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Mixtures – How to Specify Them

Andy SimmsJacobs Laboratories

London Asphalt Specification ( Makes the following simpler!)

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Idealised Pavement Structure (Flexible or Flexible Composite)

Surf ace CourseBinder Course

Base

Sub Base

Capping Lay er

Sub grade

Fou

ndat

ion

Surf acing

Formation Lev el

Pav ement

Road Surf ace

Specification for Highway Works

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British Standards – pre January 2008

PRODUCT STAND ARDLAYING STANDARD

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HAPAS Certificate

HAPAS - Highway Authorities Product Approval

Scheme• New Materials including Thin Surface Course Systems• Proprietary systems, e.g. Masterpave, Axoflex, Durapave• Specified through SHW Clause 942 • Approval through BBA

• Two year guarantee

Asphalt Standards and Specifications

BS asphalt standards that you use in all contracts were changed on 1 January

All the laying standards and BS test methods also changed on 1 January.

Specification for Highway Works has also been revised (IAN101 & IAN102).

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Why? - Principles of European Standards

Harmonisation of individual countries specifications and test methods

Elimination of barriers to tradeBS EN’s have greater authority/legal standing than current BS’s

The European Standard brings compliance and conformity in to the standard

Enforcement is a trading standards issue

Asphalt Product Standards

7 standards covering the products

1 standard covering Recycled Asphalt

2 standards covering Factory Production Control (QA)

(44 Standards covering test methods)

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The EN 13108 Family of Standards - Products

BS EN 13108-1 Asphalt ConcreteBS EN 13108-2 Asphalt Concrete for Very Thin LayersBS EN 13108-3 Soft Asphalt (Nordic countries)

BS EN 13108-4 Hot Rolled Asphalt

BS EN 13108-5 Stone Mastic AsphaltBS EN 13108-6 Mastic Asphalt

BS EN 13108-7 Porous Asphalt

The European Standards for Asphalt

Properties and other parameters− categories selected from tables− Includes recipe and performance related testing

Product IdentificationAttestation of Conformity −EN 13108-20 Initial Type Testing −EN 13108-21 Factory Production Control [FPC]

what we call QACE Marking

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On request

All the key informationrequired by law

EN Standards - Important Differences from BS

ENs relate to the product….“in the back of the lorry”, but some properties are installation dependent (BS 594987)Some description changes - mixtures prefixed by an abbreviation of their type: AC, HRA, SMA − e.g. 14 SMA surf 40/60

Some test method changes e.g. Wheel tracking instead of stabilityFormalised specification of reclaimed asphalt in BSEN13108-8Changes to compliance ‘Q’ values (Operating Compliance Level)

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UK Guidance Documents

PD 6691 – the EN 13108 family of asphalt mixtures applicable to the UK

PD 6692 - the EN 12697 family of 44 standards covering the testing of asphalt mixtures.

PRODUCT STAND ARD

PD 6691:2007

PD6691 has been drafted in a format which is similar to BS 4987-1 & BS594-1.

PD6691 contains detailed guidance on EN13108 Parts 1, 4, 5 (material specific requirements), 20 & 21 (Attestation of Conformity)

PD6691 Annexes contain stand-alone example specifications for all commonly used asphalt mixtures.

Requirements for Type testing (Protocols in BS594987)

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Requirements for Type Testing

Ac Properties(Design Void Content, deformation resistance)

Performance HRA properties (voids, resistance to permanent deformation)

SMA Binder Course properties (voids, resistance to permanent deformation)

PD 6691:2007

Example Mixture Specifications

Annexes

B - Asphalt Concrete

C - Hot Rolled Asphalt (incl. Coated Chippings)

D - Stone Mastic Asphalt (Not TSCS)

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PMB

Binder Grade

Course type

Size ‘D’ mm

Asphalt type

160/220100/15070/10040/6030/4510/20

BASEBINSURF

3260/32

2050/20,60/20

1450/14

1050/10

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HRASMAAC

How to build a description

One from each line is essential

PMB 100/15070/10040/6030/45Mix type

perfdesrec

Binder gradesurf

Course type

55/14F or C

35/14F or C

30/14F or C

55/10F or C

30/10F

15/10F

0/2F or C

Stone content/size ‘D’HRA

Material type

HRA Surface Course Descriptions

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Typical Descriptions; additional UK detail

All the information goes into the designation

−AC 32 HMB base 30/45 [30/45 = pen grade ]

PSV of the aggregate can be used in the UK mixture designation - not mandatory in the EN’s

−AC 10 close surf 100/150 PSV60

−SMA 10 surf 40/60 PSV65

−HRA 35/14 F surf PMB des [ des = design mix]

PD 6691:2007 - Nomenclature.

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Some standard AC designations and binder grades

A wide choice of binder is available

Mixture Summary – HRA

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Mixture Summary – SMA

• For full document see http://www.qpa.org/downloads/asphbulletin02.pdf

What about Laying?

BS 594987: 2007 Transport, Laying & Compaction

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BS 594987

Combination of BS594-2 & BS4987-2Covers all EN 13108 asphalt mixtures found in PD 6691Min and max compacted thicknessesAccuracy of finishImproved clarity on laying, formation of joints etc.Application of Coated Chippings and Rates of SpreadMeasurement of Texture DepthCompaction Sampling and testing for assessment of compacted asphaltMixture Approval / Type testing Protocols

Specification for Highway Works

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http://www.standardsforhighways.co.uk

SHW 900 Series

IAN101/07 (revision Feb 08)• New Asphalt Standards

• Good opportunity for a “Spring Clean”

• New requirements to improve durability

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Laying asphalt for greater durability

900 Series in summary

• Clause 901 Bituminous Pavement Mixtures

• Clause 903 Placing and Compaction of Bituminous Mixtures

• Clause 920 Bond Coats, Tack Coats and Other Bituminous Sprays

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Improved clarity for Clause 901 and 903

Clause 901: Requirements for− Aggregates− Bitumen− Aim to avoid undue repetition in individual material clauses

Clause 903: Clarify the requirements with respect to laying -particularly those affecting pavement durabilityRequirement for Method Statements

Already included in Sector Scheme 16 − Compaction procedure (paving speed, paving width, number of

passe s and number of rollers) − Joint formation

Faces of all cold upstanding edges to be painted Air v oids not more than 2% above those in the main matSealant applied to top surf ace of base and binder course joints :

Bond coats - BS 594987 Tables 3 - 4

New 0.15kg/m2

Planed 0.6kg/m2

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Clause 929 Dense Base and Binder Course Macadams (Design Mixtures)

Simplified:Volumetric requirements in PD6691Job mixture approval trial mix volumetrics - details given in BS 594987 Annex CJob mixture approval trial resistance to deformation –details given in BS594987 Annex DStiffness requirement− Smin 1500MPa

Deformation resistance − WTR to BS 598-110 until EN 13697:22 data available

Clause 937 (SMA), 943 (Perf. HRA) and 952 (Deformation Resistance)

• Clause 937 selects deformation requirements from PD 6691 Table D2

• Clause 943 selects deformation requirements from PD 6691 Table C3

• Clause 952 Deformation Resistance is no longer required (incorporated into relevant Clauses: 929, 930, 937 and 943)

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Clause 942 Thin Surface Course Systems

(11/06) Surfacing Integrity - Performance Guarantee14 The Contractor shall guarantee the integrity of the surfacing and the workmanship for a period of five yearsfrom the Contract completion date, or as otherwise specified in Appendix 7/1.NFG 24 (11/06) The guarantee periods should be clearly stated as relating only to the surface course. An appropriate Special Requirement should be included in the Conditions of Contract which draws particular attention to sub-Clauses 942.14. 942.15 and 942.16. At the end of the five-year guarantee period, the surfacing should be expected to be in at least a “Moderate/Acceptable” or a better condition after discounting any faults caused by the substrate, where the surface conditions are as defined in Appendix R of TRL Report 176.

SHW Clause 942 BBA HAPAS Classes for texture depth

Do not over-specify

High speed

Medium speed

Low speed <40mph

[1.3]

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SHW Clause 921 Surface Macrotexture of Bituminous Surface Courses

Clause 953 Durability of Bituminous Mixtures –Saturation Ageing Tensile Stiffness (SATS) Test

Required for all binder course and base mixesMixture conditioned under pressure in a wet atmosphere Mixture must have retained stiffness >80%Mixtures containing 2% hydrated lime will be deemed to comply

• Mainly a problem for all granite aggregate mixtures

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We have to strive to keep up to date

Modern Surfacing