AAPA Guide to the Handling Storage Manufacture of PMB's Final Version Jan 2013.pdf

8/10/2019 AAPA Guide to the Handling Storage Manufacture of PMB's Final Version Jan 2013.pdf

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GUIDE TO THE MANUFACTURE, STORAGE ANDHANDLING OF POLYMER MODIFIED BINDERS

DisclaimerAlthough the information contained in this booklet is believed to be fundamentally correct and current at time of printing, the Australian AsphaltPavement Association does not accept any contractual, tortious or other form of liability for its contents or any consequences arising from its use.

GUIDE TO THE MANUFACTURE, STORAGE AND HANDLING OF POLYMER MODIFIED BINDERS

Foreword

The Australian Asphalt Pavement Association (AAPA) hasprepared this guide as an aid to promoting best practice inthe manufacture, storage, transport, handling and applicationof polymer modied binders. This document replaces theprevious version entitled Code of Practice: Manufacture,Storage and Handling of Polymer Modied Binders, which waspublished in June 2004.

A signicant difference between Polymer Modied Binders(PMBs) and conventional bitumen is the need for additionalcare in handling to ensure that the effectiveness of the polymeror rubber crumb is not reduced by overheating, contamination,or other degradation during storage and transport.

Procedures contained in this guide are intended to provideassurance to end users of consistent quality of hot PMBmaterials produced in a controlled manufacturing environment.Issues relating specically to the production of PMBs by theaddition of either polymer or rubber crumb in the eld (i.e. atthe point of use) will be covered in a separate guide. Specicrequirements for PMB emulsions are also excluded from this

guide as these materials require different storage andhandling practises.

Acknowledgements

AAPA wishes to acknowledge the contributions of the followingindividuals and groups:

Technical Writer of Original DraftJohn Rebbechi Roadcor Pty Ltd

Document Review Working GroupStuart Dack BP BitumenTrevor Distin Boral AsphaltNigel Preston Shell

Review Groups:AAPA Binder Producers GroupJohn Arvanitidis CaltexRobert Busuttil AAPAWarren Carter Downer AustraliaStuart Dack BP BitumenTrevor Distin Boral AsphaltGerard Gnanseelan SAMI BitumenJohn Lysenko Fulton HoganSam Maccarrone ExxonMobil

Neil Morcombe Bituminous ProductsNigel Preston Shell

Austroads Asphalt Research Working Group (ARWG)

Austroads Bituminous Surfacings Working Group (BSWG)


2/15GUIDE TO THE MANUFACTURE, STORAGE AND HANDLING OF POLYMER MODIFIED BINDERS

Contents

1. INTRODUCTION 1

2. MANUFACTURE 1 2.1 General 1 2.2 Equipment 1 2.3 Manufacturing process 2 2.3.1 Overview 2 2.3.2 Bitumen supply and storage 2 2.3.3 Combining agent 2 2.3.4 Polymer 2 2.3.5 Pre-blending 2 2.3.6 Mixing 2 2.3.7 Storage of nished product 3 2.3.8 Testing and release of product 3 2.3.9 Loading gantry 3

2.4 Product testing and evaluation 3 2.5 Temperature 3 2.6 Non-conforming products 3

3 SAMPLING AND TESTING 4 3.1 Sampling 4 3.2 Laboratory Testing 4 3.3 Tracing Properties of Delivered Materials 5 3.4 Material Safety Data Sheet (MSDS) 6

4 TRANSPORT, STORAGE AND APPLICATION 6OF PMBs

4.1 General handling and safety requirements 6 4.2 Special requirements for PMBs 6 4.2.1 Temperature 6

4.2.2 Moisture 6 4.2.3 Cleaning materials 6 4.2.4 Segregation 6 4.2.5 Loading of delivery vehicles 7 4.2.6 Reheating during transport 7 4.2.7 Delivery into storage tanks or 8

bitumen sprayers4.2.8 Field sampling 8

5 ASPHALT WORK 9

5.1 General 9 5.2 Production of asphalt mixes 9 5.3 Placement and Compaction 9

6 SPRAYED SEALING WORK 9 6.1 General 9 6.2 Field procedures 9 6.2.1 General handling requirements for PMBs 9 6.2.2 Cutter 10 6.2.3 Adhesion Agent 10 6.2.4 Aggregate Precoating 10

REFERENCES 11

GLOSSARY 12

Australian Asphalt Pavement Association Limited (AAPA)AAPA is a non-profit organisation formed to promote the economic use of asphalt based on sound technical grounds. The Associations MissionStatement for Research and Development is to ensure the attainment of the optimum level of quality and long-term performance in flexiblepavement design, construction and maintenance. The AAPA Technology Committee manages the AAPA R&D Program for Asphalt Research

and Technology and works in close cooperation with the Austroads Pavement Reference Group. The research programs are coordinated andcomplementary.

Reproduction of extracts from this publication may be made subject to due acknowledgement of the source.


3/15GUIDE TO THE MANUFACTURE, STORAGE AND HANDLING OF POLYMER MODIFIED BINDERS 1

1. INTRODUCTION

This guide to best practice has been prepared by themanufacturers and users of Polymer Modied Binders (PMBs)to:

Provide guidelines for the manufacture and handling ofhot PMBs.

Provide assurance to end users of the consistent manufacturing quality of delivered products.

Reduce the potential for degradation and contamination due to inappropriate handling or heating during thedelivery, storage and application processes.

PMBs generally consist of a blend of paving grade bitumenand polymer or rubber crumbs. In some cases, combiningagents and other additives are added to the base bitumen to

assist in blending and achievement of particular performancecharacteristics. The normal safety, quality and environmentalconsiderations involved in the manufacture, storage andhandling of a PMB includes:

Accurate blending of materials and control of manufacture to ensure that the product conforms to the requiredspecication.

Monitoring and control of temperature at all phases of manufacture, storage, transport and eld use to avoidpremature deterioration of polymers or rubber crumbs at

high temperatures. Maintenance of the homogeneity of some mixtures that

may segregate. Avoidance of contamination with other products that may

alter performance characteristics of the product.

A number of different organisations may be involved in themanufacture, sampling and testing, transport and applicationof PMBs. Control throughout the process needs to becoordinated and responsibility accepted by the variousorganisations.

This guide is intended to be complementary to the followingpublications:

AAPA HS&E Guide No. 5: Guide to the safe use of SBS

Austroads Bituminous Materials Safety Guide , AP-G41/08

Austroads Specication Framework for Polymer Modied Binders and Multigrade Bitumens , AG:PT/T190

Austroads Guide to the Selection and Use of PolymerModied Binders and Multigrade Bitumens, AP-T42/06

Austroads Modied Binder Test Methods ( http://www.austroads.com.au/pavements )

AAPA Advisory Note 7: Guide to the Heating and Storage of Binders for Sprayed Sealing and Hot Mixed Asphalt

Australian Dangerous Goods Code , 7th Edition (October 2011).

Other relevant publications are referenced at the end of thisdocument, including Austroads guides, Technical Reports andPavement Work Tips.

2. MANUFACTURE

2.1 General

The manufacturer should establish, document and maintain aquality system to ensure that the products supplied conform tothe stated specications. The quality system should consist ofprocedures, regular inspections and tests and/or assessmentsand the use of the results to control the quality of the nishedproduct. A quality system conforming to the requirements of ISO9001 and made specic to the requirements of the AustroadsSpecication Framework for Polymer Modied Binders andMultigrade Bitumens and the AAPA Guide to the safe use of SBS ,is considered to satisfy the above requirements.

The results of inspections, tests or assessments requiringaction should be recorded, as should any action taken. Theaction to be taken when control values or criteria are not metshould be recorded and retained for the period specied in themanufacturers quality procedures.

2.2 Equipment

Testing - all laboratory weighing, measuring and testingequipment should be calibrated and regularly inspected

according to documented procedures, frequencies and criteria.

Manufacturing - all equipment used in the manufacturing processshould be regularly inspected, calibrated and maintained toensure use, wear or failure does not cause inconsistency in themanufacturing process.

Inspections and maintenance should be carried out and recordedin accordance with the manufacturers written procedures, andthe records retained for the period dened in the manufacturersquality procedures.



2.3 Manufacturing process

2.3.1 OverviewA general ow diagram for the process of PMB manufactureusing a high shear mill is shown in Figure 1. Further noteson the requirements for each element of the manufacturingprocess are described in the following sections.

Figure 1: Manufacturing process

2.3.2 Bitumen supply and storage

The consistency and quality of the base bitumen used forPMB manufacture should be monitored, for example, throughthe use of suppliers certicates of compliance, to ensureappropriateness for PMB manufacture. Similarly, bitumen instorage should be monitored to ensure no adverse changesoccur that may adversely impact PMB quality. Systems shouldidentify procedures for assessing the inuence of changesin source of bitumen materials on the required proportionsof other component materials and/or properties of themanufactured PMB.

2.3.3 Combining agent

Combining agents are sometimes added to PMBs to improvetheir performance properties and shelf life and should complywith the requirements of the AAPA Guide to the safe use of

SBS . Acceptance criteria and storage conditions for combiningagents should be documented.

Most PMBs are sufciently stable at normal processing andapplication temperatures. However, the inclusion of combiningagents and other additives, coupled with higher temperaturesthan normally used with conventional bitumen, can produce anoticeable increase in fuming.

It is the responsibility of the manufacturer to exclude the useof ingredients that have known adverse health effects and toensure that all relevant safety precautions are followed, as setout in the suppliers Material Safety Data Sheet (MSDS).

2.3.4 Polymer

The common generic polymer types used for the manufactureof PMBs specied in the Austroads Framework for PolymerModied Binders and Multigrade Bitumens are StyreneButadiene Styrene (SBS), Polybutadiene (PBD) and Ethylene

Vinyl Acetate (EVA). These materials are generally proprietaryproducts manufactured to strict quality standards. Experiencehas shown that a supplier certicate of compliance providesadequate verication of the quality of these materials.

The characteristics of rubber crumbs used in the modication of

bitumen are specied in Table 5.5 of the Austroads SpecicationFramework for Polymer Modied Binders and MultigradeBitumens , AG:PT/T190. Incoming rubber crumb should betested for compliance against these requirements. Every effortshould be made to ensure that the rubber crumbs are free ofmoisture and foreign materials, such as steel and bre. Rubbercrumbs should be stored in a manner that prevents exposure torain and moisture.

2.3.5 Pre-blendingWhere raw materials are required to be pre-blended, procedures

should be established and documented for proportioning,mixing and storing the blended material.

2.3.6 MixingComponent materials should be thoroughly mixed to ensureproduction of a homogeneous PMB. The design of mixingequipment varies considerably depending on the type of PMBbeing manufactured and can vary from high shear mills usedto blend SBS pellets to low shear agitation for blending rubbercrumbs. Critical elements that are common to all processesinclude procedures for proportioning of materials, temperaturecontrol, mixing time and conditions, and maintenance andcleanliness of equipment.

Bitumentank Combining

Agent tankPolymer

Pre-blendtank

Mill

Finishedproduct

tank

Loading Gantry



2.3.7 Storage of nished product

Tanks for the storage of nished product should be designedto minimise deterioration in storage, with strict control oftemperature, minimal surface area to reduce oxidation, andprovision for mixing or circulation to ensure that the productremains homogenous in storage. The heating system shouldbe designed such that the PMB is not exposed to highcontact temperatures around the heating elements or ues forprolonged periods. Prolonged exposure of PMBs to heatingelements may result in deterioration and carbonisation of thebinder. It is essential to provide good circulation of the PMBaround heating elements or ues, either through the use ofmechanical stirrers and/or by circulating the tank contentswith a pump. A tank heating system commonly used for PMBstorage uses heat transfer oil and automated temperaturecontrols to limit overheating.

While PMBs are generally manufactured for immediate delivery,any extended storage should be documented and monitoredto ensure product conforms to the specied characteristics.

2.3.8 Testing and release of product

Requirements for product testing and treatment of non-conforming product are outlined in Sections 2.4, 2.6 and 3.2.

2.3.9 Loading gantryAll supply lines throughout the plant, including loadingequipment, should be designed and procedures establishedso as to avoid contamination during change of product orcleaning of supply lines. The use of oils such as kerosene,diesel, or gas oil for ushing lines should be avoided. Wherelines need to be ushed, it should be done with hot bitumenor nished product. Any oils used for ushing or cleaning ofsupply lines should be collected and disposed of separatelyand should not be added to products or components instorage or delivery vehicles.

2.4 Product testing and evaluation

The manufacturer should establish procedures to ensure thatconformance to the specied characteristics are maintained.The means of control are:

a) By determining the appropriate PMB characteristics using the tests and test frequencies specied in the Austroads Specication Framework for Polymer Modied Binders and Multigrade Bitumens (AG:PT/T190);

b) Routine control of product quality should be on a basis of checks, of a type and frequency to be dened and

documented, to ensure that properties do not change signicantly from those specied.

NOTES:

1. Where testing is required on each batch, a batch isconsidered to be the quantity of binder produced andstored in one tank once the production run into that tankhas been completed. The batch can be considered toremain the same as long as no new production has beenadded.

2. The manufacturer should establish manufacturing targetsfor all test properties. Manufacturing targets may bedifferent to specication limits.

2.5 Temperature

The manufacturer should establish guidelines for the heatingand storage of PMBs to avoid fuming or degradation of bindersin the manufacturing process, supplier storage, transport, userstorage and application. Guidelines should include the rangeof application temperatures, the maximum holding time at themaximum application temperature, the recommended storagetemperature and the maximum time that materials may be heldat the recommended storage temperature.

A summary of manufacturers guidelines for heating and storage

is published in AAPA Advisory Note 7 - Guide to the Heatingand Storage of Binders for Sprayed Sealing and Hot MixedAsphalt. Manufacturers should ensure that agents and users areprovided with current guidelines if these have changed sincepublication pending updating and re-issue of AAPA AdvisoryNote 7.

2.6 Non-conforming productsThe manufacturer should have written procedures that specifyhow non-conforming products are dealt with. Any such non-

conformances should be recorded and the records kept for theperiod dened in the manufacturers written procedures.Such written procedures are normally incorporated in aquality system.



3. SAMPLING AND TESTING

3.1 General

A means should be provided to safely take a representativesample from any point in the supply chain. All materialsshould be sampled in accordance with Austroads test method

AG:PT/T101, Method of sampling polymer modied binders,polymers and crumb rubber , which provides for:

Sampling of raw materials (polymer and rubber crumb) Sampling of PMBs: - From bulk storage - During loading - From rail and road tankers - From sprayers.

It is important to ensure that samples collected are truly

representative of the material being sampled.Therefore it is essential that PMBs arethoroughly circulated and polymers and rubbercrumbs are thoroughly mixed prior to samplingto ensure they are homogeneous and thatsamples are representative.

All bulk storage tanks should be tted witha sampling valve to facilitate sampling inaccordance with AG:PT/T101. Sampling valvesshould be situated in a convenient and safelocation for sampling and a permanent platformattached to support the sample containerduring lling. After lling, the sample containershould be placed in a safe location and allowedto cool.

The sample size should be sufcient to allow all requiredtesting and generally will be at least one litre. Reheating ofsamples should be avoided.

All sampling should be undertaken by properly trainedand qualied personnel. The unit of competency on SafelyHandling Bituminous Materials, which forms part of aCerticate II in Bituminous Surfacing, should be used asa guide to national competency training and assessmentstandards.

Sampling should be accompanied by a visual check foruniformity, texture or unusual odour. Any observation of unusualsample characteristics should be recorded on the samplecontainer.

The following information should be provided with the sample,either on the label (see example Figure 2) or an accompanyingform (see AG:PT/101 for full requirements):

Desig nation or classication of the material being sampled Identi cation mark Name of supplier/manufacturer Date, time and location of sampling Type, batch number and identifying number of container,

vehicle or storage tank from which the sample was taken Quantity of bulk material being sampled

Temperature of material being sampled Name of sampler Any other comments.

Figure 2: Example of sample label

All samples should be handled in accordance with Austroadstest method AG:PT/T102, Protocol for Handling ModiedBinders in Preparation for Laboratory Testing .

3.2 Laboratory TestingLaboratory testing should be undertaken in a NATA accreditedfacility and in accordance with the relevant Austroads testmethods.

The types of tests and minimum frequency of testing should bein accordance with the requirements as set out in the AustroadsSpecication Framework for Polymer Modied Binders andMultigrade Bitumens (AG:PT/T190) or as agreed between thesupplier and the purchaser.

Product name & grade _______________________ OLEXOBIT AB6 (A10E)

Manufacturer ______________________________ BP Australia

Date, time & location of sampling _______________ 22/4/2004 10:35 BP Altona

Sample identification________________________ 1234

Batch / delivery docket number ________________ A04P0443

Tank / vehicle number _______________________ ALB201

Quantity & temperature of material being sampled _ 24,000 L at 186C

Name of sampler ___________________________ Fred Jones

Comments_________________________________ Sample for release testing

PMB SAMPLE



3.3 Tracing Properties of Delivered Materials

Experience and testing has shown that often a non-compliancein specied properties is due to degradation during transport,reheating, cleaning transfer lines and application procedures.From time to time protocols may be established for monitoringthe properties of materials at the point of delivery orapplication. A ow chart of sampling, recording and testing isshown in Figure 3. These procedures may be used:

As a project fo r the development and verication ofhandling protocols. Such projects may be conducted in association with a particular client (e.g. state roadauthority).

To maintain prod uct traceability. In this case eld samplesare not tested, but held in storage for reference testingfor compliance with contract conditions. Samples aregenerally retained for the duration of the contract defectsliability period.

In order to provide adequate traceability, delivery dockets for

PMBs should generally contain the following information:

Date PMB Class Origin Sampling point Manufacturing certi cate number or batch number Customer Customer order number, etc. Delivery details (delivery point, time and temperature) Loading information (date, time, temperature) Quantity/Mass of delivery Product heating information (heating start time, nish time,

total heating time and temperature) Delivery date, time and temperature.

Sampling and labelling of samples should be undertaken inaccordance with Section 3.1.

Figure 3: Sample traceability flow chart

NoFail

Pass

Yes

Yes

No

Binderproduction

Releasetests

performed

Retainedsample for

furthertesting, ifrequired

Bindercarted

direct tosite

Heatingen-route?

Intermediate storageSample taken

Delivery to site

Record time andtemperature

Record time & temperature

Sample taken

Sample taken

Re-process



3.4 Material Safety Data Sheet (MSDS)

Material Safety Data Sheets (MSDS) are used to provide theinformation required to allow the safe handling of substancesused at work. MSDS must comply with the National Code ofPractice for the Preparation of Material Safety Data Sheets,2nd Edition [NOHSC:2011(2003)], published by the NationalOccupational Health and Safety Commission. Suppliers areresponsible for provision of the MSDS which the manufactureror importer has prepared. The MSDS addresses the safety ofboth personnel and the physical environment.

4. TRANSPORT, STORAGE ANDAPPLICATION OF PMBs

4.1 General handling and safety requirements

PMBs are transported and applied hot. Safety and handlingprocedures that are applicable to hot bituminous materialsalso apply to PMBs and are described in detail in the AustroadsBituminous Materials Safety Guide , AP-G41/08.

4.2 Special requirements for PMBs

In addition to the general handling and safety proceduresapplicable to all bituminous materials, attention should be paidto those issues which have the potential to cause a reduction inthe quality and effectiveness of PMBs. These include:

Effect of excessive temperatures, extended periods of storage at elevated temperatures, and/or multiplereheating cycles.

Potential fo r contamination during change of product intransportation vehicles and storage tanks.

Potential f or contamination with materials used forcleaning and ushing supply lines.

Potent ial for some PMB mixtures to segregate in storage.

Method of reheating, e.g. need to recirculate productwhile reheating.

As a further conrmation that PMBs have not suffered unduedeterioration during transport, samples may be required of theproduct at the point of delivery or immediately prior to use inasphalt mixtures or sprayed sealing work (see Section 3.3).

4.2.1 TemperaturePMBs should not be heated to, stored or held at temperaturesor for periods greater than that recommended by the

manufacturer. During handling, every effort should be made

to keep the PMB at the minimum temperature that will alloweffective use so that the risk of thermal degradation andoxidation is minimised. Similarly, the time that the PMB is kept atelevated temperatures prior to application should be minimised.

AAPA Advisory Note 7 should be taken as a guide to themaximum application temperature, holding time at maximumapplication temperature, storage temperature and maximumtime at recommended storage temperature.

PMBs should never be heated to a temperature greater than therecommended maximum application temperature. Generally,only the quantity required for immediate use should be heatedto the application temperature and reheating avoided, wherepracticable.

4.2.2 MoistureThe presence of even small quantities of water can causefoaming and boil-over of hot PMB. Care should be takento ensure that road tankers, storage tanks or bitumen sprayersare free from water arising from the presence of condensationor residual bitumen emulsion. A visual check for condensationshould always be made where tanks have been out of service forsome time.

4.2.3 Cleaning materialsIt is preferable to use diesel or high-ash kerosene to ush lines.

The amount of cleaning material should be kept to a minimumand drained from tanks and delivery lines for separate disposalin accordance with local requirements. Cleaning materialsshould not be ushed into binder storage tanks or deliveryvehicles.

Kerosene or other types of approved cutter oil used for cleaningdelivery lines may be drawn into bitumen sprayers where thePMB is being prepared for spraying. An allowance for thequantity of cutter oil used for cleaning should be made indetermining the total quantity of cutter oil to be added.

4.2.4 SegregationSome PMB types, particularly those modied by rubber crumbor high levels of SBS polymer, are susceptible to segregationduring long distance transport and long term storage.Manufacturers should advise users of susceptible materials andprovide guidelines for minimising segregation and/or remixing.Users should adhere to manufacturers guidelines whereapplicable. The use of stirrers in storage tanks and belly augersin sprayers will help ensure homogeneity can be maintained for

PMBs that are susceptible to segregation.



4.2.5 Loading of delivery vehicles

Vehicles used to transport PMBs should be emptied of theprevious product to the minimum practical level to minimisecontamination.

Comprehensive guidance on the procedures to follow whenchanging grades carried within a road tanker is provided inAP-G41/08. A summary of product changeover proceduresrelevant to PMBs is provided in Table 1. Particular attentionneeds to be paid when loading hot PMB into a tanker that haspreviously contained a bitumen emulsion due to the potentialfor hazardous foaming and boil-over of the tank contents.

Vehicles previously used for delivery of bitumen emulsionproducts should not be used for the delivery of PMB unlessthoroughly cleaned.

The risk of subsequent product contamination is particularlyhigh when vehicles have been used to transport PMBsincorporating rubber crumb. It is recommended that suchbinders be transported only in dedicated tankers.

Care should be taken to ensure that tankers that have notbeen in use for some time are free from condensation.

Notes to Table 1:

OK: OK to load. In all cases the previous productshould be fully drained.

Drain & Flush: Drain vehicle of product and ush withkerosene wash and fully drain and dry out, orboil out with uncontaminated standard gradebitumen as per your companys workinstruction.

4 standard Should take minimum 4 loads of C170, C320bitumen loads: or C600 prior to loading.

4.2.6 Reheating during transport

Delivery vehicles can generally transport materials for periods ofup to 4 to 6 hours with only a minor loss in temperature, usuallyno more than about 15C. Where there is only a small loss intemperature, PMBs may be transferred directly into storagetanks without reheating or, where the PMB is required to beat an application temperature, for example delivery direct tosprayed sealing operations, they may be reheated in the deliveryvehicle prior to transfer into the bitumen sprayer.

Where longer transport times and greater loss of temperatureare involved, materials should be periodically reheated to ensurethat temperature is maintained within the recommended limits.For convenience, this may be done in conjunction with regularrest stops.

The following points should be noted when reheating PMBs:

1. At no time should the recommended maximum temperaturefor the material be exceeded as indicated in Advisory Note 7.

2. Bitumen road tankers or sprayers tted with open ameburners should never be heated while in motion.

3. Drivers should be in attendance and monitor the process at all times while burners are in operation.

4. To avoid PMB degradation, the preferred rate of heating should be approximately 10C per hour and not more than 15C per hour.

5. Tankers should be circulated during heating and for at least 20 minutes after heating and before discharge.

6. Generally, temperature checks should be undertaken every four hours and reheating applied when the temperature drop is greater than 15C.

7. For PMBs incorporating 15% or higher rubber crumb content, circulation should be continuous during transport and heating with the temperature being maintained within the range recommended by the manufacturer and checked at intervals not exceeding 3 hours.

Table 1: Product changeover guidelines

Previous Load PMB

Bitumen OKCutback bitumen primers &

precoatsDrain

Bitumen emulsion Drain & flush

Fuel oil Drain & flush

Suspected presence ofmoisture

Drain & flush

PMB OK

Crumb rubber bitumen 4 Standard bitumen loads*

Other XRefer to supplier for advice



4.2.7 Delivery into storage tanks or bitumen sprayers

(a) Asphalt plants and other xed storage

Where a PMB is placed in a storage tank previously usedfor hot bitumen, multigrade bitumen or a different grade ofPMB, the tank should be emptied to the minimum practicablelevel in order to minimise any diluting effect on the polymer

content of the delivered PMB. Where the residual contentsof a storage tank comprise a different grade of PMB or othermodied binder, the manufacturers advice should be soughton any potential incompatibility with the fresh product. Table2 provides a guide to the relative risk from contamination byprevious tank contents

(b) Road tankers, mobile storage tanks, and bitumen sprayersused for sprayed sealing work

Road tankers, mobile storage tanks or bitumen sprayerspreviously used for uxed or cutback bitumen should be totallyemptied before lling with PMB (see also Section 4.2.5).

Notes to Table 21. Risk prole:

Low Residual tank contents have a low risk of performance impact on the product being added, for example topping up of modied binder with hot bitumen may enhance rather than detract from normal use of bitumen.

Medium While resid ual tank contents may not have a majorimpact on performance of added product, tank levels should

generally be reduced to minimum levels before adding new materials.

High Reduction of tank contents to minimum level is essential. Low levels of contamination may be tolerated but generally not more than 10% of diluting product.

Very high Contamination could have a serious impact on performance. Preferably, the tank should be completely emptied prior to adding new materials. Where complete emptying is not practicable, risk should be reduced by ushing the tank with

4.2.8 Field sampling

Representative samples may be required to be taken of a PMBprior to its use. Such samples should be taken during ofoadingof road tankers and during transfer into bitumen sprayers priorto the addition of cutters and adhesion agents. In the caseof asphalt manufacture, a sample can be taken from the PMBstorage tank or from the ring main during circulation or use.

Field samples should be taken at locations and frequencies asagreed between supplier and purchaser. All sampling shouldbe performed in accordance with the procedures described inAG:PT/T101.

Field samples should be clearly identied to provide traceabilityfrom supplier to the point of sampling. Unless otherwisespecied or directed, eld samples are not required to be testedimmediately and should be stored in sealed containers in a

secure location for a minimum period of six months, or for theduration of the contract defects liability period, whichever is thegreater. Samples not required for further testing beyond thatperiod may then be discarded.

a more compatible material or using the tank, for example, witha load or part load of hot bitumen or PMB in an application wherethe performance properties of the PMB are not critical.

2. Storage of bitumen emulsion in tanks previously used for hotbitumen products usually requires the tank to be completelyemptied and cleaned before adding bitumen emulsion.

3. Hot bituminous materials should not be added to tanks previously used for bitumen emulsion unless all traces of moisture have been

removed.

4. Care should be taken when adding materials to tanks that havebeen used for storage of crumb rubber modied binder. Usually

a series of loads of hot bitumen or hot cutback bitumen arerequired before use for any other critical application.

5. Multigrade to be treated the same as bitumen for product changeover purposes

6. Refer to AP-G41/08 Austroads Bituminous Materials Safety Guide for specic requirements

Table 2: Relative risk from contamination by previous tank contents

Product being deliveredPrevious tankcontents

Cutbackbitumen

Bitumenemulsion

Bitumen Low modificationPMB

Highmodification

PMB

Crumb rubberbitumen

Cutback bitumen Not applicable See note 2 Medium Very high Very high High

Bitumen emulsion See note 3 Note 6 See note 3 See note 3 See note 3 See note 3

Bitumen Medium See note 2 Not applicable Medium High Medium

Low modification PMB Medium See note 2 Low Not applicable Medium Medium

High modification PMB Medium See note 2 Low Medium Not applicable Medium

Crumb rubber bitumen See Note 4 See note 2 See Note 4 See Note 4 See Note 4 Not applicable


11/15



If using a particular class of PMB for the rst time, it is advisable to check with the manufacturer about any special

handling or application requirements. For a SAM or SAMI application, the pavement and air temperatures need to be above 20C and rising. Higher temperatures are required if wind chill is expected to cool the binder quickly after spraying. Wind chill will cause the

binder to skin more quickly and this will delay, or prevent, wetting and development of adhesion. The exception to this is S35E produced with PBD, which may be used at the lower pavement and air temperatures normally accepted for Class 170 work (approximately 15C), but only where recommended by the manufacturer. The presence of moisture in any form should be avoided. Avoid spraying PMBs in changeable weather conditions. Spraying should only be applied to a dry pavement surface and aggregates should be precoated and dry (at most damp). This may require the aggregate stockpile to be covered with waterproof material. Warm and dry weather conditions before and after application of the PMB seal are essential. Wet weather up to a week after application may result in the aggregate stripping. Spraying should not be undertaken if wet weather is predicted within several days after application. Adhesion agent should be added to the PMB in the sprayer no more than half an hour prior to spraying and the load thoroughly circulated. Exceptions may apply to a few specic heat stable adhesion agents known to

retain effectiveness after several hours at high temperatures. Such materials should only be used in accordance with the suppliers recommended maximum temperature and storage times. The PMB/aggregate/precoating material/adhesion agent system should be evaluated, well in advance of the work, using both the initial adhesion and plate stripping tests. Check with the manufacturer if unsure of the details. Cutter oils are generally required to facilitate spraying of PMBs and wetting of aggregate. Some of the more viscous PMBs will require the use

of larger spray nozzles; e.g. B6 or B8 nozzles, depending on binder viscosity, to ensure a uniform transverse binder application.

6.2.2 CutterA summary of the requirements for cutting back of PMBs isprovided in Austroads/AAPA Work Tip No. 27 Sprayed Sealing Cutting Back of Polymer Modied Binders.

Additional advice on cutting back of PMBs and other sprayedsealing construction practices are provided in the AustroadsGuide to the Selection and Use of Polymer Modied Binders andMultigrade Bitumens or may be obtained from manufacturers orsuppliers.

Take extreme care when blending cutter oil with PMB. AP-G41/08

should be consulted for further information.

6.2.3 Adhesion AgentIn general, hot PMBs are more viscous and cohesive thanconventional bitumen and consequently less able initially towet and adhere to aggregate particles. If there are problemsdeveloping adequate adhesion between the PMB and theaggregate, then it is recommended to promote bonding byadding extra adhesion agent. A general rule of thumb in thiscase is to double the concentration of adhesion agent comparedto conventional bitumen, i.e. add about 1% of adhesionagent instead of 0.5%. The adhesion agent selected shouldbe compatible with the type of polymer in the binder and theaggregate precoating material.

6.2.4 Aggregate PrecoatingIt is important to only use aggregate that is of good quality andthat is dry and free from dust. It is also important to adhere torecommended cutting practice. This applies to all PMB seals,including those applied on lower trafc volume roads. However,initial adhesion of PMB to the aggregate particles may still be

difcult to achieve, especially with increasing concentrations ofpolymer and rubber crumb. It is therefore essential to precoatthe aggregate, preferably with a bitumen-based precoat thatcontains about 1% of adhesion agent. This should ensure botheffective initial adhesion and longer term retention of theaggregate.



REFERENCE

AAPA (1998) Advisory Note 14 Summary of SBS Bitumen FumeMonitoring Project.

AAPA (1998) HS&EGuide No 5 Guide to the safe use of SBS.

AAPA (2004) Advisory Note 7 Guide to the Heating and Storageof Binders for Sprayed Sealing and Asphalt Manufacture.

AUSTROADS (2000) AP-T42/06 Guide to the Selection and Useof Polymer Modied Binders and Multigrade Bitumens.

AUSTROADS (2006) AG:PT/T101 Method of Sampling PolymerModied Binders, Polymers and Crumb Rubber.

AUSTROADS (2008) AG:PT/T102 Protocol for Handling

Modied Binders in Preparation for Laboratory Testing.

AUSTROADS (2008) AP-G41/08 Austroads Bituminous MaterialsSafety Guide.

AUSTROADS (2010) AGPT/T190 Specication Framework forPolymer Modied Binders and Multigrade Bitumens.

AUSTROADS/AAPA (1998) Pavement Work Tip No. 13Temperature Characteristics of Binders in Asphalt.

AUSTROADS/AAPA (2001) Pavement Work Tip No. 27 SprayedSealing Cutting Back of Polymer Modied Binders.

NOHSC:2011(2003) National Code of Practice for thePreparation of Material Safety Data Sheets 2nd Edition.

Austroads test methods and selected Austroads TechnicalReports may be accessed and downloaded, free of charge,from the Austroads web-site at www.austroads.com.au.

AAPA Advisory Notes, HS&E Guides, and Austroads/AAPAWork Tips may be accessed and downloaded, free of charge,from the AAPA web-site at www.aapa.asn.au.



GLOSSARY

Adhesion agent A substance used for the purpose ofimproving the adhesion between a bituminous binder andthe aggregate. The term generally refers to adhesion in thepresence of water.

asphalt (used rather than the US term asphaltic concrete) A mixture of bituminous binder and aggregate with orwithout mineral ller, produced hot in a mixing plant, which isdelivered, spread and compacted while hot.

bitumen A very viscous liquid or a solid, consisting essentiallyof hydrocarbons and their derivatives, which are soluble incarbon disulphide. It is substantially non-volatile and softensgradually when heated. It possesses waterproong and

adhesive properties. It is obtained from native asphalt or byprocessing the residue from the rening of naturally occurringcrude petroleum.

bitumen emulsion A liquid product in which a substantialamount of bitumen (with which some oil may be mixed) issuspended in a nely divided condition in water by means ofemulsifying and stabilising agents.

crumb rubber Rubber particles manufactured from waste orreclaimed rubber products such as vehicle tyres and graded to

conform to a specied size range. Used in bitumen to improvebinder properties.

cutback bitumen Bitumen to which cutter oil (kerosene) hasbeen added to achieve a temporary reduction in viscosity.

cutter (kerosene) A light petroleum distillate added tobitumen to temporarily reduce its viscosity (cutback bitumen).A high-ash cutter is a cutter with a ash point above 60C.

material safety data sheet (MSDS) A document thatprovides health and safety information about products,substances or chemicals that are classied as hazardoussubstances or dangerous goods.

multigrade bitumen A bituminous binder which, at highservice temperatures shows good resistance to ow, and at lowtemperatures does not exhibit the high stiffness (leading tobrittleness) normally experienced with conventional bitumenbinders.

polymer A predominantly organic substance comprising a verylarge number of chemical entities. These chemical entities maycomprise identical segments (producing a homopolymer) or acombination of two or more different segments (producing acopolymer).

polymer modied binder (PMB) A binder consisting ofpolymeric materials dispersed in bitumen with enhanced binderperformance for particular applications.

sprayed seal (chip seal) A thin layer of binder sprayed ontoa pavement surface with a layer of aggregate incorporated andwhich is impervious to water.

strain alleviating membrane (SAM) A sprayed seal with thebinder containing a relatively large concentration of rubber orpolymer modier. It is used to absorb strains that occur in a roadpavement and thereby reduce reection cracking.

strain alleviating membrane interlayer (SAMI) Similar to aSAM, but provided as an interlayer before placing an asphaltoverlay.


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The Australian Asphalt Pavement Association is a non-protorganisation formed to promote the economic use of asphalt and

bitumen bound products based on sound technical and commercialgrounds.

Throughout its history, AAPA has maintained as its major objectivethedissemination of technical knowledge aimed at continualimprovement in Asphalt technology.

AAPA Members include manufacturers of asphalt and other bitumenbound products, State Road Authorities, Local Government,pavement engineering consultants, material suppliers, plant andmachinery manufactures paving and sealing contractors andindividuals interested in asphalt technology.

Level 2, 5 Wellington StreetKew Victoria 3101 AUSTRALIA

Telephone: (03) 9853 3595Fax: (03) 9853 3484Email: [email protected]: www.aapa.asn.au

Documents

AAPA Guide to the Handling Storage Manufacture of PMB's Final Version Jan 2013.pdf