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Cover of Update of the Austroads Sprayed Seal Design Method
Update of the Austroads Sprayed Seal Design Method
  • Publication no: AP-T68-06
  • ISBN: 1 921139 65 X
  • Published: 9 September 2006

This report is an update of earlier Austroads sprayed seal design procedures based on the philosophy of filling 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. Adjustments and allowances are incorporated in the procedures to cater for aggregate shape, traffic level, embedment, existing surface texture, hardness of existing surfaces and absorption of binder by either aggregates or existing substrate.

Updates to AP-T68-06

AP-T236-13 Update of Double / Double Design for Austroads Sprayed Seal Design Methods, published May 2013, supersedes Sections 6, 7 and 8 of AP-T68-06.

AP-T310-16 Selection and Design of Initial Treatments for Sprayed Seal Surfacings, published July 2016, supersedes Section 12 of AP-T68-06.

  • Summary
  • 1. Introduction
    • 1.1. General
    • 1.2. Selection of treatment type and materials
    • 1.3. Application of seal design procedure to various seal types
      • 1.3.1. Single/single seals
      • 1.3.2. Double/double seals
      • 1.3.3. Geotextile reinforced seals and fibre reinforced seals
    • 1.4. Design philosophy
      • 1.4.1. Single/single seals – size 10 mm aggregates and larger
      • 1.4.2. Single/single seals – size 7 mm and smaller aggregates
      • 1.4.3. Other seal types
    • 1.5. Calculation of design traffic
      • 1.5.1. General
      • 1.5.2. Single carriageway – two way traffic
      • 1.5.3. Dual carriageway – one way traffic
      • 1.5.4. Large heavy vehicles (LHV)
      • 1.5.5. Short term traffic variations
      • 1.5.6. Access roads to quarries, mining locations, etc.
    • 1.6. Average least dimension (ALD)
  • 2. Single/Single Seals - Size 10mm and Larger Aggregates
    • 2.1. Design binder application rate
      • 2.1.1. Abbreviations
      • 2.1.2. General
      • 2.1.3. Basic Voids Factor (Vf)
      • 2.1.4. Adjustments to the Basic Voids Factor
      • 2.1.5. Design Voids Factor (VF)
      • 2.1.6. Basic Binder Application Rate (Bb)
      • 2.1.7. Allowances applied to basic binder application rate
      • 2.1.8. Design Binder Application Rate (Bd)
    • 2.2. Aggregate Spread Rate
  • 3. Single/Single Seals - Size 7mm and Smaller Aggregates
    • 3.1. General
    • 3.2. Binder application rate
      • 3.2.1. Basic binder application rate (Bb)
      • 3.2.2. Design Binder Application Rate (Bd)
    • 3.3. Aggregate Spread Rate
  • 4. Single/Single Seal with Polymer Modified Binder
    • 4.1. General
    • 4.2. Design for size 10 mm and larger aggregate
      • 4.2.1. PMB binder application rate
      • 4.2.2. SAMI treatments
      • 4.2.3. Aggregate Spread Rate
    • 4.3. Size 7 mm and smaller aggregates
      • 4.3.1. Binder application rate
      • 4.3.2. Aggregate Spread Rate
  • 5. Single/Single Seals with Bitumen Emulsion Binder
    • 5.1. General
    • 5.2. Single/single seals – aggregates size 10 mm and larger
      • 5.2.1. Binder application rate
      • 5.2.2. Aggregate Spread Rate
    • 5.3. Single/single seals – aggregates size 7 mm and smaller
      • 5.3.1. Binder application rates
      • 5.3.2. Aggregate Spread Rate
  • 6. Double/Double Seals
    • 6.1. General
    • 6.2. Both applications with little or no trafficking between applications
      • 6.2.1. General
      • 6.2.2. First application
      • 6.2.3. Second application
      • 6.2.4. Varying surface texture of finished seal
    • 6.3. Second application delayed
      • 6.3.1. General
      • 6.3.2. Aggregate Spread Rate
  • 7. Double/Double Seal with PMB
    • 7.1. General
    • 7.2. Both applications with little or no trafficking between applications
      • 7.2.1. First application using a PMB
      • 7.2.2. Second application using a PMB
      • 7.2.3. Second application using C170/320, multigrade
    • 7.3. Second application delayed
  • 8. Double/Double Seals with Bitumen Emulsion Binder
  • 9. Geotextile Reinforced Seals (GRS)
    • 9.1. General
      • 9.1.1. Applications
      • 9.1.2. Geotextile fabric
      • 9.1.3. Design procedure
    • 9.2. Binder application rate
      • 9.2.1. Preliminary Design Binder Application Rate
      • 9.2.2. Binder fabric retention allowance
      • 9.2.3. Final Design Binder Application Rate
    • 9.3. Aggregate Spread Rate
  • 10. Fibre Reinforced Seals
    • 10.1. General
    • 10.2. Binder application rate
    • 10.3. Design Aggregate Spread Rate
  • 11. Selection of Treatment Types
    • 11.1. General
    • 11.2. Specialty seals/treatments
      • 11.2.1. Inverted seal
      • 11.2.2. Dry matting
      • 11.2.3. Cape seals
      • 11.2.4. Variable spray rates
      • 11.2.5. Surface enrichment
      • 11.2.6. Rejuvenation
    • 11.3. Binders
      • 11.3.1. Conventional bitumen
      • 11.3.2. Multigrade bitumen
      • 11.3.3. Polymer modified binder (PMB)
      • 11.3.4. Bitumen emulsion
    • 11.4. Geotextiles
    • 11.5. Aggregates
      • 11.5.1. General
      • 11.5.2. Aggregate properties
      • 11.5.3. Selection of aggregate size
  • 12. Priming and Primersealing
    • 12.1. Introduction
    • 12.2. Prime
      • 12.2.1. Function of a prime
      • 12.2.2. Selection and design for priming
      • 12.2.3. When to prime
      • 12.2.4. Life expectancy of prime
    • 12.3. Primerseals
      • 12.3.1. General
      • 12.3.2. Selection of primerbinder
      • 12.3.3. Primerbinder application rates
      • 12.3.4. Selection of aggregate size for primerseals
      • 12.3.5. Aggregate spread rates for primerseals
  • References
  • Appendix A Worked Examples
  • Appendix B Vehicle Classification Table
  • Appendix C Summary of Tables and Design Factors
Related publications
Selection and Design of Initial Treatments for Sprayed Seal Surfacings
AP-T310-16
Update of Double / Double Design for Austroads Sprayed Seal Design Methods
AP-T236-13
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