Experience of polymer modified bitumen and emulsion … of... · • To demystify Bitumen, asphalt and related technologies. ... 70/100 Softening Point Rutting 50/70 Ageing, Deformation

Presented by:

Experience of polymer

modified bitumen and

emulsion on pavement

construction in Kenya

Charles Lang’atAsphalt Institute of East Africa

International Transport and Road Research Conference (iTRARR 2018)

INTRODUCTION

• Based in Nairobi, Kenya

• Training in Asphalt technology

• Research and Development

• Lab Test Services

• Pavement Design Services

Primary Focus • To demystify Bitumen, asphalt and related technologies.

• To develop capability, capacity in construction techniques

• To innovate home grown solutions for Africa pavements.

ABOUT AIEA


INTRODUCTION

Bitumen Roads in Kenya - History

Class Premix SD Gravel Earth Total

Trunk (A) 1,245 1,564 715 94 3,618

National (B) 350 1,166 819 346 2,681

Primary (C) 643 2,198 3,602 1,553 7,996

Secondary (D) 77 1,183 5,702 4,088 11,050

Minor (E) 166 542 8,216 17,983 26,907

Special Purpose 25 115 4,930 6,254 11,324

All classes 2,506 6,768 23,984 30,318 63,576

Candidates for PMB and PME: 7,706km


INTRODUCTION

• Primary Binders currently in use in Kenya

• Penetration Grade Bitumen• 80/100: now 70/100

• 60/70: now 50/70

• 40/50: now 30/50

• 20/30:

• Origin: Petroleum Crude

• Class: Paraffinic base Crude

Example: UK Naphthenic based bitumen



INTRODUCTION


43ºC to 63ºC

Binder Softening Point Application Carriage

70/100 Cool AC, SD, Maint Urban Roads

50/70 Temperate AC, DBM Highways

30/50 Warm DBM Highways


INTRODUCTION


Average maximum temperatures recorded for the last 3 years compared to the long-

term mean.

Degree Celsius

STATION LTM 2015 2016 2017 SUB SURF

Lodwar 35.9 36.2 36 35.9 45.9

Nairobi (Wilson) 25 25.7 25.2 25.9 35

Nyahururu 21.7 22.8 22.4 23.1 31.7

Kisumu 29.7 30.1 30.2 29.2 39.7

Voi 30.9 31.3 31.5 31.5 40.9

Machakos 25.2 26.2 25.4 25.8 35.2

Kericho 23.6 24.9 25 24.9 33.6

Mombasa 30.3 30.8 31 31 40.3

Wajir 34.1 35.5 35.2 35 44.1

Maximum (daytime) temperatures exhibited a higher variation from the long-term mean

SP above 40ºC will have

tendency to rutting

With black top and UV

absorption Sub surface

temp will rise drastically

SP range from

20/30 to 100/120

pen grade

bitumen


INTRODUCTION

Binder Limitations Evidence

70/100 Softening Point Rutting

50/70 Ageing, Deformation Highways rutting, early fatigue cracking,

30/50 DBM Limited effort used to address deformation

Challenges

Derivatives from pen grade Bitumen

Bitumen Emulsions: Commonly mfg. with 70/100

Uses: tack coats, seals, cold mixes, ETB etc

Cutback Binders: Commonly with 70/100 rarely 50/70

Uses: Primers, Precoats, Seals


Polymer Modification of Bitumen

Chemistry of Bitumen

Bitumen a highly Hydrogenated compound showing highly

complex constitution due to many molecules intertwined in

the system.



Chemistry of Bitumen

Main properties of Road Construction Bitumen

Adhesion: Bonding of Binder to aggregate

Cohesion: Intrinsic inter-molecular strength

Viscoelasticity: Creep and stress relaxation behavior

Thermoplastic: Pliable and moldable at specific temp. solid at low temp.



SARA Fractions

To understand properties and behavior of bitumen:

Rheology

Composition is based on % of SARA fractions



SARA Fractions

Bitumen SARA Characteristics is Affected by

Crude origin

Manufacturing

Grade



SARA Fractions

Bitumen Separation

Asphaltenes: very Polar solids,

solidness of bitumen

Maltenes (Resin, aromatics,

saturates)

Maltenes Separation

Resins: Polar s/Solid –

adhesive nature

Aromatics: non-polar liquid,

dispersion of asphaltene

Saturates: non-polar oils,

pen grade



Ageing of Bitumen

Factor on Bitumen Ageing

Exposure to air: at premix plant (~1% drop in pen), in-service life

Exposure to UV: at in-service life

Exposure to Heat: Premix plant and in-service life

Exposure to water: in-service wet regions or damaged pavement

IMPACT


Kenya Experience with PMB

Polymers



Polymers used in Kenya

Modifiers Already Used

1. PR-Industrie: PR-Plast-S

2. Dynasol: Calprene C411 is SBS 70/30 = Butadiene/styrene

3. BASF: Butonal NS198 (Cationic SBR Latex)

4. Synthomer: Revertex Natural Rubber 65%



Polymers used in Kenya

POLYMER PRODUCT PROJECT KM YEAR

Calprene 411 Colflex-S Southern Bypass 30km 2013

Calprene 411 Colflex-A JKIA Runway rehabilitation 4km 2015

Calprene 411 Colflex-2 Oloitoktok-Emali junct (SGR) 4km 2015

PR-Plast S PR-Plast-S Mai-Mahiu (trial) 50mm 1km 2010

PR-Plast-S PR-Plast-S Eldoret Bypass Phase 1 32km 2016

NS 198 SLX-80 Bungoma (SD) 1.5km 2015

Surface Dressing

Colflex-S (Modified 80/100) Single Seal

SLX-80 (emulsion based on K170) Double Surface dressing

Asphalt Concrete

Colflex-A (High Modified Binder >4% for JKIA)

PRPlast-S (Admix anti rutting additive)



Polymers proposed to be used

POLYMER PRODUCT PROJECT KM YEAR

Calprene 411 Colflex-S Moi Aiport Mombasa 4km 2018

Calprene 411 Colflex-A Mombasa-Nbo Hwy 2018

Olefins Superplast Garsen Lamu 10km 2018

Challenge

SBS production and Hauliage to Mombasa – challenge

Onsite production and cost implication (possible and viable)

PG specifications (guidelines required for Kenya)



CALPRENE 411

Surface Dressing

Colflex-S (Modified 80/100) Single Seal

Class S-E1

Southern Bypass

Polymer 3% plus crosslinking

Technical Guideline: The use of modified bituminous binder in road construction TG 1 Third Edition July 2015 page



CALPRENE 411


Formulation with SBS

Critical threshold 4%

Storage Stability



BUTONAL NS 198

Surface Dressing (With SLX-80 Emulsion)

Colas SLX80 (Emulsified 80/100 to equivalent K1-70 per BS-434)

Class SC-E1

Bungoma

SBR Polymer 3%

Technical Guideline: The use of modified bituminous binder in road construction TG 1 Third Edition July 2015



CALPRENE 411

Asphalt Concrete

Colflex-A (Modified 60/70) 50mm AC

Class A-E2 (Asphalt Elastomeric Grade)

JKIA Runway Polymer >4%




PR Plast-S


Asphalt Concrete

Add mix to premix plant

Pellets 6mm


Application Case Study Examples

JKIA – Runway Rehabilitation June 2015

MillingPaving AE-2 (high Mod Asphalt)

RollingPaving

SBS Highly Modified Bitumen SP >80



JKIA – Runway Rehabilitation June 2015

Situations (Pros and Cons)Formulation was unique >4% SBS. Therefore storage stability

required stringency

Site Storage Specs: thermometers, mixers, pumps must function

at all times

Blending of AC and laying had tight window

Airport closes at 11pm,

Team mobilize on site (Mill, Tack Coat, Pave, Compact, Mark)

Demobilize by strict 5am

Airport Open for flight at 6am

The pavement cannot have faults at this requirements.

Great plus pavement was ready for dynamic load by 6am.



Mai Mahiu – Section Trial 2010

PR Plast S

Batched Meltable Bags

Laying at Mai Mahiu Road

Compaction as normalAfter 2 year of in service – No Rutts

Premix Plant only



Mai Mahiu – Section Trial 2010

ChallengesMinimal Challenge

Require a hopper for loading polymer

Advantage

Storage stability not required

Easy Batch in meltable bags

Modified AC is ready in <20 Min vis a vis SBS blending more than

6 hours with lab pre-blending trials.

Allows anti-rutting pavements to be realized in remote areas

Example: Garsen – Lamu 130km proposal for same Admix



Southern Bypass 2015

Receiving Binder Colas plant Nairobi Conventional sprayer can also do the job

but with a well trained Spray driver




Chipping

Completed Course

Completed Course




ChallengesScheduling dynamics client and plant (producing for JKIA and CRBC)

As the first project to use PMB in totality – Understanding binder.

ADVANTAGE

Facilities available in Nairobi

Sprayers available.

Competency at Production plant (QC)

Competency at site

Price variance <2% of project cost



Bungoma County road

Trial SLX 80 Section Trial 80/100Junction to Main road



Bungoma County road (LVSR)

ChallengesA trial material (unique formulation production – high viscosity

K170+R) – especially with paraffinic bitumen

Aggregate 14/20 + 06/10 (double seal)

Chip spreader breakdown

Learning right temperature prep the binder

Precoating of chippings with MC30 (alt. provided emulsion primer)

ADVANTAGE

Ready to apply in wet condition

Traffic surface in 12 hours

No site heating therefore heating cost and safety to workers.

Safe for workers

Flexible work schedule

Durable pavement (built with PME)


COST

PR PLAST COST

1KM x 7m x 50mm = 350M3

Wt of AC (2.35) = 822.5Mt

Cost of AC/MT = 9,500/-

Cost of AC/KM = 7,813,750/=

Polymer 0.4% = 3.3MT/km

Polymer cost ksh 238,419/Mt or 786,782.70/Km

% of Polymer cost to AC cost = 10%

@60Mn/km cost of road = 1.31% of cost


COST

Polymer Ksh/Mt %/Mt of

AC 50mm

Qty/km

(822.5Mt)

Cost of

PMB/km

Cost of

PMA/km

PR Plast 238,419 0.4% 3.29mt 784,398.51 8,598,148

SBS 140,000 5.5% 45.23mt 6,332,200 9,939,560

Course Ksh/Mt %/Mt of

AC

Qty/km

(822.5Mt)

Cost of

bit/km

Cost of

HMA/km

AC 9500 5.5% 45.24mt 3,528,252 7,813,750

DBM 9500 4.5% 37.0mt 2,886,000 7,813,750

Assumption: Project cost 60Mn/Km

PR-plast: 1% increment

SBS: 3.54% increment


CONCLUSION

Adopt PM Binder Use in Kenya

PMB is a viable technology for Pavement construction

It enhances:

1. Ageing

2. Thermal resistance

3. Rutting

4. Raveling and Shoving

5. Apart form production/manufacture of PMB other laying techniques

don’t change considerably

6. Safety is a must due to enhanced binder properties

Considering cost increase in the project, advantages out weigh the cost

factor <3.5%. Therefore evaluating candidate roads should be considered

for application where appropriate need is found.


Recommendations

Adopt PM Binder Use in Kenya

Research and development to include Specs and guide in RDM

Capacity development to Construction industry to appreciate PMB as the

technology critical to pavement durability

Pavement Design Engineers

Specifiers – Material Engineer

Suppliers – Import to fit Kenya specs

Manufacturers – Produce locally compliant materials

Applicators – train on use, and right handling of product

MTRD – custodian of specifications to guide in its appropriation.

Determination of National temp mapping in aid to develop PG graded

binders befitting Kenya



THANK YOU

Q & A

Web: www.aiea.co.ke

Documents

Experience of polymer modified bitumen and emulsion … of... · • To demystify Bitumen, asphalt and related technologies. ... 70/100 Softening Point Rutting 50/70 Ageing, Deformation