Priming - aapaq.org · Flakiness index Traﬃc Vt Table 2.2 Heavy vehicles Climbing lanes Channelised lanes Table 2.1: Adjustment to Basic Voids Factor for Aggregate Shape (Va) Aggregate

1

AAPA training

Sprayed Seal Design

Australian Asphalt Pavement Associa�on

Design of Rates of Application

  Primes   Primerseals   Seals

– C170 binder – Polymer modified binder – Geotex�le reinforced seals (GRS)

  Surface enrichment


Priming

  Design of Rates of Applica�on based on experience with type of pavement and primer.

  No formal design method


Priming

  Rate of Set-‐Up for cutback primes: – Hot weather – 6 to 12 hrs –  Cool Weather – 12 to 24 hrs –  Cold or cool and damp – 24 to 48 hrs

  Time before applying next treatment –  Cutback prime -‐ 3 days (minimum) –  Emulsion prime -‐ 12 to 24 hrs


Primer

Pavement Grade Rate (L/m²)

Tightly bondedMedium porosity

PorousLimestoneSandstone

Hill gravel, sandStabilisedConcrete

LightMedium

Heavy to v. heavyHeavy to v. heavyMedium to heavy

LightVery light to light

Very light

0.6 – 1.10.8 – 1.10.9 – 1.3

0.7 – 0.9/0.5 – 0.70.7 – 0.9/0.5 – 0.7

0.8 – 1.10.5 – 0.80.2 – 0.4

Guide to Rates of Application of Primer

2

Priming – small scale trial   Small scale trial

  Apply measured quantity by hand   Distribute evenly

  Observe performance

  Design rate

§  Apply measured quan�ty by hand (say 1L) §  Distribute evenly with brush

§  Observe performance

§  Decide on grade and rate


Primersealing

Primerbinder -‐ Rates of Applica�on   No formal design procedure   AUSTROADS design based on:

– Traffic ranges(v/l/d) – Nominal aggregate size – Type of primerbinder – Pavement condi�on – Local experience


Primersealing

Primerbinder – Rates of Applica�on   Determine base rates from AP-‐T68   Add allowances for:

–  Pavement texture –  Possible absorp�on –  Possible aggregate embedment based on using ball embedment test

  Total allowances: –  generally averages + 0.2 to + 0.3 L/m²

Primersealing Primerbinder application rate L/m² @ 15 °C

DesignTraffic (v/l/d)

Aggregate size (mm)

Cutback bitumen

Bitumen emulsion

60%

-150 7 or 5 10

1.3 1.4

1.6 1.8

150 - 1200 7 or 5 10

1.2 1.3

1.5 1.6

1200+ 7 or 5 10

1.1 1.2

1.4 1.5

Aggregate spread rates

Size of aggregate mm

Aggregate spread rate m²/m³

Sand, size 5, size 7

Size 10

130 – 150

110 – 120

Primersealing Typical Aggregate Spread Rates


Update of the Austroads

Sprayed Seal Design Method

AP-‐T68/06

3


Design Philosophy

Basis for method:

  Use of one-‐sized aggregate   Binder should be 50 to 60% up the height of the aggregate   Aggregate par�cles may embed into base   Binder may be absorbed into base   Reseals interlock into the substrate

Design Philosophy

14

Texture for skid resistance

Maximum binder level (65%)

Void loss due to meshing with exis�ng surface ex. concrete (different to embedment in “green” base)

Minimum binder level to provide adhesion of aggregate to base (30%)

ALD 100%

Reorienta�on onto ALD (most stable posi�on)


AP-T68/06 Design

  Sprayed seals are a system – Binder and aggregate spread rate are both important

  Binder design rate of applica�on for – S/S – Unmodified, modified, emulsion binders – Geotex�le and Fibre Reinforced Seal

Aggregate shape adjustment: Va

Traffic adjustment: Vt

Embedment

allowance Ae

Existing surface condition allowance

As Absorption allowance

Basic voids factor: Vf

Design voids factor: VF (Vf+Va

+Vt)

Design Traffic volume

ALD Basic binder

application rate:

Bb

Design binder application rate;

Bd

DESIGN FLOW CHART Binder applica�on rate

Treatment known

AADT known



Embedment allowance


Absorption allowance

Basic voids

factor: Vf

Design voids

factor: VF (Vf+Va+Vt)

Design Traffic volume (v/l/d)

ALD Basic binder application

rate: Bb


Bd

Step 1 -‐ Collect input data

Aggregate   Grading (one sized)   Flakiness Index (FI)   ALD (A)

Design Traffic   Vehicles/lane/day calculated

from AADT   Commercial vehicles

Road geometry   Climbing/channelised lanes

Surface effects   Texture (sand patch)   Aggregate embedment (new

work)   Pavement absorp�on (not

applicable if correctly primed)

Design Input Data - Traffic

  Annual Average Daily Traffic – Representa�ve – Current

  AADT is over all lanes

  Design traffic – Vehicles in each lane

4



Embedment allowance



Basic voids

factor: Vf Design Traffic volume (v/l/d)

ALD Basic binder

application rate: Bb


Bd

Design voids


Step 2 – Determine basic voids factor Vf

Charts using design traffic   Two charts for different traffic

ranges

  Use target line





Embedment allowance



Basic voids


ALD Basic binder

application rate: Bb


Bd

Design voids


Step 3 – Determine adjustments Va & Vt

Aggregate shape Va   Table 2.1   Flakiness index

Traffic Vt   Table 2.2   Heavy vehicles   Climbing lanes   Channelised lanes

Table 2.1: Adjustment to Basic Voids Factor for Aggregate Shape (Va)

Aggregate type Aggregate shape Flakiness index (%)

Shape adjustment Va

(L/m2/mm)

Crushed or partly crushed

Very Flaky > 35 Not recommended for sealing

Flaky 26 to 35 0 to - 0.01

Angular 15 to 25 Nil

Cubic < 15 + 0.01

Rounded NA 0 to + 0.01

Not crushed Rounded NA + 0.01

Table 2.2: Adjustment to Basic Voids Factor for Traffic Effects (Vt)

Traffic

Adjustment to Basic Voids Factor (L/m2/mm) Flat or downhill Slow moving – climbing lanes

Normal Channelised* Normal Channelised* On overtaking lanes of multi-lane rural roads where traffic is mainly cars with ≤10% of HV

+0.01 0.00 N/A N/A

Non-trafficked areas such as shoulders, medians, parking areas

+0.02 N/A N/A N/A

0 to 15% Equivalent Heavy vehicles (EHV)

Nil -0.01 -0.01 -0.02


-0.01 -0.02 -0.02 -0.03


- 0.02 - 0.03 - 0.03 - 0.04**

> 45% Equivalent Heavy vehicles (EHV)

- 0.03 - 0.04** - 0.04** - 0.05**

5

Australian Asphalt Pavement Associa�on Australian Asphalt Pavement Associa�on



Embedment allowance



Basic voids


ALD

Design voids


Basic binder application rate:

Bb


Bd

Step 4 – Determine design voids factor VF

VF = Vf + Va + Vt   Is VF outside of upper & lower

limits?

Step 5 – Basic binder applica�on rate Bb

Bb (L/m2) = VF x ALD


Design Input Data - Aggregate

  Average Least Dimension – May use typical values for ini�al design

  Need values for lot to be used for final design

7mm 3.5 – 4.5 mm

10mm 5.0 – 6.0 mm

14mm 7.5 – 9.0 mm

20mm 10.5 – 12.0 mm


Polymer Modified Binder & Emulsion Seals

  Apply a Polymer Factor (PF) varies with PMB & type of seal   Add normal allowances   Aggregate design spread rate:

–  10% heavier than normal

  Emulsion seals – replace PF with EF

Step 5 – Modified Basic binder applica�on rate Bbm

Bbm (L/m2) = VF x ALD x PF

6



Embedment allowance



Basic voids


ALD

Design voids



Bb


Bd

Step 6 – Design binder applica�on rate Bd

Bd = Bb + As + Ae   Round to nearest 0.1 l/m2


Allowances (L/m2)   As -‐ Surface texture

–  Sand patch texture depth (mm)

  Ae -‐ Aggregate embedment –  Ball penetra�on test – Nega�ve allowance

  Absorp�on of binder by: –  pavement –  aggregate (not common)

Allowances are cumula�ve


Sand patch test – 50cc spread uniformly to calculate texture in mm – determine AS allowance from Table

Aggregate size of proposed

seal

Measured texture depth

(mm)

Surface texture allowance (L/

m2)

Aggregate size of proposed

seal

Measured texture depth (mm)

Surface texture allowance (L/m2)

Existing: 14, 16 or 20 mm seal Existing: 5 or 7 mm seal

5 or 7 mm

0 to 0.3 Note 1

5 or 7 mm

0 to 0.3 Note 1 0.4 to 0.6 Note 2 0.4 to 0.9 +0.1 0.7 to 0.9 +0.1 1.0 to 1.5 +0.2 1.0 to 1.3 +0.2 1.6 to 2.2 +0.3 1.4 to 1.9 +0.3 2.3 to 3.2 +0.4 2.0 to 2.9 +0.4 >3.2 +0.5

>2.9 +0.5

10 mm

0 to 0.3 Note 1

10 mm

0 to 0.3 -0.1 0.4 to 0.7 +0.1 0.4 to 0.5 0 0.8 to 1.1 +0.2 0.6 to 0.7 +0.1 1.2 to 1.8 +0.3 0.8 to 0.9 +0.2 >1.8 Note 3 1.0 to 1.3 +0.3

14 mm

0 to 0.2 Note 1 1.4 to 1.8 +0.4 0.3 to 0.6 +0.1

>1.8 Note 3 0.7 to 0.9 +0.2

14 mm

0 to 0.3 -0.1 1.0 to 1.4 +0.3 0.4 to 0.5 0 1.5 to 2.0 +0.4 0.5 to 0.6 +0.1 >2.0 +0.5 0.6 to 0.7 +0.2 Existing: asphalt/slurry surfacing 0.8 to 0.9 +0.3

All

0 to 0.1 0 1.0 to 1.3 +0.4 0.2 to 0.4 +0.1 1.4 to 1.8 +0.5 0.5 to 0.8 +0.2

>1.8 Note 3 0.9 to 1.4 +0.3 Existing: 10 mm seal >1.4 +0.4

5 or 7 mm

0 to 0.3 Note 1

Notes:

Embedment considerations dominant

Specialised pre-treatments may be necessary

This treatment might not be advisable depending on the shape and interlock of aggregates so alternative treatments (surface enrichment, small size seal or others) should be considered

For application of aggregate sizes greater than 14 mm, adopt allowances applicable to 14 mm aggregate.

0.4 to 0.9 +0.1 1.0 to 1.4 +0.2 1.5 to 2.0 +0.3 2.1 to 2.7 +0.4

>2.7 +0.5

10 mm

0 to 0.3 Note 1 0.4 to 0.7 +0.1 0.8 to 1.1 +0.2 1.2 to 1.7 +0.3

>1.7 Note 3

14 mm

0 to 0.2 Note 1 0.3 to 0.6 +0.1 0.7 to 0.9 +0.2 1.0 to 1.2 +0.3 1.3 to 1.7 +0.4

>1.7 Note 3

Surface texture allowance takes into account   Exis�ng surface

  Proposed seal

Gives us warnings about our seal selec�on


Allowances (L/m2)

  As -‐ Surface texture – Sand patch texture depth (mm)

  Ae -‐ Aggregate embedment – Ball penetra�on test – Nega�ve allowance

  Absorp�on of binder by: – pavement – aggregate (not common)


Ae – Aggregate Embedment Allowance

0

1

2

3

4

0 1000 2000 3000 4000 5000

Traffic volume (vehicles/lane/day)

Bal

l pen

etra

tion

(mm

)

Nil

-0.1 L/m2

See note

-‐ 0.2 l/m2

7


Allowances (L/m2)   As -‐ Surface texture

– Sand patch texture depth (mm)

  Ae -‐ Aggregate embedment – Ball penetra�on test – Nega�ve allowance

  Absorp�on of binder by: – pavement – aggregate (not common)




Embedment allowance



Basic voids


ALD

Design voids



Bb


Bd

Step 6 – Design binder applica�on rate Bd

Bd = Bb + As + Ae   Round to nearest 0.1 l/m2

Reality Check Will this work considering

  The condi�ons at �me of placement

  The resources that will be available

  The traffic stresses


Double/double Seal Design

Design method applies if both applications applied within 24 hours



  First Application (larger aggregate)

– Vf1 reduced as voids are partly filled by smaller aggregate

– Solid line in Figure 2.1 & 2.2 (Update to D/D design)

– Same adjustments & allowances as single/single design added



  Second Application (smaller aggregate)

– Vf2 dotted line in Figure 2.1 & 2.2 (Update to D/D design)

– Same process as single/single design

– BUT NO ALLOWANCES for   Surface texture   Embedment   Pavement absorption


Basic Voids Factor Vf for D/D Seal 0 – 500 v/l/d

8


Basic Voids Factor Vf for D/D Seal 500 – 15000 v/l/d


Geotextile Reinforced Seals

Design procedure 1.  Seal design as described

2.  Add fabric reten�on allowance AR

(for a 140g/m2 ~ 0.9 L/m²)

3.  Appor�on binder to bond coat Bond coat -‐ 0.6 L/m2

4.  Second applica�on of binder Total minus bond coat applica�on (e.g. 2.8 – 0.6 = 2.2)

Hot day + heavy bond coat rate + traffic on a bare geotex�le Aggregate spread rate (m²/m³)

  Calculated from ALD of aggregate   Spread rate (ASR) in m²/m³   General work = 900/ALD

– varies for traffic and type of binder –  ranges from 900/ALD to 750/ALD –  in prac�ce, designed to nearest 10 m²/m³

Example of S/S seal design

Site Details Traffic   2 lanes, each 3.6m   AADT – 800   % EHV = 10% Exis�ng surface   Aggregate: 10mm   Texture: 1.2mm   No cracking Proposed Reseal: 14mm

Binder: C170


Step 1 – Input Informa�on   Design Traffic

–  For 2 lanes = ½ AADT –  DT = ½ x 800 = 400 v/l/d –  EHV = 10%

  Aggregate –  Crushed –  FI -‐ 22% –  ALD – 8.5mm

9

Example of S/S seal design Step 2 – Determine Vf

Vf = 0.18 L/m2/mm


Step 3 – Adjustments for aggregate & traffic   Va – Table 2.1

–  FI – 22% –  Va = 0

  Vt – Table 2.2 –  EHV = 10% –  Road geometry – –  Vt = 0

flat, not channelised


Step 4 – Determine design voids factor VF   VF = Vf + Va + Vt

–  Vf = 0.18 –  Va = 0 –  Vt = 0

VF = 0.18 L/m2/mm

Step 5 – Calculate basic binder rate Bb   Bb = VF x ALD = 0.18 x 8.5

Bb = 1.53 L/m2

Example of S/S seal design Step 6 – Calculate design binder rate Bd   Bd = Bb + As + Ae

–  No embedment. Ae = 0

–  Surface texture = 1.2mm

–  As = 0.3 l/m2

Bd = 1.53 + 0.3 = 1.8 L/m2

(round to nearest 0.1L/m2)

Loose aggregate spread rate for C170, 320, multigrade

Traffic conditions Aggregate Spread Rate (m2/m3)

Traffic > 200 v/l/d

900 / ALD

Very low traffic ≤ 200 v/l/d

850 / ALD

Spread Rate = 900/8.5 = 105 m2/m3

Documents

Priming - aapaq.org · Flakiness index Traﬃc Vt Table 2.2 Heavy vehicles Climbing lanes Channelised lanes Table 2.1: Adjustment to Basic Voids Factor for Aggregate Shape (Va) Aggregate