Volume 7

Pavement Design and Maintenance

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Volume 7 - Pavement Design & Maintenance

Section 1:

Preamble

Section 2:

Pavement Design and Construction

Section 3:

Pavement Maintenance Assessment

S ti 4 Section 4:

P Pavement t Maintenance M i t Methods M th d

Section 5:

Surfacing g and Surfacing g Materials

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Volume 7 - Pavement Design & Maintenance

Section 1:

Preamble

HD23 General information Glossary and structure of volume 7

HD35 Technical Information March 1995 Primarily concerned with recycling of materials in road pavement

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Volume 7 - Pavement Design & Maintenance Section 2:

Pavement Design and Construction

HD24 Traffic Assessment Feb 1996 HD25 Foundations Jan J 1994 HD26 Pavement Design Aug 2001 HD27 Pavement Construction Methods HD39 Footway Design

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Volume 7 - Pavement Design & Maintenance

Section 3:

Pavement Maintenance Assessment

3 Standards - not applicable to Ireland

See NRA Interim Guidelines for Pavement and Maintenance Works

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Volume 7 - Pavement Design & Maintenance Section 4:

Pavement Maintenance Methods

2 Standards and 1 Scottish Memo - not applicable to Ireland

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Volume 7 - Pavement Design & Maintenance

Section 5:

Surfacing and Surfacing Materials

HD36 Surfacing Materials for New and Maintenance Construction February 1999 HD37 Bituminous Surfacing Materials and Techniques HD38 Concrete Surfacing and Material

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Volume 7 7,, Section 2, Part 1 HD 24 - Traffic Assessment New NRA Addendum to HD24/06 imminent Note both HD24/96 and HD24 /06 are based on UK traffic growth predictions,, which are not applicable to Ireland predictions Standard St d d method th d in i HD24/96 iis nott used d in i IIreland l d Currently use the Structural Assessment and Maintenance Method outlined in Chapter 3 of HD24/94 HD24/06 combines Chapters 2&3 but introduces different wear factors for New Construction which are not to be used in Ireland. Heavy Vehicle Classifications Classifications:: 3 Axle Artics moved to OGV2

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Volume 7 7,, Section 2, Part 1 HD 24 - Traffic Assessment

Heavy Vehicle Classifications Buses and Coaches = PSV 2 Axle Rigid = OGV1 3 Axle Rigid = OGV1 3 Axle Artic = OGV1 => OGV2 4 Axle Rigid = OGV2 4 Axle Artic = OGV2 5 Axle ++

= OGV2

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Volume 7 7,, Section 2, Part 1 HD 24 - Traffic Assessment VEHICLE CLASSIFICATIONS Threshold for 2 axle rigid HCV: double tyre rear axle Calculation of Design Traffic Loading requires minimum of OGV1 and OGV2 proportions in traffic surveys and predictions

WEAR FACTORS OGV1 WF = 0.6

OGV2 WF = 3.0

Note these are Maintenance Factors in HD24/06 New Figure 2.1 in HD24/06 dictates the minimum proportion of OGV2 vehicles to be assumed

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Volume 7 7,, Section 2, Part 1 HD 24 - Traffic Assessment

Figure 2.1 – Minimum Percentage of OGV2 Class V hi l for Vehicles f New N Construction

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Volume 7 7,, Section 2, Part 1 HD 24 - Traffic Assessment STEP 1 – Calculate Design Traffic Loading T ffi P Traffic Predictions di ti should h ld b be agreed d with ith NRA iin accordance d with ith th the NRA Project Appraisal Guidelines Growth rates currently being used in NRA PAG vary with time BUT Chart in HD24 can only be used to obtain growth factors where a constant growth rate is assumed over the life of the pavement

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Volume 7 - HD24 Traffic Assessment

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Volume 7 7,, Section 2, Part 1 HD 24 - Traffic Assessment Design Traffic Loading – For Constant Growth Rate Old Table 3.1/ new Table 2.4 - Wear factors for each vehicle category - Weighted Annual traffic derived by multiplying the opening year flow by the growth factor and wear factor - DESIGN TRAFFIC is the sum of the Weighted Annual Traffic for each vehicle category multiplied by design period For multi lane roads multipl multiplyy by the % traffic in the left hand lane – old ld Fi Figure 3 3.3/new 3/ Fi Figure 2 2.4 4 – left lane pavement applies across full width

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Volume 7 - HD24 Traffic Assessment

T bl 2 Table 2.4 4 Calculation of Design Traffic Assuming a constant growth rate

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Volume 7 7,, Section 2, Part 1 HD 24 - Traffic Assessment Design Traffic Loading – For Variable Growth Rate New Table 2.4a 2.4a in NRA Addendum - Wear factors for each vehicle category - Weighted Lifetime traffic derived by summing the predicted traffic over the design period multiplied by the wear factor - Weighted lifetime traffic = - DESIGN TRAFFIC is the sum of the Weighted g Lifetime Traffic for each vehicle category For multi lane roads multipl multiplyy by the % traffic in the left hand lane

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Volume 7 - HD24 Traffic Assessment

Table 2.4a 2.4a – Table for the Calculation of Design g Traffic when Predictions for each Individual Year are available

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Volume 7 7,, Section 2, Parts 2 & 3 Pavement Design

STEP 2 - Pavement design : New NRA HD 2525-26 imminent UK HD 25 Pavement Foundations replaced by IAN 73 UK HD 26/01 Pavement Design updated to HD 26/06 NRA retaining HD25/94 and HD26/01 for Fully Flexible Pavements while adopting elements of IAN 73 and HD26/06 for Flexible Composite, Rigid Pavements and EME2

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Volume 7 7,, Section 2, Parts 2 & 3 Pavement Design UK IAN 73 Foundations - introduces four classes of foundation - defines restricted designs and performance designs NRA HD25 HD25--26 - retains design charts from HD25/94 for Foundations beneath Fully Flexible Pavements - adopts design charts for Class 2 and Class 3 Restricted Designs from IAN 73 for Foundations beneath other Pavements Performance related design NOT adopted in Ireland

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Volume 7 7,, Section 2, Parts 2 & 3 Pavement Design

Foundation for Fully Flexible Pavements

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Volume 7 7,, Section 2, Parts 2 & 3 Pavement Design 700

Capping plus sub--base sub

600

500 Thickness (m mm)

Foundation for all other types of Pavements

Capping layer thickness

400

Total foundation thickness Type B sub-base (Class 2 foundation)

300

Total foundation thickness CBGM A or B, C3/5 or C5/6 (Class 2 foundation)

200

100

Class Cl 2

0 2.5 3

4

5

6

7

8

9 10 11 12 13 14 15 20 25 30

Subgrade CBR (%)

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Volume 7 7,, Section 2, Parts 2 & 3 Pavement Design

Sub-base Subonly

500

400 Layer Thicknes ss (mm)

Foundation for all other types of Pavements

300

Granular Sub-base Type B (Class 2)

200

Cemented sub-base CBGM A or B, C3/5 or C5/6 (Class2) or C8/10 (Class3)

100

Class 2 or 3 30

20

18

16

14

12

10

8

6

4

2. 5

0

Subgrade CBR (%)

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Fully Flexible Pavement Design

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Flexible Composite Pavement Design

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Rigid Pavement Design

NRA Requires Class 3 Foundation CRCB requires min 100mm Bituminous surfacing Add 30mm if less than 1m hardstrip on left 25

EME2 Pavement Design

Stiffer Bituminous Material which p permits thinner p pavements Requires Class 3 Hydraulically Bound Foundation Will have its own design chart separated from other fully flexible pavements

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Volume 7 – HD 36 Surfacing Materials

Table 2 2.2.I 2 I (Ireland) ::- Defines Permissible surfacing options HRA, TSCS, PA, Surf Dress etc - Restricts use of all but HRA - Forthcoming revision will remove restriction on PMSMA (TSCS)

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Volume 7 – HD 36 Surfacing Materials

Table 3 3.1.I 1 I (Ireland): (Ireland):- Defines minimum PSV requirements for different road types and traffic flows - Forthcoming revision will restrict the use of High Skid Resistant Surfacing

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MCDRW Series 700

Series 700 Road Pavement - General: General:- Forthcoming g

g general revision for consistency y with European Standards

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MCDRW Series 800

Series 800 Road Pavements – Unbound, Unbound Cement and Other Hydraulically Bound Mixtures: Mixtures:- Forthcoming major revision based on MCDHW and Euro Norms - Introducing g new HBM materials for Flexible Composite p Bases and Cemented SubSub-bases

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MCDRW Series 1000

Series 1000 Road Pavement – Concrete Materials: Materials:- Forthcoming major revision based on MCDHW and Euro Norms - Deletion of CBM replaces by HBM’s HBM s in new Series 800

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