1155 Howard Robinson

7/29/2019 1155 Howard Robinson

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THE ROAD SURFACE

TREATMENTS ASSOCIATION

Surface Dressing & Micro-Surfacing

Dr Howard Robinson

Chief Executive

1www.rsta-uk.org


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Surface Dressing

Long History of Use

www.rsta-uk.org


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Performs 2 functions which relate directly to the essential

requirements in the European CPD Safety Skid Resistance

Increases macro & micro texture with minimum usage ofscare high quality aggregate

Durability Preventative Maintenance

Seals underlying surface from ingress of water and air

3

Surface Dressing

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Single Dressing

Racked-In

Double Dressing

Sandwich Dressing

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Surface Dressingtechniques

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Carriageways

Footways

Cycleways

Car parks

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Surface DressingApplications

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Treatment composition kg/m2

Material SingleDressing

DoubleDressing

40mmAsphalt

Surfacing

Binder 1.0 1.5 6.0

Aggregate 12.0 21.0 93.0

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Finite Resource ConsumptionFinite Resource Consumption


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Comparative Costs and Life

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Type Application /m2

+/10%Expected

Life

years

6mmSingleSurfaceDressing Estateroads,ruralareas 1.50 7 10

10&6mmRackedInDressing Urbanroads,quieter 1.80 7 10

14&6mmDouble

Surface

Dressing (relativelynew)Busy

urban

roads,

higher

stress,gradient,bend2.20 7

10

Prepatchingadditionalcost Rural,urbanroads 1.00 1.50 n/a

MicroAsphalt 14mm MainlyUrbanlocations 3.00 7 12

Microasphalt

+regulating

+

ironworksraisedMainly

Urban

locations 3.50

4.00 7

12

HighFrictionSurfacing Highstressareas 9 12 5 10

Retexturing bushhammer Anywhere exposedaggregates

2 3 3 5

GilsonitePreservative Anywhere 0.8

1 3

5

AsphaltReinforcement

Geocomposites/Geotextiles

Urban,trunkroads 5 8 Increaseslifeby

factorof4


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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Years

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Years

Overa l l

condit ion

Overa l l

condit ion

G o o d

Good

Poor

Poor

Sur face d ress ing

Sur face dress ing

De fects visible

Patch ing

Reconst ruct ion

Sur face d ress ingSur face dress ing

Source: Asphalt Surfacings, Steven St John

8

Surface DressingExtending time to structural maintenance

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Work ongoing at University of Nottingham to develop processmaps and capture energy data for a range of surfacetreatments that can then be fed into asPECT

Asphalt Pavement Embodied Carbon Tool

9

Carbon Footprint

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Quality ControlQuality Control


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Chipping Spread Rate Test

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Binder Spread Rate Test


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Carpet Tile Spray Bar Test


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SpecificationSpecification

SHW Clause 922SHW Clause 922

BSEN 12271BSEN 12271

PD6689PD6689


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Procurement

Method 1 Specified by end product performance - Cl 922 of SHW

Method 2 Specified by recipe - Cl 919 of SHW

Method 1 defines a product and therefore the Construction Product

Regulation applies and BSEN12271

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Clause 922

Thecontractormust...

Produceadesign

to

achieve

alevel

of

performance

e.g.

macrotextureandalsoadesignlife

InstalladressingthatmeetsrequirementsofNHSS13a

Provideaqualityplan

BecompliantwithBSEN12271

Providea2yrguarantee

Provideevidencehisspraytankerandchippingmachinecanachieve

the

desired

rate

and

accuracy

of

spread

ProduceaselfcertifiedTAIT

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BSEN 12271 EffectiveinUKfromJanuary2011

PD6689providesUKguidance

Specifiesarangeofpropertiesandcategoriestoenable appropriatelimitingvaluestobesetfora

widerangeofuses

CEMarkingcurrentlynotmandatoryinUK

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PD 6689 Constituent Materials

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Binders

UnmodifiedbindersmustconformtoBSEN13808

emulsions PMBsareproprietarymaterialsandClauses919and

922requirethesetohaveBBAHAPAScertificates BSEN

12271

includes

ameasure

of

binder

cohesion

(VialitTest)

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Modified BindersModified BindersVialit

Pendulum

Cohesion

Vialit Cohesion BS EN 13588

HA SHW Clause 939

Grades (minimum Peak Cohesion):

Super premium binder 1.4J/cm2

Premium binder 1.2J/cm2

Intermediate 1.0J/cm2

Unmodified* 0.7J/cm2

*threshold level for guidance only

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PD 6689 Aggregates

HD36adviseswhatPSVandAAVtobeusedonasitebysite

basis. The

PSV

is

required

to

ensure

the

durability

of

skiddingresistance

AggregatesusedinsurfacedressingshouldconformtoBSEN13043

Recommendationsfor

gradings

of

chippings

are

in

PD

6682

2:2009,Table4

BSEN13043alsorecommendsthat,forsurfacedressing,the

fines

content

should

be

f1(i.e.

not

more

than

1%

passing

0.063mmsieve)

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PD 6689 Performance Criteria

PerformancecategoriesinPD6689havebeenchosenfromBSEN12271:2006,Table2

TheserecommendationsrelatetheHAUCroadtypestogetherwiththedesignclassificationsfromRN39

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EN 12271:2006(E) - Table 2


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Type Approval Installation Trial (TAIT)

TAITsarethemeansbywhichaproducer

demonstratesthe

ability

to

design

and

install

agroup

orfamilyofsurfacetreatmentsmeetingtherequired

performancecharacteristics

TAITscan

also

be

used

as

the

basis

for

CE

marking

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Type Approval Installation TrialRecommended Portfolio

TAITs are the responsibility of the producer andmust be verified by a notified body

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Factory Production Control (FPC)

BSEN12271specifiesaFPCsystem aroutetoCEmarking

FPCensuresthedesignprocedureisdocumented,therelevantcontrolsand

tests

are

carried

out

at

minimum

frequency

and

records

are

kept

AllproducersaccreditedtoNHSS13amusthaveaQAsystemwhichmeetsFPCrequirementsandareaccreditedbynotifiedbodies

TheSectorSchemeisarequirementoftheSHWandrequiresproducers

todemonstrate

the

competence

of

their

workforce

ThereisascheduleofsuppliersaccreditedtoNHSS13amaintainedbyLantra

Theattestationofconformityis2+

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Surface Dressing Design Guide


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SurfaceTemperatureCategory

RoadHardness

Traffic

Geometry

Chippingproperties

Design Input Data

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Surface Temperature Category

Table 7.2.1 - Approximate Surface Temperature Categories

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Road Hardness Category

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Road Hardness Category

very soft

soft

normal

hard

very hard0

2

4

6

8

10

12

14

16

18

20

22

10 15 20 25 30 35 40

Road surface temperature (C)

Probepenetration

(mm)

Figure 7.2.2 Hardness categories from depth of penetration and roadsurface temperature for Different Surface Temperature Categories

Category B


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Traffic

Table 7.2.3 Traffic Categories

Categories converted from msa to cv/l/d assuming a

growth rate of 2% over the design life.

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Geometrics

Gradients

Bends

Junction and Crossings

= STRESS

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Chipping Properties

PSV refer to HD36/06 or Figure 7.3.1.

AAV Not greater than 14

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Other Data Required

General Surface Condition

Season

Shade

Local Traffic

Noise

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Season

Figure 7.3.2 Surface Dressing Season


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Tree Shade

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Noise

Increasing texture depth

Increas

ing

noise

(dBA

)

6mm

10/6mm

10mm

14/6mm

14mm

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Designing the Dressing

Site Suitability

Sections within the Site

Choosing the Dressing type and Binders

Using the Design Proforma

Selecting the Rate of Spread

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Site Suitability

Figure 8.1 - Effect of Existing Road Surface Characteristics on

Achievable Performance Levels


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Choosing The Right Dressing

Figure 8.3a

Selection of Type of SurfaceDressing for Lightly-Trafficked

Sites

Binder Rate of Spread Table


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Binder Rate of Spread - Table

9.2.2

Racked In Dressing


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Relatively low cost and high productivity

Extends road life and delays major maintenance spend

Reduced traffic management costs and road user costs

Efficient use of aggregates/binder and minimal waste Up to 10 year life if properly designed and executed

A strategic option for de-carbonising roads

Can help to prevent potholing

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Surface DressingBenefits


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Better,tougherbinders=betterchipretention

Lowtemperatureemulsions(undertrial)

Betteremulsion

break

control

Bettermobileplant improvedspraying/spreadingaccuracy

Closerattentiontoachievinggoodcompaction

Closerliaisonwithhighwayauthorities

Improvedaftercare

BettertrainedoperativeswithCSCScards(SectorScheme13a)

Surface DressingInnovation

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MicroMicro--SurfacingSurfacing

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Micro-Surfacing

Apolymermodifiedcoldpavedasphalt

Thickness6to15mm

Uses

rutfilling/levellingcourse

sealing

fillingpotholes

correctsravelling/bleeding

improvesskidresistance(highervolumeroads)

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Micro-Asphalt Description Slurrysurfacingintroducedinthelate1950s Primarilyusedasapreservativetreatmentforairfield

runwaystypical

aggregate

size

for

slurry

surfacing

03mm

Slurrysurfacingnowmorewidelyknownasmicroasphaltsormicrosurfacingwithtypically06mmaggregates

Microasphaltisamixtureof:

Aggregates(coarse

and

fine)

PMBemulsion

Water

Cementorhydratedlime Possiblyfibres

Chemicalbreaking agent

Theblendofmaterialsisbatchedinsituandlaidbyapurposebuiltselfpropelledmicroasphaltpaver

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Slurry Seal and Micro-Asphalt Footwayslurrysealismechanicallymixedandhandapplied

usingabrushtoprovidesurfacetexture.Nonpolymer

modifiedbitumen

emulsion

and

aggregate

sizes

of

03mm

Thincarriagewayandairfieldslurrysealisusuallylaidupto5mmthickusinga03mmaggregateandnonpolymerbitumenemulsion.Laidmechanicallyandissuitableforurbanareasandairfieldtaxiways

Microasphalts firstlayerregulatesandreprofilestheexistingpavement secondlayerprovidesadensesurfacewithgoodtexturedepthand

wetskiddingresistance.

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SLURRY / MICROSURFACING


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SLURRY / MICROSURFACING


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Composition

Aggregates

Mineralfiller

Water

Bitumenemulsion

Fieldcontrol

additive

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Aggregate selection

Strong,durable

100%crushedparticles

Typeof

rock

Reactivityoffines critical!

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Aggregate Gradation

Sieve size

mm

Slurry Micro-

surfacing5.0 100 100 70-90

2.36 95-100 75-100 45-70

1.18 70-95 55-90 28-50.600 55-75 35-70 19-34

.300 30-50 20-45 12-25

.075 5-15 5-15 5-15

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Mi l Fill


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Mineral Fillers

Portland

cement

Hydratedlime

Modifyflow&settingcharacteristics

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Bitumen Emulsion Selection


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Bitumen Emulsion Selection

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P l


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Polymer

Purposes

reducestemperature

susceptibility

improvesstiffness

Types

latex(liquid)

solids

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Field Control Additi e


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Field Control Additive

Affectsbreak

time

temperature&aggregatereactivity

Typeand

amount

amines(0.1%)

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Surface Curing


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Surface Curing

Mixtime

time

remaining

fluid

(30

180

s) Settime

expulsionofclearwater&initialdevelopment

ofcohesion

Traffictime

sufficientcohesionfortraffic(20minto4hrs)

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Mix Design Criteria


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Mix Design Criteria

Mixingtests

Cohesiontest

Testsfor

binder

content

Performancerelatedtests

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Mixing & Cohesion Tests


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Mixing & Cohesion Tests

Mixtime&settime

Handmixed

for

30s

Partpouredout. Clearwaterexuded settime

Partstirreduntilstiff mixtime

Cohesiontest

Rolledinto

ball

&

dropped

on

floor

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Tests For Binder Content


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Tests For Binder Content

Wettrack

abrasion

(WTAT)

BS434aggregatetest(max500g/m)

Loadedwheeltest

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Site Selection Client Side


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Site Selection Client Side

Highwayclientslooktomicrosurfacingtoimprove:

Appearance coveringsurfacedefectsProfiling regulationofthesurfaceSkidResistance replacescontactsurface

SubsurfaceProtection

sealing

the

road

against

water

ingress

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A Potential Micro Surfacing Site


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A Potential Micro-Surfacing Site

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Micro Asphalt Paver


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Micro-Asphalt Paver

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AGGREGATE


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WATER

BITUMEN

SPREADER BOX

Computer Controlled Batching


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Computer Controlled Batching

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Applied through the Spreader


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Laying box

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Compaction using a Pneumatic Tyre


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Roller (PTR)

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After Care


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After Care

Readyfortrafficafter20minutes

Sweepafter

24

hours

RaiseIronworknextday

Applyroadsafetymarkingsafter72hours

Removetrafficmanagementsigns

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Slurry-Micro Surfacing


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Applications

Carriageways

Footways

Cycleways

Car parks

Playgrounds

Airfield runways

Reservations and Islands

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Benefits


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Benefits

Restorationofinstantaneousskidding

resistanceand

texture

depth

levels

Quickinstallation,withminimumdisruptiontotrafficflows

Environmentallyadvantageous

with

little

or

notoxicemissionsandnoheatenergyrequired

Financial

cost

benefits

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BSEN 12273 Micro-Surfacing


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BSEN 12273 Micro Surfacing

UK guidance contained in PD 6689

BSEN 12273 will be implemented in UK inJanuary 2011

By that time all contractors must have in place:

BSEN ISO 9001 QA systems, FPC, TAITs UK specification controlled by SHW Cl.918

contractors must be compliant with Sector

Scheme 13b

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Specification Requirements


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Specification Requirements

Aggregates to BS EN 13043

Binders to BS EN 13808 Cationic BitumenEmulsions

Mix design declared by producer

1 year after installation:

visual assessment of defects

surface macro-texture

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BS EN 12274 Test Methods


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1. Sampling

2. Residualbindercontent

3. Consistency mix

design

4. Cohesionofmix mixdesign

5. Wearing

(wet

track

abrasion)

mix

design6. Rateofapplication

7. Shakingabrasion(binder/aggregateaffinity)

mixdesign

8. Visualassessment

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Clause 918


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Contractordesign

RegistrationtoSectorScheme13B TAITtoBSEN12273 Aggregate

min.

PSV

&

max.

AAV

(FI20 omitted)

Performancerequirements

Assessmentofdefects&macrotexture

2year

guarantee

(macrotexture

initially,

1&

2years)

Normally1yearfornontrunkroads

Specifieshowtoexecutetheworks

BBAHAPAScertificationformodifiedbindernolongerrequired

Bondcoatspecified

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Notes for Guidance on Clause 918


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Clause 942 thin surfacing applicable to

micro-surfacing for roads carrying > 250cv/l/d or allowing speeds > 60 mph

Categories given for visual assessment of

defects from lightly trafficked roads (Cat. 1) to dual

carriageways (Cat. 4)

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Performance Requirements


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Requirement Unit Category

0 1 2 3P1 bleeding, etc. % NPD 8 2 0.5

P2 delamination,aggregate loss, etc.

% NPD 8 2 0.5

Macrotexture mm NPD 0.2 0.4 0.6

Noise (macrotexture) mm Declared maximum

Constituents

Binder cohesion

Aggregate PSVAggregate micro-Deval

J/cmDeclared class/category

(AAV in UK)

Slurry type Defined by maximum aggregatesize & binder type

Guidance


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Design Manual for Roads and Bridges

Volume 7 Section 5 Part 2 HD37/99

SHW Series 900

Clause 918 - Slurry Surfacing

Clause 919 - Surface Dressing Recipe

Clause 922 - Surface Dressing Performance

Clause 927 - Micro-surfacing

EN 12271 Surface Dressing (FPC + test methods)

EN 12273 Slurry-Micro Surfacing (FPC + test methods)

PD6689: 2009 Surface Treatments

NHSS 13a Surface Dressing and 13b Slurry-Micro Surfacing

Road Note 39 and RSDA Code of Practice

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THANKS FOR LISTENING!

Visit

www.rsta

uk.org for

our

calendaroftrainingcourses

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1155 Howard Robinson

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