Guide to Pavement Technology Part 4K - Austroads

1 Guide to Pavement Technology Part 4K: Selection and Design of Sprayed Seals Sydney 2019 Guide to Pavement Technology Part 4K: Selection and Design of Sprayed Seals Prepared by: Steve Patrick Publisher Austroads Ltd. Level 9, 287 Elizabeth Street Sydney NSW 2000 Australia Phone: +61 2 8265 3300 Project manager: John Esnouf Abstract Guide to Pavement Technology Part 4K: Selection and Design of Sprayed Seals is a Guide to the procedures for the selection and design of sprayed seals. This is an update of previous Austroads procedures based on the philosophy of filling up voids in the aggregate matrix with binder, to a depth of about one half to two thirds the height of the aggregate when laying on its least dimension. The Guide discusses the historical background and operational environment of sprayed seals, alongside design, selection and construction procedures for various types of sprayed seals.

2 About Austroads Austroads is the peak organisation of Australasian road transport and traffic agencies. Austroads purpose is to support our member organisations to deliver an improved Australasian road transport network. To succeed in this task, we undertake leading-edge road and transport research which underpins our input to policy development and published guidance on the design, construction and management of the road network and its associated infrastructure. Austroads provides a collective approach that delivers value for money, encourages shared knowledge and drives consistency for road users. Austroads is governed by a Board consisting of senior executive representatives from each of its eleven member organisations: Transport for NSW Roads Corporation Victoria Queensland Department of Transport and MainRoads Main Roads Western Australia Department of Planning, Transport andInfrastructure South Australia Department of State Growth Tasmania Department of Infrastructure, Planning andLogistics Northern Territory Transport Canberra and City ServicesDirectorate, Australian Capital Territory The Department of Infrastructure, Transport,Cities and Regional Development Australian Local Government Association New Zealand Transport Sprayed seal, design, design traffic, aggregate, bituminous binder, average least dimension, embedment, surface texture, geotextiles, bitumen, polymer modified binders, bitumen emulsions, single/single seal, double/double seal, chip seal.

3 Edition published November 2019 Corrections made to Table , Table C3, Section and Section Edition published October 2018 Corrections to light vehicle values in Table C 2: Vehicle volume by lane. Edition published September 2018 Corrections to cross references in Sections and , and binder absorption allowances in Appendix F First edition published August 2018 This Guide was previously published as Guide to Pavement Technology Part 4K: Seals. This new editi on of the Guide has been restructured and content updated to improve overall readability and usability, and incorporates sprayed seal desi gn (Sections 5 and 6), which was previously published in a separate document. The terminology used to describe sprayed seal treatment types has been updated, with some name substitutions and additions, and inclusion of different material usage based on the findings of r ecent Austroads studies (Section 3).

4 New information for selecting sprayed seals is included (Section 4). Various updates to design parameters have been updated to reflect current practice (Section 6). ISBN 978-1-925854-70-1 Austroads Project No. TT1850 Austroads Publication No. AGPT04K-18 Pages 120 Austroads Ltd 2019 | This work is copyright. Apart from any use as permitted under the Copyright Act 1968, no part may be reproduced by any process without the prior written permission of Austroads . This Guide is produced by Austroads as a general Guide only. Austroads has taken care to ensure that this publication is correct at the time of publication. Austroads does not make any representations or warrant that the Guide is free from error, is current, or, where used, will ensure compliance with any legislative, regulatory or general law requirements.

5 Austroads expressly disclaims all and any guarantees, undertakings and warranties, expressed or implied, and is not liable, including for negligence, for any loss (incidental or consequential), injury, damage or any other consequences arising directly or indirectly from the use of this Guide . Where third party information is contained in this Guide , it is included with the consent of the third party and in good faith. It does not necessarily reflect the considered views of Austroads Readers should rely on their own skill, care and judgement to apply the information contained in this Guide and seek professional advice regarding their particular issues. Acknowledgements This Guide was prepared with the assistance of an action group from the Austroads Bituminous Surfacings Working Group, comprising of Robert Busuttil (VicRoads), Steve Halligan (MRWA) and Shawn Mumford (Downer Group).

6 The previous version of this Guide was prepared by Walter Holtrop, John Rebbechi and Allan Alderson. Guide to Pavement Technology Part 4K: Selection and Design of Sprayed Seals Austroads 2018 | page i Contents 1. Introduction .. 1 Background .. 1 The Nature of Sprayed Seals .. 1 Historical Context .. 4 Development of Guides to Sprayed Sealing Practice .. 5 Use of this Guide .. 7 2. Operating Environment .. 8 General .. 8 The Managerial Environment .. 8 Pavement Management Systems (PMS) .. 8 Maintenance Management Systems (MMS) .. 9 Whole-of-life Costing .. 9 User and Community Needs .. 9 Workplace Health and Safety .. 9 Contract Delivery and Contract Specifications .. 10 The Physical Environment .. 10 Traffic .. 10 Existing Pavement Condition.

7 11 Climate and Weather .. 12 3. Types of Sprayed Seal 14 Categories of Sealing Treatments .. 14 Initial Treatments .. 15 Prime .. 15 Initial Seal .. 16 Sprayed Seal (Secondary and Retreatments) .. 17 Single/single Seal .. 17 Multiple-layer Applications .. 18 Aggregate Retention Seal .. 20 High Stress Seals (HSS1 and HSS2) .. 20 Extreme Stress Seal (XSS) .. 20 Strain Alleviating Membrane (SAM) .. 20 Strain Alleviating Membrane Interlayer (SAMI) .. 21 Fibre Reinforced Seal (FRS) .. 21 Geotextile Reinforced Seal (GRS) .. 22 Cape Seal .. 23 Other Treatments .. 23 Variable Rate Spraying .. 23 Salt-affected Pavements .. 23 Surface Enrichment and Rejuvenation 24 High-friction Surface 25 Acrylic Oil Resistant Seal .. 26 Coloured Surface Treatment.

8 26 Dust Laying .. 27 4. Selection of Treatments .. 28 Overview .. 28 Purpose of Sprayed Seals .. 28 Distress Modes .. 28 Selection Process .. 29 Stakeholder Needs .. 29 Performance Requirements .. 30 Whole-of-life Costs .. 32 Guide to Pavement Technology Part 4K: Selection and Design of Sprayed Seals Austroads 2018 | page ii Selection of Aggregate .. 33 Aggregate Properties .. 33 Aggregate Size .. 34 Binders .. 36 Conventional Bitumen .. 36 Multigrade Bitumen .. 37 Polymer Modified Binder (PMB) .. 37 Bitumen Emulsion .. 38 Effect of Spraying Conditions and Delivery System on Binder Selection .. 38 Selecting a Prime .. 39 Selecting an Initial Seal .. 39 Binder Type .. 40 Aggregate Size .. 41 Selecting Speciality Treatments.

9 41 Variable Binder Spray Rates .. 41 Geotextiles .. 42 Selecting a Sprayed Seal .. 42 5. Design Method .. 44 Principles .. 44 Design Traffic .. 44 Traffic Data .. 45 Accuracy of Data .. 46 Distribution of Traffic .. 46 Procedure for Determining Design Traffic .. 46 Equivalent Heavy Vehicle (EHV(%)) .. 48 Short-term Traffic Variations .. 48 Access Roads to Sites such as Quarries and Mining Locations .. 49 Aggregate Size and Shape .. 50 Average Least Dimension (ALD) .. 50 Flakiness Index .. 51 Surface Texture .. 51 Design Process .. 51 Single/single Sprayed Seal .. 51 Double/double Sprayed Seal .. 53 Initial Treatments .. 57 Other Seals .. 58 6. Seal Design Input Parameters .. 60 Voids Factor .. 60 Basic Voids Factor .. 60 Adjustments to the Basic Voids Factor.

10 62 Design Voids Factor .. 64 Binder Application Rate .. 64 Basic Binder Application Rate (Bb) .. 64 Allowances Applied to the Basic Binder Application Rate .. 64 Embedment Allowance (Ae) .. 68 Binder Absorption Allowance (Aba) .. 70 Binder Factor .. 71 Single/single Seals .. 71 Double/double Seals .. 72 Design Binder Application Rate (Bd) .. 72 Geotextile Reinforced Seals (GRS) .. 72 Binder Fabric Retention Allowance .. 72 Bond Coat .. 73 Fibre Reinforced Seals (FRS) .. 73 Guide to Pavement Technology Part 4K: Selection and Design of Sprayed Seals Austroads 2018 | page iii Aggregate Spread Rate .. 73 Influence of ALD .. 73 Influence of Traffic .. 74 Single/single Seals .. 74 Double/Double Seals .. 75 7. Construction .. 77 Pavement /Surface Preparation.