“WINTER SEALS” WORKSHOP THE SUPPLIERS · PDF fileROAD OVERNIGHT Bitumen rubber...

4

“Winter Sealing”

Pretoria10 April 2014

Johan MullerIn conjunction with Kobus Louw

OVERVIEW

• Supply & Demand

• Impact on Availability of Products

• Impact on Availability of Services

• Seasonal Indexes

• Winter Seal Product Characteristics

• Health Safety & Environment

HISTORICAL SUPPLY (PROJECTED)

THEORETICAL SUPPLY & DEMAND

SUPPLY & DEMAND

IMPACT ON AVAILABILITY OF PRODUCT

• Bitumen supply shortfalls

• Imported Bitumen

– Price

– Logistics

• Secondary product availability

• Anything is possible but not always practical

• Careful planning required.

SEASONALITY

• Why is there a seasonality?

• Seasons (Autumn & Winter & Spring)

• RSA Summer Holiday Break

• Budget / Spending Cycle

• Embargo Periods

• Lack of planning (common sense)

• Knowledge base

WEATHER LIMITATIONSGRADE TEMPERATURE

ROAD OVERNIGHT

Bitumen rubber 25°C ? °C

Bitumen rubber (Winter Grade) As spec by project spec

SBS SBR (ex 80/100) 25°C ? °C

80/100 25°C ? °C

SBS or SBR (ex 150/200) 21°C ? °C

SBS or SBR (Winter Grade) As spec by project spec

150/200 21°C ? °C

MC3000 10°C ? °C

MC800 10°C ? °C

Bitumen Emulsions 10°C ? °C

Modified Bitumen Emulsion 10°C ? °C

Guidelines COLTO 4300-8

• Supply & Demand for Sprayers

• Cost of fleet

• Staff complement employment

• Hardware Utilization

• Human Capacity Utilization

• Maintenance

• COF’s (Roadworthiness)

• Calibration & Certification (Koedoespoort)

IMPACT ON AVAILABILITY OF SERVICES

• Supply & Demand for Sprayers

• Cost of fleet

• Staff complement employment

• Hardware Utilization

• Human Capacity Utilization

• Maintenance

• COF’s

IMPACT ON AVAILABILITY OF SERVICES

Options?

• Go to a softer grade

– 80/100 → 150/200 → MC3000

• Cut back with various cutters (Permitted?)

• Guidelines COLTO 4300-1

• Guidelines TRH3 p52 and APPENDIX I p 209

• Use cold applied products EMULSIONS

WHAT IF TEMPERATURES ARE BELOW?

Hot-applied binders(penetration grade bitumen)

Typical cold weather stripping

Note how little binder is attached tothe aggregate

Guidelines COLTO 4300-8

Grade ROAD

TEMPERATURE

AIR

TEMPERATURE

OVERNIGHT

TEMPERATURE

80/100 25°C ? ?

150/200 21°C ? ?

MC3000 10°C ? ?

MC800 10°C ? ?

GO TO SOFTER GRADE

• Why do we cut back?

– Temporary reduction of viscosity

– Ensure wetting

– Volatile cutters evaporate

– Residual binders revert to original seal grades

– Promote early mosaic formation during compaction (re-orientation) allowing road stone embedment

CONSIDER CUT BACK OPTION

BASED ON NATREF 80/100 TRH3 p52 and APPENDIX I p 209

OVERNIGHT

TEMP

ROAD

TEMP

APPROXIMATE

AIR TEMP

% CUTTER SPRAY

TEMP

>12 > 48 >31 0 150 – 175

9 – 12 40 – 48 26 – 31 2 – 1 132 – 149

6 – 9 32 – 40 21 – 26 4 – 3 121 – 138

3 – 6 24 – 32 16 – 21 7 – 5 115 – 135

0 – 3 16 – 24 10 – 16 9 – 7 100 – 118

< 0 NO SEAL WORK RECOMMENDED

Engineers’ call

CUT BACK GUIDELINE FOR BITUMEN

Determination of the quantity of cutter (fluxant) required

Effect of fluxant on bitumen properties on 70/100 pen bitumen

Property

% Paraffin (volume/mass) Specification

Penetration (0,1 mm) 70 110 145 185 251 70 – 100

Softening Point (°C) 48,8 45,1 42,9 40,1 38,6 42 - 51

Visc @ 60 °C (Pa.s) 153 115 72 51 32 > 75

Visc @ 135 °C (Pa.s)0.31 0.24 0.21 0.17 0.15 0,15 – 0,40

Minimum road surface temperature require to retain aggregate (°C)

25 23 21 19 18 -

70/100 pen bitumen @ 20 °C

70/100 pen bitumen @ 27 °C

The effect of fluxing on the

adhesion properties of bitumen

70/100 pen bitumen (unfluxed)

20 °C

70/100 pen bitumen + 3% paraffin

20 °C

70/100 pen bitumen + 5% paraffin

20 °C

Hot-applied Modified Binders(PMB’s & Bitumen Rubber)

Fluxing of S-E2Viscosity vs. Temperature

0

200

400

600

800

1000

1200

140 150 160 170 180 190

Vis

cosi

ty (

mP

a.s)

Temp (°C)

70/100

0% flux

2% flux

3% flux

4% flux

5% flux

Effect of fluxant on properties of S-E2 polymer modified binder

Property

% Paraffin (volume/mass) Recommendation(TG 1)

0 2 3 4 5

Penetration (0,1 mm) 65 99 124 145 190 No spec

Softening Point (°C) 63 54 53 52 51 60 – 80

Viscosity @ 165 °C (Pa.s) 401 331 292 270 227 0,60 max.

Elastic Recovery @ 15 °C (%)81 83 85 83 80 > 70

Minimum road surface temperature require to retain aggregate (°C)

25 23 21 20 18 -

?

Comparison 70/100 vs S-E2(fluxed properties)

Property% Cutter

Penetration (0,1 mm)

70/100S-E2

7065

11099

145124

185145

251190

Softening Point (°C)

70/100S-E2

48,863,0

45,154,0

42,953,0

40,152,0

38,651,0

Conventional Bitumen RubberCriteria more user friendly bitumen rubber product:• Reduce temperature required to manufacture and apply

– from ~ 200°C to < 180°C

• Reduce viscosity to accommodate reduction in temperature• Maintain or improve toughness levels of the product• Maintain or improve elastic response of the product• Improve / increase the shelf-life of the product• Reduce sensitivity to time and the ever-changing physical

properties of the product• Reduce asphalt mixing or spray application temperatures• Reduce sensitivity to temperature • Remove requirement of compaction at high temperatures

Typical cutter properties

Solvent Paraffin Medium flash point solvent

High flash point solvent

Properties

Flash Point (°C), min 38 62 89

IBP (°C), min 150 180 217

Dry Point (°C), min 252 288 241

Aromatics (%m/m) 18 17 19

Cutter selection will vary depending on the suppliers’ proprietary technology

PROPERTIES OF BITUMEN-RUBBER CUT BACK WITH VARYING QUANTITIES OF HIGH BOILING POINT SOLVENT

PROPERTY% HYDROCARBON CUTTER

S-R1 SPEC

R & B Softening Point (°C) 61,3 49,1 44,7 41,2 41,0 55 – 62

Resilience (%) 42 3 - - - 13 – 35

Flow @ 60 °C (mm) 20 105 127 134 147 15 – 70

Dynamic viscosity @ 190 °C (dPa.s)

34 26 19 14 9 20 - 40

Minimum recommended road surface temperature recommended to retain aggregate

25 22 - 23 20 -21 18 - 19 16 - 17 -

HEALTH SAFETY & ENVIRONMENT

• Occupational Health Safety ACT

• Injuries are costly

– Person

– Families

– Companies

– Workmen’s compensation

• Loss of Productivity

• Sabita safety training

S-E 1 + 3% Fluxant (160 °C)

S-E 1 + 3% Fluxant (160 °C)

S-E 1 + 3% Fluxant (160 °C)

Picture of exploded sprayer

Guidelines in COLTO 4300-8

Grade ROAD

TEMP

AIR

TEMP

OVERNIGHT

TEMP

80/100 25 ? ?

150/200 21 ? ?

MC3000 10 ? ?

MC800 10 ? ?

Bitumen Emulsions 10 ? ?

Modified Bitumen Emulsion 10 ? ?

COLD APPLIED ALTERNATIVES

What is a Bitumen Emulsion?

COLD APPLIED ALTERNATIVES

50 microns

50

mic

ron

s

Microscopic image – bitumen emulsion x 1000

+

+ +

+

+

+

+

+

+++

+

+

+

+

+

+

Cationic Spray Grade(CRS)

Bitumen droplet

0,20 to 0,30% emulsifier

+

-

Anionic Stable Grade (SS)

+++

-++

1,0 to 1,5% emulsifier

-

-

-

- -

-

-

-

-

-

- -

- --

-

- -

-

-

-

-

--

-

- -

- -

-

-

Grades of Bitumen Emulsions

Spray Grade / Rapid Set

Mix Grade / Medium Set

Stable Grade / Slow Set

R

M

S

COLD APPLIED ALTERNATIVES

• Emulsions & modified emulsions can also be used to construct single & double seals

• Different construction approach will be required.

i.e.:

Single seal 1st spray a tack application

stone application

2nd spray a penetration application

Double seal stone application

3rd spray a penetration application

COLD APPLIED ALTERNATIVES

Latex modification of bitumen

Bitumen emulsion SBR(Styrene-Butadiene-Rubber)

+

Microscopic image – bitumen emulsion + 5% latex (1000 x)

50

mic

ron

s

50 microns

Microscopic image – rubber latex (1000 x)

50

mic

ron

s

50 microns

• Emulsions

– CRS60 {or CRS60(t)}

– CRS65 {or CRS65(t)}

– CRS 70 (made to order)

• Modified emulsions

– CRS60 / 3,5 (made to order)

– CRS65 / 3,5 (made to order)

– CRS 70 / 3,5 (made to order)

• Fog Sprays

– CRS 60 / 65 (Cationic)

– SS 60 (Anionic)

Notify Suppliers in time6-8 weeksDelivery of

Raw Material

COLD APPLIED ALTERNATIVES

Coalescence – different stages

Stable emulsion Flocculation Densification Coalescence

Fluxants promote development of coalescence

Coalescence – different stages

“Fluxing” of bitumen emulsions

For Cape Seals NO FLUX recommended!

REQUIREMENT FOR FLUXING AGENTSSANS 4001-BT4 (Edition 1) (old SABS 548:2003)

Fluxing agents shall, when tested in accordance withMethod ASTM D86, comply with the following requirements:

(a) Initial boiling point: Not lower than 140 °C

(a) Distillate at 350 °C: Not less than 90% (v/v)

THIS PREVENTS SUPPLIERS TO INCORPORATE “ANY” SOLVENTS

Determination of flux content (ASTM D244)

Determination of flux content (ASTM D244)

Determination of flux content (ASTM D244)

Determination of flux content (ASTM D244)

Typical fluxant levels used in the Western Cape

November to February

March to April to May

June to AugustSeptember to

October

2% 3% 4 – 5% 3%

Effect of fluxing on bitumen emulsions

• Improves dispersion

• Improves the “breaking” rate

• Quicker mosaic formation

• Improved viscosity

• Enhanced storage stability

Disadvantages of unfluxedbitumens

• Poorer dispersion

• Poorer storage stability

• Slower mosaic formation

• Lower viscosity

• Delay in breaking during cold weather conditions

Sedimentation of bitumen particles

STOKES FORMULA

V =2

9

gr

2

(D-d)

η

Where:

V = rate of settlement

g = acceleration gravity

D = density of dispersed phase

d = density of dispersion medium

r = radius of particles

η = viscosity of aqueous phase

Densities of fluxed bitumen

0.980

0.985

0.990

0.995

1.000

1.005

1.010

1.015

1.020

1.025

0 1 2 3 4 5 6 7 8 9 10

De

nsi

ty (

kg/l

)

Paraffin flux (%m/m)

Freezing/Thawing of emulsions