.77

27

Table 14 - Total CDW generation in kg/person/year (estimate for 2020 - extrapolation scenario 1)

Housing blocks


Retrofitting 284.17

Demolition 94.3



Retrofitting 75.54

Demolition 25.01


Total 605.6

28

Table 15 - Total CDW generation in kg/person/year (estimate for 2020 - extrapolation scenario 2)

Housing blocks


Retrofitting 24.81

Demolition 59.9



Retrofitting 6.60

Demolition 15.87


Total 225.8

29

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Germ

any

Austria

Belgium

Denm

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Spain

Finlan

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European Union countries (15)

CD

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Figure 1 - CDW generation in 15 European Union countries, according to [7].

Figure 2 - Simplified diagram of the global CDW estimation methodology.

30

Number of municipal licences evolution in Portugal, from 1999 to 2006

y = 0,1576x2 - 315,78x + 1999

R2 = 0,6977

y = 0,0295x3 - 119,23x2 + 120531x + 1999

R2 = 0,9354

y = 1,3791x4 - 11031x3 + 3E+07x2 - 4E+10x + 2E+13

R2 = 0,9189

0

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20000

30000

40000

50000

60000

1999 2000 2001 2002 2003 2004 2005 2006Year

num

ber o

f lic

ence

s New constructionDemolitionRetrofittingpolynomial function (demolition)polynomial function (new construction)polynomial function (retrofitting)

Figure 3 - Number of construction-related municipal licences in Portugal (new construction, retrofit and demolition) - 1994 to 2006.

CDW generation evolution, for 2006 - 2020, in extrapolation Version 1

0

100

200

300

400

500

600

2006 2008 2010 2012 2014 2016 2018 2020years

kg/p

erso

n.ye

ar

Housing blocks - new constructionHousing blocks - retrofittingHousing blocks - demolitionCommercial buildings - new constructionCommercial buildings - retrofittingCommercial buildings - demolitionPublic works- retrofitting/demolitionTotal

Figure 4 - Predicted CDW generation in Portugal based on polynomial functions (2006 - 2020, extrapolation scenario 1).

31


y = 0,0226x3 - 61,44x2 - 27534x + 1E+08

R2 = 0,9841

y = 0,0167x6 - 200,82x5 + 1E+06x4 - 3E+09x3 + 4E+12x2 - 3E+15x + 1E+18

R2 = 0,9774

y = -0,5179x3 + 3110,4x2 - 6E+06x + 4E+09

R2 = 0,9602

0

10000

20000

30000

40000

50000

1999 2001 2003 2005 2007 2009 2011 2013 2015 2017 2019

Year

num

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s

New constructionDemolitionRetrofittingpolynomial function (New construction)polynomial function (Retrofitting)polynomial function (Demolition)

Evolution based on the tendency line defined by the previous years data

"Stabilization" evolution, with each value being iqual to the simple average of the two previous ones

Figure 5 - Number of construction-related municipal licences evolution in Portugal (new construction, retrofitting and demolition) - 1994 to 2020 (extrapolation scenario 2).


0

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2006 2008 2010 2012 2014 2016 2018 2020Years

kg/p

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Housing blocks - New constructionHousing blocks - RetrofittingHousing blocks - DemolitionCommercial buildings - New constructionCommercial buildings - RetrofittingCommercial buildings - DemolitionPublic Works - Retrofitting/DemolitionTotal

Figure 6 - Predicted CDW generation in Portugal based on polynomial functions (2006 - 2020, extrapolation scenario 2).

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Generation of Construction and Demolition Waste (CDW) in Portugal

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