SAMARIS

Sustainable and Advanced MAterials for Road InfraStructure

DeliverableD24

Environmental annexes to road product standards

Competitive and Sustainable Growth (GROWTH) Programme

Document number: / SAM-GE-DE24 / Version: / 2 / Date: / 16.01.06
Name and signature / Date
Drafted: / Sabine Boetcher, Klaus Krass
Reviewed: / Cliff Nicholls
Verified: / Wolfgang Bernrieder
Validated: / Pat Maher
Approved by SAMARIS Management Group:

SAMARIS

ABSTRACT

This paper makes proposals how environmental sustainability requirements of road materials could be included in the European Product Standards for road materials in form of an annex. the need for such annexes arises from the goal of the European Commission to incorporate environmental requirements into the second generation of the European Product Standards for construction materials according to the essential requirement “Hygiene, health and environment”. In relation to these construction materials, the main focus is on recyclable (road) materials and industrial by-products which can be used as aggregates for unbound and bound mixtures. For natural aggregates, the environmental compatibility is assumed to be given by default. The procedure of this task was split up into four steps: After identifying the relevant road materials, the appropriate European Product Standards were selected. The next step was to detect the potential hazardous components and the appropriate test methods. Finally, drafts of annexes to the Product Standards were developed, duly formatted so as to be suitable for future standardisation. Beyond the recommendations given, there is also a need to standardise the methods for analysis(e.g. PAH and sulphur in reclaimed asphalt) in form of supporting documents. Proposals for these methods are given in a sepeate paper.

TABLE OF CONTENTS

ABSTRACT......

TABLE OF CONTENTS......

EXECUTIVE SUMMARY......

1introduction......

2ProcedURE......

3Identification of relevant Road Materials......

3.1General......

3.2Assessment procedure of selected industrial by-products......

3.3Assessment procedure of selected recycled materials......

4Identification of Appropriate european standards......

5Identification of hazardous components and appropRiate test methods......

6drafts of Annexes to Product standards......

6.1General......

6.2Draft for an environmental annex on aggregates for bituminous mixtures......

6.3Draft for an environmental annex on asphalt concrete......

6.4Draft for an environmental annex on reclaimed asphalt......

6.5Draft of environmental annex no aggregates for unbound and hydraulically bound materials

6.6Draft of environmental annex on unbound mixture specifications......

6.7Handling tar-bound reclaimed road material......

7Conclusions......

8References......

Appendix A: Test for Tar......

Appendix B: Test for Sulphur......

Appendix C: Annex to EN 13043......

Appendix D: Annex to EN 13108-1......

Appendix E: Annex to EN 13108-8......

Appendix F: Annex to EN 13242......

Appendix G: Annex to EN 13285......

EXECUTIVE SUMMARY

SAMARIS is a European research project that is part financed by the European Commission through the GROWTH thematic programme in the 5th Framework Programme, FP5. The objective of GROWTH is to support “Competitive and sustainable growth”. The SAMARIS project is developed from a FEHRL-initiative in 2000 and contains 11 work packages of which seven are technically based. The highway stream of the project is structured with five different work packages.

Work Package 4, entitled “Safety and Environmental Concerns in Material Specifications”, is a part of the pavement stream and primarily concentrates on addressing safety and environmental aspects in product standards, for example the detection and classification of hazardous characteristics in road materials. The WP is organised in three tasks.

Deliverable 24 is the output of task 4.3 and is entitled “Environmental Annexes to Product Standards”. The aim of task 4.3 is to make proposals about how environmental sustainability requirements of road materials could be included into the European Product Standards for road materials in the form of an annex. Justification for such annexes is derived from the goal of the European Commission to incorporate environmental requirements into the second generation of the European Product Standards for construction materials according to the essential requirement “Hygiene, health and environment”. This subject wasnot a part of the mandates for the different construction materials that have been standardised to date. Therefore, the present first generation of European standards for road materials donot include any regulations concerning environmental specifications.

In relation to these construction materials, the main focus of task 4.3 is on recyclable (road) materials and industrial by-products which can be used as aggregates for unbound and bound mixtures. For natural aggregates that have been used in road materials for generations, the environmental compatibility is assumed to be given by default and there is no need for further testing.

In addition to the input from other tasks of Work Package4, input has been derived from other Work Packages of this project, particularly Work Package 3 dealing with the assessment of alternative materials.

After identifying the relevant road materials which are usedwithin this task, the appropriate European Product Standards have beenidentified. The next step was to detect the potential hazardous components and the appropriate test methods. Finally, drafts of annexes to Product Standards were developed, duly formatted so as to be suitable for future standardisation.

Concerning industrial by-products, the following residuals from steel production and from burning of coal and of lignite as well as municipal solid waste incinerator bottom ash have been identified as being relevant for possible use in European countries:

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SAMARIS

  • Municipal solid waste incinerator bottom ash
  • Crystallised (or air-cooled) blast furnace slag
  • Vitrified (or granulated) blast furnace slag
  • Basic oxygen furnace slag
  • Electric arc furnace slag
  • Coal fly ash
  • Boiler slag
  • Fly ash from lignite combustion.

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The range of the essential chemical constituents of these materials has been described. With regard to the processed municipal solid waste incinerator bottom ash, the range of essential components in its ash are listed.

Concerning recyclable materials, it was found to be advisable to deal not only with mineral construction waste but also to deal separately with bitumen-bound material (reclaimed asphalt) and with tar-bound materials.

Tar, especially coal tar and other tar distillates, was used as a road binder in the past in many European countries because its hazardous properies were not widely known at that time.

The hazardous characteristics of the listed materials are mostly chemical properties which refer, in each case, to a certain concentration in an eluate.

The chemical characteristics relevant for the European countries are listed in tables that differentiate between the different material. The tables donot include threshold values because they are also dependant on the test method used, which, together with the requirements,have not beenthe same in all the European Countries for a long time.

With regard to the relevant standards, the main focus was on the standards of the following Technical Committees of CEN:

  • CEN/TC 336 “Bituminous binders”
  • CEN/TC 154 “Aggregates”
  • CEN/TC 227 “Road materials”

Most of the harmonised European standards are relevant as well as, in some cases, the “voluntary” European standards.

Starting from the considerations discussed above, the last chapter proposes drafts for environmental annexes to product standards. As examples for typical future product standards, environmental annexes for hEN13043, hEN13108-1, hEN13108-8, hEN13242 and EN 13285 have been drafted.

In addition to these environmental annexes, a separate annex dealing with possible handling of tar-bound reclaimed road material (TB) has been proposed in a separate section.

The proposed drafts in the Appendices of the report should be a help for people involved in standardisation, particularly those on CEN Technical CommitteesTC154, “Aggregates”, and TC227, “Road materials”.

Beyond the recommendations given, there is also a need to standardise the methods for analysis(e.g. PAH and sulphur in reclaimed asphalt) in the form of supporting documents. Proposals for these methods are given in Deliverable N° 23.

The hope remains that such environmental annexes will expand into the next generation of road product standards in order to enforce the safety when dealing with industrial by-products and recycled materials.

The handling of tar-bound reclaimed road material is covered separately due to the fact there is no European standard for this material. It can be stated that the re-use of that material is possible but only in cold mixtures in order to avoid air pollution by dangerous components, such as PAH.

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SAMARIS

1introduction

Five years ago, the Forum of European National Highway Research Laboratories (FEHRL) proposed two projects called MAP (Materials for Asphalt Pavement) and STRIM (Structures in Maintenance) which were finally merged in a research and development project called SAMARIS (Sustainable and Advanced MAterial for Road InfraStructure). This project is part of the Growth programme of the 5th Framework programme and is jointly financed by the European Commission and the project partners’ national resources. The project period was fixed from 1stJanuary 2003 to 31stDecember 2005.

The SAMARIS project is separated in two technical streams. On the one hand, there is the pavement stream that is subdivided into five Work Packages and, on the other hand, the structure stream that is also structured in different Work Packages.

Work Package 4,entitled “Safety and Environmental Concerns in Material Specifications”,is a part of the pavement stream and primarily concentrates on addressing safety and environmental aspects in product standards, for example the detection and classification of hazardous characteristics in road materials. The WP is organised in three tasks. The key objective for task 4.1 is to produce an overall procedure including appropriate test methods for the identification of hazardous components in road materials regarded as being recyclable. In doing so, emphasis will be on asphalt. Task 4.2analyses the need of an investigation of reaction of pavement materials to fire. Existing tests were checked for their applicability and new test methods were developed were it was found to be necessary.

This report is the output of task 4.3and is entitled “Environmental Annexes to Product Standards”. The aim of task 4.3 is to make proposals how environmental sustainability requirements of road materials could be included in the European Product Standards for road materials in form of an annex. Justification is derived from the goal of the European Commission to incorporate environmental requirements into the second generation of the European Product Standards for construction materials according to the essential requirement “Hygiene, health and environment”. This subject wasnot a part of the mandates for the different construction materialsthat have been standardised so far. In relation to these construction materials, the main focus of task 4.3 is on recyclable (road) materials and industrial by-products which can be used as aggregates for unbound and bound mixtures. It has to be ascertained whether very different experience has been gainedwith the application of these materials in different European Countries. In any case, the requirements for these materials do vary significantly.

In addition to the input from Work Package4, input has been derived from other Work Packages of this project, particularly Work Package 3 dealing with the assessment of alternative materials.

After the identifying the relevant road materials to be usedfor this task, the appropriate European Product Standards are identified. The next step in the proceeding was to find the potential hazardous components and the appropriate test methods. Finally, drafts of annexes to the Product Standards were developed, duly formatted so as to be suitable for future standardisation.

2ProcedURE

The task proceeding is subdivided into four steps (seeFigure 2.1):

Step 1:Identification of relevant road materials

Step 2:Identification of appropriate European Product Standards

Step 3:Identification of hazardous components in road materials and appropriate test methodsfor their determination

Step 4:Drafts of annexes to Product Standards

Step No. / Action / Input from / Example
1 / Identification of
relevant road materials / / WP 3 / Industrial by-products, tar bound materials
2 / Identification of
appropriate European Product Standards / / CEN/TC 154
CEN/TC 227 / EN 13043
prEN 13108-8
EN 13285
3 / Identification of
hazardous components and appropriate test method / / WP 3
Task 4.1
Literature / Leaching test
Detection of sulphur, PAH
4 / Drafts of annexes to Product Standards

Figure 2.1:Proceeding – Flow chart

In order to make the content of these steps clearer they shall be in detail explained in the following:

Step 1:The identification of the relevant road materials was strongly based on the relevant input from Work Package 3. Additionally, a literature review was carried out for other potentially useful sources of information for the work. The results of the investigations are those road materials dealing with in the next steps.

Step 2:Step 2 was to identify those European Product Standards where the above mentioned road materials are covered. These standards are mostly part of the work programmes of Comité Européen de Normalisation (European Committee for Standardisation,CEN) Technical Committees TC 154 “Aggregates” and TC 227 “Road materials”.

Step 3:The hazardous componentsfor each road material identified in step 2were defined along with an appropriate test method for determination of the relevant component. A decisive criterionfor all of themis the path of danger,e.g.the transport of the hazardous component by air, by soil or by water. For this objective, the work of task 4.1 wasincorporated.

Step 4:In this last step, drafts of annexes to some typical standards with environmental requirements were prepared. In doing so, the question as to whether the drafts shouldincludethreshold values for the requirements or whether more rather general advice should be given is discussed.

3Identification of relevant Road Materials

3.1General

Deliverable N°16 of the SAMARIS project, entitled “Methodology for assessing alternative materials for road construction” (SAMARIS, 2005) reviewed eight alternative materials. These materials can be subdivided into industrial by-products and recycled construction waste.

The industrial by-products selected were:

  • crystallised blast furnace slag
  • vitrified blast furnace slag
  • basic oxygen furnace slag
  • electric arc furnace slag
  • coal fly ash
  • municipal sold incineration bottom ash

These sixindustrial by-products were selected as the result of an enquiry in the European countriesinto which, unfortunately, Germanydidnot participate. Other residuals from power plants, such as boiler slag and fly ash from lignite combustion, have an importance in Germany (FGSV, 2003 and 2004; Krass et al., 2004), so that these two industrial by-products were added to the list. The list of all the selected industrial by-products is given in Table 3.1. The table also includes the common abbreviations used subsequently in this report.

Table 3.1:Selected industrial by-products

Industrial by-product / Abbreviation
1 / Crystallised (or air-cooled) blast furnace slag / CBF slag
2 / Vitrified (or granulated) blast furnace slag / VBF slag
3 / Basic oxygen furnace slag / BOF slag
4 / Electric arc furnace slag / EAF slag
5 / Coal fly ash / CFA
6 / Boiler slag / BS
7 / Fly ash from lignite combustion / FALC
8 / Municipal solid waste incinerator bottom ash / MSWIBA

Concerning recycled construction waste, only crushed concrete was defined in D16 (SAMARIS, 2005) whereas two types are categorised: building demolition crushed concrete (BDCC) and road crushed concrete (RCC). In practice, it is seldom and often uneconomic for the load of processing plants to handle the two types of crushed concrete separately. Usually, all the construction waste is described, as well as processed, in one material group. Justification is given by the fact that crushed concrete from any sources is often polluted by extraneous components.

However, it is advisable to deal separately with bitumen-bound and tar-bound materials and the mineral construction waste. Therefore, the recycled material can been distinguished as listed in Table 3.2.

Table 3.2:Selected recycled materials

Recycled materials / Abbreviation
1 / Crushed mineral construction waste / CMCW
2 / Reclaimed asphalt / RA
3 / Tar bound reclaimed road material / TB

For better understanding, the selected materials will be described together with the potential applications of each material in road structure according to D16 (SAMARIS, 2005), see Figure3.1. The description of the applications is a summary from D16. For detailed information, it is useful to look directly at D16.

Figure 3.1:The typical road structure

The different sections of the road structure can be described according to their technical functions as follows:

  • Section 1Surface course
  • Section 2Base layer
  • Section 3Sub-base
  • Section 4Subgrade
  • Section 5Shoulders, landscaping and embankments

3.2Assessment procedure of selected industrial by-products

3.2.1Blast furnace slag

3.2.1.1General

Blast furnace slag is a by-product of the manufacture of iron by chemical reduction in a blast furnace. It is formed in a continuous process by the fusion of limestone (and/or dolomite) and other fluxes with the residues from the carbon source (coke) and non-metallic components of the iron ore. Blast furnace slag is produced at temperatures around 1500 °C. Depending on the way of cooling it can be distinguished between crystallised air-cooled blast furnace slag and glassy granulated (vitrified) blast furnace slag (REACH, 2003).

3.2.1.2Crystallized Blast Furnace slag (CBF slag)

The essential chemical constituents of CBF slag are listed in Table 3.3.

Table 3.3:Essential chemical constituents of crystallised blast furnace slag (REACH, 2003)

Constituent / % by mass / Constituent / % by mass
CaO / 33 – 42 / MnO / 0,1 – 1,0
SiO2 / 33 – 40 / K2O / 0,3 – 0,9
MgO / 7 – 14 / Na2O / 0,1 – 0,8
Al2O3 / 9 – 15 / Stot. / 1,0 – 1.5
Fetot. / 0,1 – 0,7

Crystallised blast furnace slag can be used:

  • in surface courses, often without covering but, in some countries, with a cover against erosion (Section 1).
  • in all base layers, unbound and bound (Section 2).
  • in sub-bases, unbound and bound(Section3).
  • for subgrade (Section 4).
  • for shoulders, landscaping and embankment, in some countries with cover (Section 5).
3.2.1.3Vitrified Blast Furnace slag (VBF slag)

The essential chemical constituents of VBF slag are the same as shown in Table 3.3.