Bio-based Additives for Asphalt Applications & Pavement ......EFFECT OF ASPHALT AGING •Pavements...

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Cargill, to or by those employees who do not have a need to know is prohibited except as authorized by Cargill in writing.

© 2013 Cargill, Incorporated. All rights reserved.www.cargill.com

Hassan A. Tabatabaee, Ph.D.Cargill Industrial Specialties

Bio-based Additives forAsphalt Applications & Pavement Preservation

© 2015 Cargill, Incorporated. All rights reserved.AnovaTM Asphalt Solutions

Cargill’s Role in Asphalt• Cargill is a large, global provider of

solutions in agricultural, food, financial

and bio-industrial markets.

1. Cargill Anova™ Modifiers

2. Cargill Anova™ Rejuvenators

3. Cargill Anova™ Green Diluents

4. Cargill Anova™ Anti-strips

5. Cargill Anova™ WMA

6. Cargill Anova™ Emulsifiers

3


Agenda

•Background on Rejuvenation

•Application Categories:

1. Rejuvenated High-Recycled HMA

2. Rejuvenating Pavement Preservation

3. Rejuvenating Cold Patch

4. Rheology Modifiers

•Conclusions

4


Components in Hot-Mix Asphalt

• Aggregate

– Load carrying component in mix

• Asphalt binder

–Binds aggregate together

–Waterproofs

• Air voids

–Allows for expansion of asphalt binder

–Allow for compaction under traffic

•As-built 6 - 8% voids

•After traffic 3 - 5% voids


IntroductionEFFECT OF ASPHALT AGING

• Pavements age from the surface, downwards

• Aging is affected by rate of air permeability (porosity),

climate conditions, UV, etc.

• Aged bitumen is more brittle and less durable.

• Flaws can quickly become crack initiation points,

and eventually water penetration points.

• Excessive use of aged reclaimed asphalt pavement

(RAP) can impart same properties to new

pavements.

• An engineered solution is needed…

5


What is rejuvenation?• “Rejuvenation” is an inaccurate, but popular term.

• Rejuvenators do not undo oxidative aging!!!

• A good rejuvenator reverses the impact of aging on asphalt,

reactivating the bitumen, to restore performance, and durability.

• Reduce modulus/viscosity

• Restore balance of asphalt fractions

• Restore phase/colloidal stability

• Reduce brittleness / improve damage resistance

• Restore “healing” ability

• Equal (or better) aging behavior than original binder!

Softening Reju

ve

natin

g

6


Simplified Bitumen Colloidal Model

7

Unaged Bitumen - Stable

Low Polarity Aromatic Oil

Asphaltene

Resins



8

Aged – Loss of softer fractions


Asphaltene

Resins



9

Aged – Forming Rigid Structures


Asphaltene

Resins



10


Asphaltene

Resins

After Ideal Rejuvenation…

Ideal

Rejuvenator


Material Considered in this Presentation

The Rejuvenator:

The Asphalt Binders Considered:• RAP contents ranging from 30 to 85% by weight of mixture.

• Base binders ranging from XX-34 to PG64-22, as well as

pen grades 40/50, 50/70, and 70/100.

• All are dense graded surface and base course mixes.

• All DCT tests done at climatic PG+10 temperature.

• All IFIT and Overlay tests done at 25C.

Description Flash Point Viscosity at 60°C

Chemically Modified Veg oil-

based Rejuvenator

>290°C 28.5 mPa.s

TFO Mass loss TFO Visc Ratio

<1% 1.1

7


Rejuvenated High-Recycled HMA

6


The Potential of high RAP Rejuvenation…

13

31% RAP 40% RAP 45% RAP

50% RAP 67% RAP 100% RAP


The allowable RAP dosage is often estimated using a

blending chart in accordance to PG, R&B, or Pen Grade

Bitumen Design

Extraction &

Recovery

High and Low

Temperature

Penetration

Softening Point FRAASS


Adjusting Performance using Rejuvenator Dosage

15

Anova™ Rejuvenator Dosage (%)

Fracture Energy of 61% Recycled HMA

using Anova™ Rejuvenator

Pen 160-220

(No Anova)

Pen 70-100 + Anova™

• Normal paving grade bitumen +

rejuvenator can perform better

than soft bitumen / flux.


2.9

3.8

1.7

2.8

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

APA Rut Depth (mm) Field Cores

Example #2:

16

22% RAP39% RAP +

24% RAS +

Rejuvenator

45% RAP 45% RAP +

Anova Rej45% RAP +

22%RAS

45% RAP +

22%RAS +

Anova Rej

• Rejuvenation resulted in a high

improvement in durability, with minimal

impact on rutting.

© 2015 Cargill, Incorporated. All rights reserved.AnovaTM Asphalt Solutions17

Fracture Energy

Example #3: 100% RAP HMA

Rejuvenated 100% RAP

Permanent Deformation

• HMA solely consisted of RAP and

Rejuvenator

• Rejuvenator sufficiently activated RAP to

achieve +500 J/m2 fracture energy.

• No rutting issues observed.


0

1

2

3

4

5

6

7

8

9

10

50 75 100 125 150

Air

Vo

ids

(%

)

Compaction Temperature (°C)[Plant Produced 9.5mm Surface Course]

50% RAP + Anova™

30% RAP

Improved Compaction with Proper Rejuvenation

• Use of the rejuvenator significantly improved the

Compactability, even after a 20% increase in RAP

content.

– A 25°C improvement in compaction temperatures achieved

– No over-compaction at hot mix temperatures.

95°C25°C

120°C


Bio-based Rejuvenating Pavement Preservation

6


Pavement PreservationIts all about timing!

Service Life (Years)

Pavem

en

t C

on

dit

ion

$$ $$ $$

$$ $ $

$$$$$ $$$$$


Rejuvenating Fog Seals

21

Before 0 hrs

4 hrs 24 hrs

•A truck mounted spray system is

used to apply product at

predetermined treat-rate:

–Often in range of 0.005-0.05

GAL/yd2 depending on product

type

“Sanding” can be

used for rich

application points

and to boost friction.


Surface treated

The photo clearly shows

lighter weathering,

longitudinal cracking and

alligator cracking.

Untreated control surface

The photo clearly shows

accelerated weathering,

further defined and

development of longitudinal

cracking and alligator cracking.

Examples of asphalt preserver photos


Rejuvenating Scrub Seals

Functions of a Rejuvenating Scrub Seal

• Fill existing cracks with a tough polymer-modified emulsion.

• Provide a durable wearing surface.

• Surface rejuvenation over time

Polymer modified rejuvenating emulsion (CMS-2P)Well-graded aggregate cover


Cover manhole

Sweep dirt

and debris

Rejuvenating

emulsion spraying

and scrubbing

Bio-based Rejuvenating Scrub Seal

6


Chip application

and rolling

Bio-based Rejuvenating Scrub Seal

6


Bio-based Rejuvenating Cold Patch Additive

26


What is Cold Patch?

• Cold mix asphalt mixture for use in patching and leveling

applications.

• Sold in bulk, or in bags and buckets

• Used for temporary or permanent patching jobs.

• Temporary patch is used in large cities to cover construction

jobs during the day.

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• A good cold patch will have these properties:

– Good storage and stockpile life

– Good stripping resistance.

– Good workability and compaction without need for heating

– Resistant to pull out or rutting


Rotterdam, Netherlands

How is it incorporated?

29

• If no bitumen is to be used in the cold

patch, method will depend on

necessity of drying the RAP:

RAP Dryer

with indirect

hot oil heating

Extended

chamber for

rejuvenator

blending

Rejuvenator

sprayed at entry

to mixing

chamber


Bio-based Rheology

Modification


Bio-based Rheology ModifierRHEOLOGY MODIFIER FOR ASPHALT BINDER

6

PG 64-22

Bio-based

Modifier0.5-5%

wt.

BlendPG 58-28

Needs to have following

properties:

• High bitumen

compatibility

• Good miscibility and

simple blending

• Good aging and thermal

stability

• Good polymer

compatiblity

• Produce stable emulsion


Performance Grade and Rheology

ModifiersENHANCING LOW QUALITY BITUMEN: IMPROVED CRACKING RESISTANCE

• Increases UTI of bitumen through higher softening at lower temperatures without

sacrificing the high-end temperature

• High impact at low dosage rate (2-3% by weight of binder)

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• Significant improvement of PMB

workability, without significant loss of

elastic recovery, when additive added to

finished PMB

33

Improve Workability of PMB

0%

2%

4%

6%

8%

10%

12%

14%

PG64V-22 PG58H-34 PG76V-28 PG82V-22

1.4 Pa.s 1.0 Pa.s 2.0 Pa.s 6.1 Pa.s

Ch

ange

in V

isco

sity

per

1%

An

ova

10

05

(%)

PMB TypeViscosity at 135C (Pa.s)

Visc@135C Visc@150C

Average

Average


Conclusions

• Bio-based material, such as from modified vegetable oil

sources, can be used to produce compatible and high-

performing rejuvenation and rheology modification

additive for asphalt and pavements.

• Bio-based rejuvenator dosage can be used as the design

property in Performance-based design methodology.

• Proper bio-based rejuvenation can be used as a

preventive measure to preserve pavement functionality.

• Bi-based cold patch formulations can utilize up to 100%

recycled asphalt content to produce cold mixes and patch

material.

34


REFERENCES:

• Tabatabaee, H.A. and Kurth, T.L., “Rejuvenation vs. Softening:

Reversal of the Impact of Aging on Asphalt Thermo-Rheological and

Damage Resistance Properties,” Proceedings of the International

Society for Asphalt Pavers, 2016, Jackson, WY, USA.

• Andrew Hanz & Gerald Reinke, “Performance of Bio-modified

Rejuvenation Scrub Seal” International Symposium on Asphalt

Emulsion Technology, Nov 2016

• Tabatabaee, H.A. and Kurth, T.L., “Critical Comparison Of Asphalt

Recycling Agents From Bio-based and Petroleum Sources,”

Proceedings of the 22° Encandro de Asfalto, 2016, Rio de Janeiro,

Brazil.

• Tabatabaee, H.A. and Kurth, T.L., “Analytical Investigation of the

impact of a novel bio-based recycling agent on the colloidal stability

of aged bitumen,” Proceedings of EATA 2017, Switzerland.

8


Hassan Tabatabaee, Ph.D.

[email protected]

mailto:[email protected]

Bio-based Additives for Asphalt Applications & Pavement ......EFFECT OF ASPHALT AGING •Pavements...

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