Use of Volume 7 (Including Erratum No. 1, dated January 2016)

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Use of Volume 7 (Including

Erratum No. 1, dated

January 2016)

GE-PAV-01006

March 2015

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About TII

Transport Infrastructure Ireland (TII) is responsible for managing and improving the country’s

national road and light rail networks.

About TII Publications

TII maintains an online suite of technical publications, which is managed through the TII

Publications website. The contents of TII Publications is clearly split into ‘Standards’ and

‘Technical’ documentation. All documentation for implementation on TII schemes is collectively

referred to as TII Publications (Standards), and all other documentation within the system is

collectively referred to as TII Publications (Technical). This system replaces the NRA Design

Manual for Roads and Bridges (NRA DMRB) and the NRA Manual of Contract Documents for

Road Works (NRA MCDRW).

Document Attributes

Each document within TII Publications has a range of attributes associated with it, which allows

for efficient access and retrieval of the document from the website. These attributes are also

contained on the inside cover of each current document, for reference. For migration of

documents from the NRA and RPA to the new system, each current document was assigned with

new outer front and rear covers. Apart from the covers, and inside cover pages, the documents

contain the same information as previously within the NRA or RPA systems, including historical

references such as those contained within NRA DMRB and NRA MCDRW.

Document Attributes

TII Publication Title Use of Volume 7 (Including Erratum No. 1, dated January 2016)

TII Publication

Number

GE‐PAV‐01006

Activity

General (GE)

Document Set

Standards

Stream

Pavement (PAV)

Publication Date

March 2015

Document

Number

01006

Historical

Reference

NRA HD 23

NRA DMRB and MCDRW References

For all documents that existed within the NRA DMRB or the NRA MCDRW prior to the launch of

TII Publications, the NRA document reference used previously is listed above under ‘historical

reference’. The TII Publication Number also shown above now supersedes this historical

reference. All historical references within this document are deemed to be replaced by the TII

Publication Number. For the equivalent TII Publication Number for all other historical

references contained within this document, please refer to the TII Publications website.

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Volume 7: Pavement Design & Maintenance

Use of Volume 7

(including Erratum No. 1, dated January 2016)

Volume 7 Section 1

Part 1 NRA HD 23/15

March 2015

St. Martin’s House, Waterloo Road, Dublin 4 Tel: +353 1 660 2511 Fax +353 1 668 0009

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Summary:

This Standard provides details regarding implementation of NRA DMRB Volume 7 and it provides an introduction to the whole volume.

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NRA DESIGN MANUAL FOR ROADS AND BRIDGES

VOLUME 7

Pavement Design and

Maintenance

SECTION 1 Preamble

PART 1 NRA HD 23/15

Use of Volume 7 (including Erratum No. 1,

dated January 2016)

Contents Chapter 1. Introduction 2. Background 3. Use of Volume 7 4. Glossary of Terms 5. Enquiries Erratum No. 1

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1. INTRODUCTION

General

1.1 This Part is an introduction to the whole Volume.

1.2 Volume 7 of the NRA Design Manual for Roads and Bridges (NRA DMRB) consists of a series of linked documents. Table 3.1 in this Part gives a full list of the documents and a clear chart of the contents of each Part. Changes to Volume 7 are always in hand, Table 3.1 will not necessarily include all the latest amendments.

Implementation

1.3 This Part of Volume 7 of the (NRA DMRB) is provided for general information. Each Part of Volume 7 should be consulted for the relevant Implementation Clause.

1.4 The use of Volume 7 is mandatory for National Roads including motorways. With regard to pavement assessment and maintenance, it should be read in conjunction with the National Roads Authority’s maintenance instructions.

Mutual Recognition

1.5 Where Parts of Volume 7 give the National Roads Authority’s requirements for products, they make provision for the acceptance of equivalent products from other member states of the European Community. Reference should be made to the statement in each Part concerned.

Miscellaneous

1.6 Volume 7 does not deal with seasonal or routine maintenance, safety aspects other than skidding resistance, or specialist aspects such as the surfacing of bridge decks. For advice on these aspects reference should be made to the National Roads Authority.

1.7 Frequent references are made the following documents from the NRA Manual of Contract Documents for Road Works (NRA MCDRW):

a) Volume 1: Specification for Road Works.

b) Volume 2: Notes for Guidance on the Specification for Road Works. c) Volume 4: Road Construction Details.

1.8 References are made in the text to other documents by author and date except for Irish and British Standards, TRL Reports and National Roads Authority Publications, which are referred to by number (or name) and date. A full list of References is included in each Part.

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National Roads Authority Volume 7 Section 1 Design Manual for Roads and Bridges Part 1 NRA HD 23/15 (including Erratum No. 1)

2. BACKGROUND

2.1 Current Irish practice in pavement design and maintenance has developed from a combination of practical experience, laboratory research and full-scale road trials. The research has been carried out over a number of years by the Transport Research Laboratory (TRL), and internally with the assistance of other research contracts.

2.2 TRL Report LR 1132 (1984) provides details of UK research findings in connection with the design and performance of flexible pavements. The report makes use of the results of full-scale road experiments and uses analytical techniques to rationalise and extend the data. Many of the recommendations have since been adopted by the National Roads Authority.

2.3 TRL Report RR 87 (1987) provides comparable findings in connection with rigid pavements and many of the recommendations have also been adopted by the National Roads Authority.

2.4 Significant developments have also taken place in other countries, particularly in connection with the analytical or mechanistic approach to design. This is based on the traditional structural design philosophy, which requires an understanding of material behaviour under load and an appropriate theoretical analysis of the design problem.

Pavement Components

2.5 Figure 2.1 illustrates two typical cross-sections of road pavements. The terms used, together with others used in Volume 7 are defined in Chapter 4, the Glossary of Terms.

2.6 The underlying subgrade soil (cut or fill), capping (if used) and subbase comprises the Foundation, the platform upon which the more expensive and structurally significant layers are placed. This platform is designed to be of a certain minimum standard quality whatever the underlying soil condition. It is not a drainage layer although it does itself require to be adequately drained since it is never totally impermeable.

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2.7 The Base is the main structural layer of the pavement, required to distribute the applied traffic loading so that the underlying materials are not overstressed. It must be able to sustain the stresses and strains generated within itself without excessive or rapid deterioration of any kind.

2.8 The function of the Surfacing is to enable good ride quality to be combined with the appropriate friction to provide resistance to skidding and to resist crack propagation. For this, texture and durability under traffic are required. In the case of concrete roads, the surfacing and base are combined to form a single layer.

Pavement Types

2.9 Four different types of pavement are defined by the National Roads Authority.

a) Flexible: The surfacing and base materials are bound with bituminous binder.

b) Flexible Composite: The surfacing and upper base (if used) are bound with bituminous binder on a base or lower base of cement bound material.

c) Rigid: Pavement quality concrete is used for the combined surfacing and base. The concrete can be:-

(i) Jointed unreinforced (URC) (ii) Jointed reinforced (JRC)

(iii) Continuously reinforced (CRCP)

d) Rigid Composite: Continuously reinforced concrete base (CRCR) with bituminous surfacing.

Pavement Performance

2.10 Pavements do not fail suddenly but gradually deteriorate in serviceability to a terminal level which may be defined as failure. The rate of deterioration often accelerates as failure is approached. This is represented by an unacceptable degree of rutting, general unevenness, cracking, crazing etc. In the case of the surfacing, loss of friction can be equivalent to failure.

2.11 Some pavements, with thicker bound layers constructed on a good foundation, maintain their strength or become stronger over time, rather than gradually weakening with trafficking. Such pavements, built above a threshold strength, will have a very long structural service life, provided that distress, in the form of cracks and ruts appearing at the surface, is treated before it begins to affect the structural integrity of the road. These are referred to as long-life pavements.

2.12 It is good practice and the National Roads Authority’s intention to ensure that major maintenance or strengthening of the pavement takes place at a point such that the structural contribution of the existing pavement layers is largely retained.

2.13 To monitor the performance of the Network’s pavements, the National Roads Authority maintains and manages the NRA Pavement Asset Management System. This requires the use of a number of assessment methods including automated road surveys. These surveys include measurement of the in-service road surface friction using a SCRIM machine. In addition FWD surveys, coring and trial pits, visual condition surveys, etc. are conducted. In this way the appropriate timing can be chosen for the various necessary maintenance processes which all pavements eventually require.

Maintenance

2.14 Clearly any of the three main components of a pavement (Foundation, Base, and Surfacing) can deteriorate, leading to a reduction in the quality of performance of the overall structure. Depending upon the mode of deterioration, deduced from the various pavement assessment processes, maintenance measures ranging from surface treatment through to total reconstruction may be necessary.

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2.15 Whichever type of maintenance measure is to be adopted, it is always of the utmost importance that the correct procedures are followed to render the repair/resurfacing/overlay/strengthening as effective and long-lasting as possible

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3. USE OF VOLUME 7

3.1 The order of the section in Volume 7 is generally based on the life cycle of a road pavement, i.e., design, construction, assessment then maintenance (see Table 3.1). This starts with consideration of the cumulative traffic loading which the pavement is required to carry, followed by the design of the foundation, the base or main structural component and the surfacing. There is then a need to assess the behaviour in service and to design and carry out appropriate maintenance. It must, however, be emphasised that there is interaction between the components and that they cannot always be dealt with in isolation. The following is a brief outline of the contents of each of the sections and parts.

Section 1: Preamble

3.2 Part 1 is the general introduction to Volume 7. Section 2: Pavement Design and Construction

3.3 Part 1 describes the calculation of design traffic for both new roads and maintenance. It also covers the

calculation of past traffic, needed in pavement assessment analysis.

3.4 Part 2A gives details for the design of road pavements and foundations and of tests used for the

assessment of existing subgrade and subbase materials.

3.5 Part 5 sets out the requirements and advice for new footways constructed from materials that are subject

to a range of pedestrian traffic and some overrun by vehicular traffic.

3.6 Part 6 provides a manual for the design of road pavements using bituminous mixtures, surface

treatments and miscellaneous products and processes.

Section 3: Pavement Maintenance Assessment and Renewal

3.7 Part 1 describes the management provisions to maintain appropriate levels of road surface friction on

National Roads.

3.8 Part 3 covers the requirements for identification and approval of pavement asset repair and renewal

schemes.

3.9 Part 4 describes the assessment of existing pavements and the development of asset repair and renewal

proposals.

Section 5: Surfacing and Surfacing Materials

3.10 Part 1 gives the requirements for surfacing materials for new and maintenance construction. 3.11 Part 2 details the various bituminous surfacing materials and processes that are available.

Section 6: Product Approval

3.12 Part 1 sets out requirements and advice for the approval of specific products/systems that are not covered by a harmonised technical specification.

Notes to Sections 1 - 6

3.13 For advice on the conservation and the use of secondary and recycled materials contact NRA Network Management section.

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3.14 1_{Revisions to the NRA Manual for Contract Documents Volume 1, Specification for Road Works, Series}

900 has precluded the use of certain materials, including EME2 material. For advice on the use of EME2 material contact NRA Network Management section.

3.15 For advice on pavement construction methods involving widening, rigid concrete pavements, concrete surfacing contact NRA Network Management section.

Flow Charts

3.16 Figure 3.1 is a flowchart which is intended to show the interrelations which exist between the section and parts in Volume 7.

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PART 1 NRA HD 23 Use of Volume 7 1. Introduction 2. Background 3. Use of Volume 7 4. Glossary of Terms 5. Principal Abbreviations 6. Enquiries

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SECTION 2. Pavement Design and Construction

PART 1

NRA HD 24 Traffic Assessment

PART 2A

NRA HD 25-26 Pavement and Foundation

Design PART 5 NRA HD 39 Footway Design PART 6 NRA HD 300 Design of Bituminous Mixtures, Surface Treatments,

and Miscellaneous Products and Processes

1. Introduction 1. Introduction 1. Introduction 1. Introduction

2. Calculation of Design

Traffic

2. Standard Designs 2. Design Considerations 2. Bituminous Mixtures

3. References and

Bibliography

3. General Foundation

Design

3. Structural Design 3. Microsurfacing

4. Enquiries 4. Flexible Pavement

Design

4. Materials 4. Surface Dressing

5. Flexible Composite

Pavement Design

5. Reference and Bibliography

5. High Friction Surfacing

6. Rigid Pavement Design 6. Enquiries 6. Low Energy Bound

Mixtures

7. EME2 Pavement Design 7. Geotextiles and

Geotextile-related Products

8. Bound Materials 8. Retexturing

9. Alternative Design

Procedures

9. Permanent Repair Material

Systems and Localised Repair Material Systems

10. References 10. Emergency Repair

Material Systems 11. Enquiries 11. References 12. Enquiries2 Annex A. Specification for 45% Type F Asphalt B. Specification of Bedding Sand and Jointing Material for Small Element Paving C. Compaction Specification D. Compaction by Method Specification E. Worked Examples

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SECTION 3. Pavement Maintenance Assessment and Renewal

PART 1

NRA HD 28

Management of Skid Resistance

PART 3

NRA HD 30

3_{Pavement Asset Repair and Renewal –}

Scheme Approval Procedure

PART 4

NRA HD 31

Pavement Assessment, Repair and Renewal Principles

1. Introduction 1. Introduction 1. Introduction

2. Operation 2. Pavement Asset Repair and

Renewal Scheme Approval Process

2. Review of Data from the NRA

Pavement Asset Management System

3. Measurement of Skid Resistance 3. Selection of PARR Schemes 3. Visual Inspection Report

4. Setting the Investigatory Level 4. Data Collection 4. Scheme Level Surveys and

Investigations

5. Site Investigation 5. Pavement Asset Repair and

Renewal Proposal

5. Interpretation and Analysis of Data

6. Prioritisation of Treatment 6. Procurement 6. Pavement Surface Treatment

Options

7. Use of Warning Signs 7. Monitoring of the Pavement Repair

and Renewal Works

7. Structural Strengthening of the

Pavement

8. References 8. Close Out of PARR Schemes 8. Pavement Drainage

9. Enquiries 9. Emergency and Isolated Pavement

Repairs

9. References

10. References 10. Enquiries

11. Enquiries

Annex Appendix Appendix

1. Background Information on the

Measurement and Interpretation of Skid Resistance

A. Template for the PARR Scheme Proposal

A. NRA Pavement Asset Management System

2. SCRIM Survey of Operational

Procedures

B. Short Form PARR Proposal for Emergency and Isolated Pavement Repairs

B. Falling Weight Deflectometer Surveys and Analysis

3. Processing and Computation of

Characteristic SCRIM Coefficient

C. Templates for NRA Regional Management Consents and Approvals

C. Coring and Trial Pits

4. Site Investigation D. Templates for PARR Scheme

Close Out Information

D. Dynamic Cone Penetrometer

5. Assessment of Collision Data E. Laboratory Testing

6. Use of Different Types of Test

in Collision Investigation

F. Ground Penetrating Radar

G. Carriageway Pavement Defect Types

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SECTION 5. Surfacing and Surfacing Materials

PART 1

NRA HD 36

Surfacing Materials for New and Maintenance Construction, for Use in Ireland

PART 24

NRA HD 37

Bituminous Mixtures, Surface Treatments, and Miscellaneous Products and Processes

1. Introduction 1. Introduction

2. Surfacing Options 2. Properties of Bituminous Materials

3. Texture, Skidding Resistance and Noise 3. Bituminous Pavement Options

4. Selection of Aggregate 4. Hot Rolled Asphalt

5. References and Bibliography 5. Stone Mastic Asphalt

6. Enquiries 6. Porous Asphalt

7. Microsurfacing

8. Surface Dressing

10. Low Energy Bound Mixtures

11. Geotextiles and Geotextile Related Products and Materials

12. Retexturing of Bituminous Pavements

13. Permanent Repair Material Systems and Localised Surface Repair Systems

14. Emergency Repair Material Systems 15. References

16. Enquiries

Annex

A. Additional Testing and Monitoring of Aggregate and Surfacing Performance

B. Management of Sites where DBM Binder Course is Used as a Temporary Surfacing

SECTION 6. Product Approval

PART 1

NRA HD 301 Approval of Specific Products

1. Introduction

3. Low Energy Bound Mixtures

4. Retexturing

5. Permanent Repair Material Systems and Localised Repair Material Systems

6. References

7. Enquiries

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Figure 3.1: Use of Volume 7 Section 2, Part 1 Traffic Assessment Section 5, Parts 1 & 2 Surfacing and Surfacing Materials Section 2 Parts 2A & 6 Pavement Design Section 6, Part 1 Product Approval Section 3, Parts 3 and 4 Pavement Repair and

Renewal Section 3 Parts 1 Skidding Resistance Section 1, Part 1 Use of Volume 7 Section 2, Parts 2A Foundation Design Section 2, Part 5 Footway Design Section 5, Parts 1 & 2 Surfacing and Surfacing Materials

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4. GLOSSARY OF TERMS

Base: Main structural layer of pavement; placed above subbase.

Capping: A subgrade improvement layer, protecting the subgrade from damage. Chainage: Distance along a carriageway from a reference point.

Crack and Seat: Process whereby a failed concrete pavement is broken into relatively small slabs and

compacted prior to overlaying.

Deflection: The recoverable movement of the surface of a pavement under a transient load.

Deformation: The irreversible movement/compression of pavement layers, leading to rutting and settlement. Design Period: The number of years for which a pavement is designed.

Design Traffic: The predicted traffic occurring over the design period: usually expressed in terms of millions

of standard axles (msa).

Elastic Modulus: A measure of the material stiffness properties.

Fatigue: The formation of cracks in pavement materials under repeated loading. Flexible: Bituminous base and surfacing.

Flexible Composite: Cement bound base, bituminous surfacing. Formation: Level upon which sub-base is placed.

Foundation: All materials up to the top of subbase.

Growth Factor: The proportional increase/decrease between the average ‘whole life’ traffic flow on a road

and the flow at opening (or present flow).

Growth Rate: The annual percentage increase in vehicle flow.

Inlay: The replacement of some of the layers of an existing pavement with new materials i.e., a form of partial

reconstruction to existing or to different levels.

Macrotexture: The height above a road surface of the aggregate chipping or the depth of texture below the

road surface that is visible as roughness of a surfacing material, which enables drainage of water, etc.

Megatexture: The degree of smoothness of the surface.

Microtexture: The roughness of the surface aggregate associated with its microscopic properties of the surface

which enable it to develop friction and thus to provide skidding resistance.

Modulus: The ratio, stress/strain.

Overlay: The placement of new material directly onto the surface of an existing pavement using inlay of

50-100mm, overlay up to 50-100mm, base / binder patching and associated pre-treatments.

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Reconstruction: The replacement of some or all layers of an existing pavement with new (or recycled)

materials.

Rigid: Concrete base and surfacing.

Rigid Composite: Concrete base, bituminous surfacing. Standard Axle: An axle with an 80kN total force.

Stiffness Modulus: The equivalent of elastic modulus but for materials whose stiffness varies (e.g., with

temperature, stress state, etc.)

Strengthening: Renewal of the pavement structure to correct defects on pavement layers beneath the

pavement surface and within the pavement foundations using inlay of 100-200mm and overlay up to 200 mm.

Subbase: A platform layer upon which the main structure of a pavement may be laid. Subformation: Top of subgrade level if a capping is used.

Subgrade: Soil underlying a pavement (may be fill material).

Surface Dressing: A single/double/triple layer of aggregate combined with one or more layers of binder to

form a running surface.

Surfacing: Upper layers designed to carry traffic directly.

Vehicle Category: Description of vehicle by general weight/damaging power, e.g., ‘other goods vehicle

category 2 (OGV2)’.

Vehicle Class: Description of vehicle by type and number of axles e.g., ‘3 axle Articulated’ or ‘Buses and

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5. ENQUIRIES

5.1 All technical enquiries or comments on this document, or any of the documents listed as forming part of the NRA DMRB, should be sent by e-mail to [email protected], addressed to the following:

Head of Network Management, Engineering Standards & Research National Roads Authority

St Martin’s House Waterloo Road Dublin 4

………...

Pat Maher

Head of Network Management, Engineering Standards & Research

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National Roads Authority

Design Manual for Roads and Bridges

(NRA DMRB)

Erratum No. 1 (January 2016) to NRA Design Manual for Roads and

Bridges Volume 7, Section 1, Part 1

NRA HD 23 – Use of Volume 7 Dated March 2015

The NRA Design Manual for Roads and Bridges (NRA DMRB) NRA HD 23 Use of Volume 7, dated March 2015 is amended as follows:-

1. Page 6, Clause 3.14

Correct typing error “Revsions” – change to Revisions 2. Page 8, Table 3.1, Section 2, Part 4

Remove the word “Annex” from the bottom of the NRA HD 300 contents. 3. Page 9, Table 3.1, Section 3, Part 3

Replace NRA HD 30 title with “Pavement Asset Repair and Renewal – Scheme Approval Procedure”. 4. Page 10, Table 3.1, Section 5, Part 2

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Parkgate Business Centre,