performance of cdw when the mortar screed is incorporated ... · performance of cdw when the mortar...

Performance of CDW when the mortar screed is

incorporated

EXTENDED ABSTRACT

Rui Pedro Borges Pragosa

Dissertation abstract for Civil Engineering Master

Jury

President: Prof. Dr. Jorge Manuel Caliço Lopes de Brito

Supervisor: Prof. Dr. Pedro Miguel Dias Vaz Paulo

Other jury members: Prof. Dr. Fernando António Baptista Branco

October, 2012

https://fenix.ist.utl.pt/homepage/ist14171

Performance of mortar screed incorporating CDW– EXTENDED ABSTRACT

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1. Introduction

1.1. General information

The evolution and population growth are realities visible around the world, including Portugal.

The building / construction is part of human activity developed aligned with of population growth.

This activity has attempted to cover the deficiencies, increasing the standard of living of the population.

Thus, the construction industry is responsible for the consumption of many natural resources, as well as,

the production of construction and demolition waste (CDW).

We all know that is a add value needed for human race, the construction has caused over the

years various Environmental damage, not only in Portugal but also around the world, the recycled

construction and demolition landfills are causing one of the major environmental impacts to the

planet.

It is therefore essential to consider viable alternatives to this widespread deposition. It was based

on this idea that this dissertation was working out, aiming to seek new alternatives to the filing of CDW

in landfills, with the primary focus on the reuse / recycling of waste. We must not forget what is truly

important to safeguard the management of CDW according to already published also in Portuguese

Decree-Law Nº 46/2008 of 12 March, which establishes a system of management operations RCD thus

helps the prevention and reuse well as collection, transportation, storage, sorting, treatment, recovery

and finally disposal only.

1.2. Scope and methodology of the investigation

In the first phase were presented details on the state of the art after some intensive study and

research literature on the topic, describing the life cycle of buildings, going through a phase of further

development of waste management and the importance of reporting CDW and its various applications.

We also studied the characteristics of mortars in general and further the screed mortar, taking account

of the work done so far. All this research has been done to better understand the methodology to be

adopted in the laboratory tests / experiments in order to retire the best conclusions.

In the second phase are elaborated all experimental tests established for the preparation of this

thesis given the results we want to achieve. Here is presented carefully and have all the tests and all

values obtained from these tests.

In the third phase are analyzed and discussed all values based on comparison of the actual

values of mortar screed in all tests performed.

Finally draw up conclusions of all the work done, hoping that they are the best and that the

study reached a conclusion beneficial to the use of CDW.


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2. Database

2.1. Framework

The world population has increased significantly in recent centuries. Since 1950 has increased

more than twice already coming to almost 7000 million people today. All this increase in population has

led to a large increase of the global economy, and this increased fivefold since 1950 despite all the crises

as in the example of the 1997 crisis that began in East Asia. Besides this crisis, this year the global

economy has expanded and grew at a rate of 4.1% (UNPD).

These data lead us to important environmental changes, because with population growth and

the growth of the global economy, the use of natural resources has increased significantly. The building

was one of the most important activities with this development, causing very negative effects on the

environment due to overuse of natural resources to meet the increased quality of life and to correspond

quickly and easily with this increase as expressive of the population.

Throughout history human beings have been improperly exploit natural resources to produce

several types of materials. In fact, during most of the nineteenth century the dominant concept was the

existence of unlimited natural resources. The anthropocentric notion was dominant and geographical

context, progress was synonymous with growth, development and achievement of nature.

All the exploitation of these natural resources is carried out due to the large industrialization

and as I said, also due to the large increase in population and economic. All this over-consumption is

very negative for the environment, causing big changes, affecting negatively the quality of soil, air and

water resources.

Given these negative changes is essential to the world that appear new behaviors and attitudes

able to modify such an event. This time, it was essential to start study up several ways to solve this

problem of CDW, being this an important study to try to solve all these problems.

2.2. CDW

After this small initial framework, it is important to start talking about all the waste caused in

construction and demolitions, called CDW. These can be of various types, quantities and volume,

covering all ranges of "waste" caused by constructions and demolitions that human beings feel the need

to do so that their species grow in an easy and convenient way.

It is important starting now with the definition of waste, which by law now stands for "any

substance or object which the holder discards or intends or is required to discard" and even the more

precise definition of construction and demolition waste (CDW), which correspond to "all waste from

construction, re-construction, extension, alteration, maintenance and demolition of buildings collapse."


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This problematic situation of land filling of CDW led to the emergence of new strategic models

capable of safe a sustainable construction, such as Waste Management of Construction and Demolition.

Regarding the issue of waste, words to consider are REDUCE, REUSE and RECYCLE, presenting waste

disposal as the last possible hypothesis.

But to understand what the CDW are is also essential to know its composition and its

properties. These waste generated in the construction industry may have various types and

classifications, and can be divided into three distinct types, inert waste, and these are the majority and

those who do not suffer physical, chemical and biological important, hazardous waste and even the non-

hazardous, and therefore required a careful screening work in order to achieve separating all hazardous

materials that may contaminate the inert waste.

Taking into account the properties of the CDW, these are essential for producing a good mortar

with these same aggregates, because the material employing the new mortars should be suitable for

specific purpose for which it is intended final product, thus it was necessary to understand and study

their physical and chemical structures of various recycled aggregates natural raw materials. Thus it was

essential to check all the properties of the new recycled aggregates as well as the more correct

percentages to obtain the replacement mortars at the end of great quality.

A variety of properties of the recycled aggregates is high because its composition, the

equipment used and the fineness of water absorption and other factors can degrade the final state of

the mortar modified. The main differences between these and conventional aggregates are larger water

absorption grains, heterogeneity of the composition and even the slightest mechanical strength of the

grains.

After restarting before knowing the composition and properties of CDW was essential to verify

the existence of advantages in recycling CDW. Besides the law only requires the project management of

construction and demolition waste in public works, should be taken as good practice where the work

justifies it as is the case with major works and special features.

You can then states that a good management CDW is closely linked to good recycling CDW

which entail numerous advantages. Recycling CDW is then a very important practice in terms of

environmental sustainability or want constructive. These numerous advantages that recycling brings out

the following:

• Decrease the obvious use of landfills as a means of waste disposal;

• Increased energy savings;

• Preservation of existing natural resources and its natural reserves;

• Mitigation of all environmental impacts;

• Reduction of pollution emitted in the manufacture of new materials;

• The creation of jobs and increase competitiveness by creating new businesses in the area.


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Once achieved the rewards of recycling CDW was essentially a classification homogeneously

poles is very important in view of the excessive increase in the production of this type of waste. Thus

defined a European Waste List (EWL) at European level to which they are identified and treated in a

more objective. The European waste list is divided into distinct classes and 20 to 17 classes that we are

interested in this work, since it is this class that are the CDW as shown in table 2.1 below.

LER Code Description

17 01 00 Concrete, bricks, tiles and ceramics

17 02 00 Wood, glass, plastic

17 03 00 Bituminous mixtures, coal tar and tarred products

17 04 00 Metals (including their alloys)

17 05 00 Soil (including excavated soil from contaminated sites),

stones and dredging spoil

17 06 00 Insulation materials and construction materials

containing asbestos

17 07 00 Mixing of construction and demolition waste

17 08 00 Materials based on plaster

17 09 00 Other construction and demolition waste

The CDW are typically not classified as dangerous, but nevertheless always existed some CDW

considered hazardous, namely containing components considered dangerous such as asbestos and lead.

Taking into account the costs arising from the recycling of CDW, the ordinance in force n º

73/2011 of 17 June, are implemented values of charges for waste management which entail costs to the

management of systems for managing specific waste streams , individual and collective. Having regard

to Article 58. Rates of these waste management annually and have concerns about the amount of waste

managed entities, and these rates following values:

2 € / Ton of municipal waste and inert waste from construction and demolition waste

land filled;

5 € / Ton of construction and demolition waste land filled inert;

2.3. Mortars

After talking CDW, it is missing speak about of mortars and all their properties more relevant.

The use of mortars shows great longevity originating over 8000 years ago, where our ancestors used a

mixture of clay with water so they can build their new shelters. The development of this technique has

presented major developments, essentially at the level of the type of binder used.

Table 2.1 - LER Codes of CDW (Adapted from [Decree-Law n º 209/2004])


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Currently presented as a construction material consisting of a mixture of one or more binders,

for aggregates, additives, for products which confer special properties to these mortars, this being

added only optional, depending on the desired requirements, and water added to work in the case of

industrial mortar dried and / or stabilized, where water is also added to manufactures.

The mortars consist of linked parts which are one of the most important constituents of a

mortar, without them stuck where all the constituent materials of a mortar was not possible because

the linked parts are added to the mixture which provide the capability of agglutination. They consist of

aggregates still, these being defined according to EN 998, as a granular material which is not involved in

the reaction of hardening of the mortar. Aggregates are cross linked materials of various sizes, with a

material that presents not cohesive and chemical activity almost null. Mortars are also used as

constituents for mixing the water, this being one of the most important constituents for a mortar,

because without it the paste is not formed, as is water that causes chemical reactions for this purpose.

This should preferably be drinking water so there is no contamination in the mixing and its main

functions hydration of hydraulic binders as I said the immersion of aggregates and defining the

workability of the mortar. Finally, the components used are the additions and adjuvant.

3. Experimental campaign

3.1. Introduction and Planning

After defining all relevant aspects in the composition of mortar screed incorporating CDW

passed the tests themselves prepared in the laboratory of Secil Martingança.

The experimental campaign that followed it aimed to evaluate the performance of screed

mortars with partial replacement of aggregates for CDW. For this evaluation were chosen two different

vectors to start studying such performance, the first vector incorporating CDW as they came from the

factory collection and recovery after reducing particle size less than 4 mm and a second vector

incorporating CDW withdrawing from first vector still all fine smaller than 0.125 mm. Both the first

vector and second vector, we performed an embodiment dosed in different rates of replacement of

natural aggregates commonly used in this type of mortar by CDW at 10%, 15% and 30%, presenting the

study as the most relevant percentages to arrive at a better conclusion of the work performed. These

tests were performed at 7 and 28 days of healing as the norm of mortar screed so requires. In these

days of curing was then conducted two tests compressive strength and flexural strength at 7 and 28

days, and these binding assays, and assays were also performed to determine the density and modulus

of elasticity, but these only 28 days of curing.

The experimental phase was then divided into three major groups, namely:

• Initially we studied the usability of the CDW screed mortars, as well as made a crushing and

processing of all this stuff for later use.


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• After this first stage is passed to the preparation of all mixtures for the production of mortar

screed already incorporating the CDW in different percentages was set as 10%, 15% and 30%. Then still

large at this stage we performed the dents and the preparation of all samples for experimental placing

these samples under conditions of perfect cure.

• Last but not least, comes the actual experimental phase where all tests are performed already

spoken previously and which will be reported later in a more special care. It also applied the new mixing

mortar screed abroad to better understand the whole reality of implementation and workability.

When thinking about performing a mixture for producing mortar screed of their main

constituent are to be incorporated into the aggregates, cement and water. As such, the methods used in

this work are exactly the same but with a further embodiment of a new material, being the construction

and demolition waste, so to be able to assess its effect on the new mixed mortars.

3.2. Collection and treatment of CDW

To start this study was essential to achieve the CDW capable of being used in new mortar

screed. This time, after extensive market research collection, treatment and recovery of CDW I realized

that this is a market already very visible in our country, i.e., with many companies in the industry, but

few with treatment and screening appropriate. This whole process of valuation of CDW only has any

meaning if the market be able to absorb the currently does not.

The company with the longest history and largest commitment to treatment and recovery of

CDW is the company in Seixal, SGR Environment, which features large facilities with a production line of

waste very complex, this being the most complex in this area in Portugal. As such I contacted them and

went to their facilities to realize the true reality of this business. It is a company that receives daily many

trucks with construction and demolition waste and where their production line and processing of CDW

work all year without ever stopping.

Checking through the production line material that would be more appropriate for my study I

chose to bring the material thinner than they can produce on their production line having a particle size

between this 0mm and 12 mm, and even so a material with a particle size greatly exaggerated for the

production of mortar screed still a need for crushing being used in an experimental stage, as later

described.

Once collected on all CDW factories and then welcomed into the lab, they were analyzed

visually, noting that this was a very thick material for incorporation in this new mixture of mortar screed.

This time, we performed a pre-grinding machine itself through all the material by crushing two to three

times consecutively, preserving still a small percentage of that happens if the original material is a

problem with the ground product. After all this work with the crusher and collect all the material already


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crushed, were made in various laboratory tests to find out the quality of the received material in factory.

This time the tests were carried out:

Determination of moisture content of CDW;

Determination of the percentage of fines;

Determination of particle size curve.

3.3. Assays

After all these tests has produced the campaign trial itself starting from the outset in the

preparation of samples for testing.

Once all samples were prepared and placed in excellent curing conditions, was carried out to

prepare a mixture for applying the new mortar screed embedding CDW outside. This was another

experimental campaign needed to truly understand the ability of the new mortar.

Once everything was set up, immediately began to carry out tests to 7 days and then testing to

28 days, as well as the application of new mortars abroad. After all tests withdrew the results of all the

experiments, drawing up drawing up charts and tables that an interpretation of these results become

more precise and more accurate. Then be analyzed all tests conducted.

3.3.1. Assays to the modulus of elasticity and to density

Assays to the elasticity modulus and to density were made so that all samples withdrawn from

curing conditions perfect. Thus began at the outset with determining the densities of all samples to 28

days. It began by weighing each specimen using a balance accurate to 0.1 g and then there were all the

values in a table, then using the equation 3.1 presented:

being,

MV – density (kg/m3);

m - mass of the sample in kg;

V - volume of the sample in m3.

After the calculated densities passed to the calculation of the elastic moduli, which immediately

began by calibrating the machine with the aid of a calibrator. And then at the end of the machine be

properly calibrated and adjusted, passed the tests proper elasticity modulus.

EQUATION 3.1


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Thus, assays were started and were withdrawn and recorded in tables all values from the

machine testing of the elastic modulus, passing to the calculation of the elastic modulus using for this

the following equation 3.2 given:

⁄

being,

ME - Modulus of Elasticity (MPa);

c - time of sound propagation (μs);

t - time of wave propagation registered (μs);

MV – Density (kg/m3);

g - acceleration of gravity (m/s2);

ϑ - Poisson's ratio.

3.3.2. Assays to flexion and to compression

To start the test, withdrew from the wet room all samples to initiate this step after having been

in a position of pure perfect. Thus began was then determine the resistance to bending of the test

pieces with standard mortar screeds and then determined the compressive strength of the same screed.

The calculated values of flexural strength and compression are calculated as follows:

Flexural strength

being,

f - flexural strength (MPa or N/mm2);

F - maximum applied load (N);

l - distance between supports (mm);

b - width of the prism (mm);

d - the prism thickness (mm).

Compressive strength

EQUATION 3.3

EQUATION 3.4

EQUATION 3.2


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being,

f-Compressive strength (N/mm2 or MPa);

F - maximum applied load (N);

A - area of compression zone (mm2).

After testing flexural and compressive for screed mortar standard worked up similarly for the

remaining mortar screed under study with the incorporation of 10%, 15% and 30%.

After all samples tested and removed all numerical values that were derived therefrom became

easier to get the experimental results and the resulting conclusions.

3.3.3. Results of the tests

This time is presented below in Table 3.1 all gains and losses after elaborate completed all

experimental tests.

Essay 7 days

standard 10% CDW 15% CDW 30% CDW 10% CDW

s/ thin 15% CDW

s/ thin 30% CDW

s/ thin

flexural strength (MPa)

2,03 1,78 1,69 0,99 1,81 1,77 1,21

Gains / Losses (MPa)

- 0,25 0,34 1,04 0,22 0,26 0,82

compressive strength (MPa)

8,48 6,84 6,73 3,73 7,21 6,57 5,12


- 1,64 1,75 4,75 1,27 1,91 3,36

Essay 28 days

Modulus of elasticity (MPa)

25861,25 21351,09 21728,03 14018,71 21519,93 19997,15 17081,05


4510,16 4133,22 11842,54 4341,32 5864,1 8780,2

Density (MPa) 2042 1974 1956 1940 1957 1942 1934


68 86 102 85 100 108

flexural strength (MPa)

3,4 3,02 2,79 2,01 3,07 2,59 2,25


- 0,38 0,61 1,39 0,33 0,81 1,15

Table 3.1 – Gains and losses on existing resistance tests at 7 and 28 days


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compressive strength (MPa)

14,25 12,07 12,45 8,48 12,57 11,66 9,79


- 2,18 1,8 5,77 1,68 2,59 4,46

3.3.4. Real application

This application abroad was excellent to see the reality of the possible need to use this new

material by technicians. This was an experiment carried out by an expert so that construction began by

mixing any two screed mortars and then placed them on the pavement.

After restarting before prepared and placed the two screeds abroad wanted to understand the

differences as well as what the actual behavior of the new mortar. This time, the expert answered a

short survey on the behavior of the new mortar screed as is visible in Table 3.2.

Consideration Acceptable Good Average Poor

Manual application X

Grip with Ruler X

sarrafar X

trowel X

stroking X

After the results presented in Table 3.2 by the appreciation of mason specializing was easy to

see that the new mortar screed with the incorporation of CDW without the material on the sieve of

4mm and no fines, presents an acceptable application in all aspects, reason makes this study very

positive once in conversation with mason specialist he feels that the application of this new mortar is

very similar to applying the mortar has manufactured and marketed by SecilMartingança.

3.4. Cost analysis

Having regard to the study presented, this only can identify beyond the laboratory study of all

tests is an analysis of all costs arising in drafting the new mortar screed for so if you can compare all the

costs.

Table 3.2 – Consideration Mason after applying the mortar screed incorporating CDW material without the 4 mm

sieve and then will be analyzed without finos.de all tests conducted.


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It was so important to immediately set up several points that were used as a basis of

comparison for proper cost analysis. The costs analyzed are based on the commercial value of the bag

screed off the central SecilMartingança, Maceira, to market, with the company other generation plants

with different costs. Thus, taking as a basis of comparison of the mortar screed manufactured and

marketed by Secil Martingança, we started by setting the price per pound of mortar screed, which is the

price to beat the new mortar screed incorporating CDW.

It began by defining the treatments from obtaining the raw material through the crushing and

subsequent drying of any material until its junction as a single material. Thus various costs were

presented as material that wants to work, dividing the costs as follows:

• Cost of coarse aggregates;

• Costs of fine aggregates;

• Cost of siliceous aggregates.

After obtaining all these costs, it becomes easier to calculate the final price of the entire screed

mortar mixture as manufactured by SecilMartingança. Thus the calculation is performed taking into

account the percentage of each aggregate embedded in the mortar making a mixture of one kilogram to

thereby be able to compare the price per kilogram leaving the factory Maceira.

4. Conclusion

This experimental work was very important to be able to understand what the reality in

Portugal and in Europe the CDW produced and what its final destination. It was also important to find

out the feasibility of using CDW screed mortars and as such all the tests were done we could give you

the best advice on this aspect taking full advantage of all this study.

In the course of this work could be concluded that there is a massive production, both in

Portugal and in Europe, waste and construction and demolition that are not always run smoothly. With

this study it was concluded that there are about 180 million tons of waste produced annually in the

European Union, 180 million of which only 28% are reused / recycled, these numbers are very alarming

and very disturbing that must be fought by all of us who work day to day with this problem.

Taking into account the situation of construction waste and demolition in the EU study was

carried out at this present work and has directed at the outset to effective resolution and fast all these

environmental concerns thus countering weak reuse existing of CDW. Making a first conclusion of this

work is easy to realize that there are numerous ways to solve the issue of recycling of CDW, where the

reuse of these CDW in mortar screed was the way found by me faster and more effective to deal with

the excessive production of CDW.

performance of cdw when the mortar screed is incorporated ... · performance of cdw when the mortar...

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