E Experiences with SBR and SBS modified i ith SBR d SBS difi d - - PowerPoint PPT Presentation

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E Experiences with SBR and SBS modified i ith SBR d SBS difi d binders in the construction of seals in RSA JG L JG Louw/TR Distin /TR Di ti Cost effective high performance surfacings performance surfacings Overview Use of modified

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SLIDE 1

E i ith SBR d SBS difi d Experiences with SBR and SBS modified binders in the construction of seals in RSA

JG L /TR Di ti JG Louw/TR Distin Cost effective high performance surfacings performance surfacings

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SLIDE 2

Overview

f f

  • Use of modified binders in RSA
  • Properties of SBR and SBS modified binders
  • Storage stability during handling
  • Storage stability during handling
  • Application techniques for spray seals
  • Design of modified binder spray seals

Design of modified binder spray seals

  • Summary

www.arrb.com.au

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SLIDE 3

Modified bitumen usage in Seals g

  • < 1982 - mainly SBR and natural latex in anionic emulsions
  • 1982

Bitumen rubber

  • 1982 - Bitumen-rubber
  • 1984 - SBR latex in hot bitumen
  • 1989 - SBR latex in cationic emulsions
  • 1990 - SBS polymer in hot bitumen

44% 8% 16% penetration cutback em ulsion 2% 10% 20% SBS SBR Rubber

www.arrb.com.au

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SLIDE 4

SBS block co-polymer

Ordered molecular structure

SBR (latex)

Random molecular structure Random molecular structure

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= styrene = butadiene

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SLIDE 5

P l t d i Polystyrene domain Polystyrene domain Butadiene chain Butadiene chains

B h d SBS Linear SBS Branched SBS

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SLIDE 6

Softening Point of SBR vs SBS g

(80/100 pen base bitumen)

110 90 100 (deg C) 60 70 80 ning Point SBS SBR 40 50 60 1 2 3 4 5 Softe 1 2 3 4 5 Polymer content (%m/m) www.arrb.com.au

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SLIDE 7

Viscosities – SBR vs SBS

(80/100 pen base bitumen)

900 600 700 800

mPa.s)

3% SBR

200 300 400 500

Viscosity (m

3% SBS 80/100

100 200

130 140 150 160 170 180 190 200 210 V 130 140 150 160 170 180 190 200 210 Temperature (deg C)

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SLIDE 8

Elastic Recovery – SBR vs SBS y

(80/100 pen base bitumen)

90 75 80 85 90 deg C (%) 60 65 70 75

  • very @ 15

3% SBR 3% SBS 40 45 50 55 lastic Reco 40 5 10 15 20 Temperature (deg C) El www.arrb.com.au

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SLIDE 9

1 40 1.60 0.80 1.00 1.20 1.40 sion J/cm2 3% SBR 80/100

Cohesion

0.00 0.20 0.40 0.60 Cohes 3% SBS

properties @ 5°C

Tensile Properties – NF EN 13587

10 20 30 35 40 45 50 60 Temperature (deg C)

Tensile Properties NF EN 13587

Initial length = 50 mm Unit 80/100 3% SBR in 80/100 3% SBS in 80/100 At break: At break: Elongation Stress % MPa 339 0,06 >900 0,59 >900 0,68

Deformation Energy Properties – NF EN 13703

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  • gy
  • p

s 3 03

At break: Mean energy J/cm2 9,6 24,1 29,1

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SLIDE 10

Storage Stability at application g y pp temperature

70

Ring and Ball Softening Point

1200

Dynamic Viscosity

10 20 30 40 50 60 70 & B Soft Point (deg C)

SBR (200 deg C) SBS (180 deg C)

200 400 600 800 1000 1200 Viscosity @ 135 deg C (mPa.s)

SBR (200 deg C) SBS (180 deg C)

10 R & 5 11 13 16 18 Time after manufacture (hrs) V 5 11 13 16 18 Time after manufacture (hrs) 40 50 60 70 80 ecovery g C (%)

Elastic Recovery

10 20 30 40 Elastic Re @ 15 deg 5 11 13 16 18 Time after manufacture (hrs)

SBR (200 deg C) SBS (180 deg C)

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( )

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SLIDE 11

Typical modified binder seals yp

Single Seal Double Seal

EXISTING SUBSTRATE EXISTING SUBSTRATE

Split Seal Cape Seal

EXISTING SUBSTRATE EXISTING SUBSTRATE

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SLIDE 12

Typical application rates

Aggregate

Single seal 13,2 mm aggregate (ALD = 8,2)

Traffic (ELV) 5000 1000 > 20000 Spread rate (m3/m2) Bi d li ti t (l/

2) h t

Binder application rate (l/m2) hot 3% SBR + 80/100 1,65 1,24 1,15 90 – 100 3% SBS + 80/100 1,78 1,34 1,20 90 – 100 Cationic Spray Grade 70% + 5% latex 1,68 1,27 1,13 90 – 100

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5% latex

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SLIDE 13

Spray rate ajustment factors – TRH 3 p y j

SBR modified bitumen T ffi ( l ’ ) Si l S l D bl S l S li S l Traffic (elv’s) Single Seal Double Seal Split Seal < 5000 1,3 1,1 1,2 5000 – 20000 1,2 1,0 1,1 5000 0000 , ,0 , > 20000 1,1 1,0 1,0 SBS modified bitumen < 5000 1,4 1,2 1,3 5000 – 20000 1,3 1,1 1,2 > 20000 1,2 1,0 1,1 > 20000 1,2 1,0 1,1

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SLIDE 14

Construction of seals

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SLIDE 15

Use of cutters

  • General resistance amongst practitioners
  • No cutters allowed on National Route contracts

When used with discretion excellent results

  • When used with discretion – excellent results
  • Generally not more than 4% cutter used
  • Cutback SBR marginally less temperature sensitive
  • Cutback SBR marginally less temperature sensitive

than SBS PMB’s

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SLIDE 16

Semi-priming polymer modified binder p g p y

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SLIDE 17

Summary

  • With the increase in traffic and rapid ageing of the

South African national & provincial road network South African national & provincial road network have lead to 70% of all reseals being constructed using modified binders

  • Practitioners recognise the improved life cycle

costs associated with the use of these binders Th i d f ti f SBS

  • The improved performance properties of SBS vs

SBR modified binders have resulted in an increase demand for SBS modified binders

www.arrb.com.au

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