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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
International Transport and Road Research Conference (iTRARR 2018)
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
International Transport and Road Research Conference (iTRARR 2018)
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
Bitumen Roads in Kenya - History
International Transport and Road Research Conference (iTRARR 2018)
INTRODUCTION
Bitumen Roads in Kenya - History
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
International Transport and Road Research Conference (iTRARR 2018)
INTRODUCTION
Bitumen Roads in Kenya - History
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
International Transport and Road Research Conference (iTRARR 2018)
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
International Transport and Road Research Conference (iTRARR 2018)
Polymer Modification of Bitumen
Chemistry of Bitumen
Bitumen a highly Hydrogenated compound showing highly
complex constitution due to many molecules intertwined in
the system.
International Transport and Road Research Conference (iTRARR 2018)
Polymer Modification of Bitumen
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.
International Transport and Road Research Conference (iTRARR 2018)
Polymer Modification of Bitumen
SARA Fractions
To understand properties and behavior of bitumen:
Rheology
Composition is based on % of SARA fractions
International Transport and Road Research Conference (iTRARR 2018)
Polymer Modification of Bitumen
SARA Fractions
Bitumen SARA Characteristics is Affected by
Crude origin
Manufacturing
Grade
International Transport and Road Research Conference (iTRARR 2018)
Polymer Modification of Bitumen
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
International Transport and Road Research Conference (iTRARR 2018)
Polymer Modification of Bitumen
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
International Transport and Road Research Conference (iTRARR 2018)
Kenya Experience with PMB
Polymers
International Transport and Road Research Conference (iTRARR 2018)
Kenya Experience with PMB
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%
International Transport and Road Research Conference (iTRARR 2018)
Kenya Experience with PMB
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)
International Transport and Road Research Conference (iTRARR 2018)
Kenya Experience with PMB
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)
International Transport and Road Research Conference (iTRARR 2018)
Kenya Experience with PMB
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
International Transport and Road Research Conference (iTRARR 2018)
Kenya Experience with PMB
CALPRENE 411
Technical Guideline: The use of modified bituminous binder in road construction TG 1 Third Edition July 2015 page
Formulation with SBS
Critical threshold 4%
Storage Stability
International Transport and Road Research Conference (iTRARR 2018)
Kenya Experience with PMB
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
International Transport and Road Research Conference (iTRARR 2018)
Kenya Experience with PMB
CALPRENE 411
Asphalt Concrete
Colflex-A (Modified 60/70) 50mm AC
Class A-E2 (Asphalt Elastomeric Grade)
JKIA Runway Polymer >4%
Technical Guideline: The use of modified bituminous binder in road construction TG 1 Third Edition July 2015 page
International Transport and Road Research Conference (iTRARR 2018)
Kenya Experience with PMB
PR Plast-S
Technical Guideline: The use of modified bituminous binder in road construction TG 1 Third Edition July 2015 page
Asphalt Concrete
Add mix to premix plant
Pellets 6mm
International Transport and Road Research Conference (iTRARR 2018)
Application Case Study Examples
JKIA – Runway Rehabilitation June 2015
MillingPaving AE-2 (high Mod Asphalt)
RollingPaving
SBS Highly Modified Bitumen SP >80
International Transport and Road Research Conference (iTRARR 2018)
Application Case Study Examples
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.
International Transport and Road Research Conference (iTRARR 2018)
Application Case Study Examples
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
International Transport and Road Research Conference (iTRARR 2018)
Polymer Modification of Bitumen
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
International Transport and Road Research Conference (iTRARR 2018)
Application Case Study Examples
Southern Bypass 2015
Receiving Binder Colas plant Nairobi Conventional sprayer can also do the job
but with a well trained Spray driver
International Transport and Road Research Conference (iTRARR 2018)
Application Case Study Examples
Southern Bypass 2015
Chipping
Completed Course
Completed Course
International Transport and Road Research Conference (iTRARR 2018)
Application Case Study Examples
Southern Bypass 2015
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
International Transport and Road Research Conference (iTRARR 2018)
Application Case Study Examples
Bungoma County road
Trial SLX 80 Section Trial 80/100Junction to Main road
International Transport and Road Research Conference (iTRARR 2018)
Application Case Study Examples
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)
International Transport and Road Research Conference (iTRARR 2018)
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
International Transport and Road Research Conference (iTRARR 2018)
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
International Transport and Road Research Conference (iTRARR 2018)
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.
International Transport and Road Research Conference (iTRARR 2018)
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
International Transport and Road Research Conference (iTRARR 2018)
Application Case Study Examples
THANK YOU
Q & A
Web: www.aiea.co.ke