ALTERNATIVE SURFACINGS FOR LOW VOLUME ROADS IN … · 294.1 Billion USD 0 500 1000 1500 2000 2500...
Transcript of ALTERNATIVE SURFACINGS FOR LOW VOLUME ROADS IN … · 294.1 Billion USD 0 500 1000 1500 2000 2500...
Dr. Anton HartmanAurecon, Pretoria, South Africa
Ass. Min. James ReynoldsMPW, Monrovia, Liberia
ALTERNATIVE SURFACINGS FOR LOW VOLUME ROADS IN GHANA, SIERRA LEONE AND LIBERIA
CONTENT• Background• Approach
Design lead thinking Design criteria Surfacing types
• Liberia experience• Outcome and key findings
https://www.6sqft.com/believe‐it‐or‐not‐the‐worlds‐entire‐population‐can‐fit‐inside‐new‐york‐city/
AIMTo find surfacing solutions that may be viable for low volume roads compared to traditional gravel surfacing.
Liberia
Ghana
SierraLeone
$GDP
Ghana
Liberia
Sierra Leone
42.69 Billion USD
3.67 Billion USD
2.10 Billion USD
South Africa 294.1 Billion USD
0 500 1000 1500 2000 2500 3000 3500
Sierra Leone
Ghana
Liberia
South Africa
Total Rainfall (mm)
Pretoria (660 mm)Monrovia (3160 mm)
Accra (994 mm)Freetown (2866 mm)
0
50
100
150
200
250
SierraLeone
Ghana Liberia SouthAfrica
Feed
er R
oad L
ength
('000
km)
4,152
km 24,10
0 km
5,702
km
222,9
00 km
Only Ghana has surfaced
Feeder Roads
Land Area
Liberia (99,067 km2)
Sierra Leone(71,740 km2)
Ghana(238,553 km2) South Africa
(1,210,090 km2)
Population
25.5 Million
Liberia
Ghana
Sierra Leone 6.1 Million
4.6 Million
South Africa 57.4 Million
COUNTRY COMPARISON
EXPLORING THE WHY OF THINGS…
WHAT IS?
WHAT IF?
WHAT WOWS?
WHAT WORKS?
FROMABSTRACT TO
NEW VALUEBUILD
UNDERSTANDING
SHAPE
HYPOTHESES
MAKE BETTER
DECISIONS
Understanding what is happening
and setting a design criteria
Test the ideas generated from the
design criteria
Providing the final alternative surfacing
options
Understand what’s going on today
Explore, experiment on what might be possible
for tomorrow
Test assumptions. Refine ideas. Test again.
Identify best solution.
Improve the solution and deliver.
Create new, more meaningful
value.
EXPLORING THE WHY OF THINGS…
WHAT IS?
WHAT IF?
WHAT WOWS?
WHAT WORKS?
FIRST WORKSHOP
SECOND WORKSHOP
THIRD WORKSHOP
Understand what’s going on today
Explore, experiment on what might be possible
for tomorrow.
Test assumptions. Refine ideas. Test again.
Identify best solution.
Improve the solution and deliver.
Create new, more meaningful
value.
INTERNAL WORKSHOP
CHALLENGES
High Rainfall
High Temperatures
Flooding of low lying areas
Steep Slopes
Skilled Labour
Resources
CHALLENGES
DESIGN CRITERIA• Require low maintenance• Resistant to environment• Labour intensive construction• Skill transfer to different industries• Locally available material• Low level of supervision required• Uncomplicated design• Low skilled contractor can construct
Surfa
cing
Optio
ns Bituminous Surfacing
Seals
Sand
Slurry
Single
Cape
Otta
Double
Inverted Double
Triple
ChokedAsphalt
Cold mix
Hot mixConcrete Surfacing
Plain Jointed
Dowel Jointed
Ultra thin
Roller Compacted
Continuously Reinforced
Strip Roads
Discrete elements
Concrete
Cobbles
Clay
Geocell
UNCONVENTIONAL ALTERNATIVES
BITUMEN/CEMENT MODIFICATION
RAW LATEX
BEESWAX
COCOA
SUGARCANE ASH
PALM OIL
TERMITE SALIVA
PLASTIC ROADS
BITUMEN RUBBER
SELF HEALING CONCRETE
INVERTED CONCRETE ROADS
SOLAR PANNELS
IMAGES FROM THE FOLLOWING SOURCES
http://blogs.discovermagazine.com/seriouslyscience/2014/07/22/can-guess-bees-make-hexagons-honeycomb/#.XUvo3GiFOUk
https://en.wikipedia.org/wiki/Natural_rubber#/media/File:Latex_-_Hevea_-_Cameroun.JPG
https://www.treehugger.com/natural-sciences/nature-blows-my-mind-miracles-termite-mounds.html
http://storage.googleapis.com/powop-assets/kew_profiles/Theobroma_cacao_STE_The_cac_20100413AM013_crop_web_fullsize.jpg
https://www.sciencefocus.com/nature/how-long-does-a-bacterium-live/
https://www.chinimandi.com/government-should-consider-scheme-to-purchase-sugarcane-harvesting-machine/
LIBERIAEXPERIENCE
DESIGN CRITERIA
LIBERIA TRIALS
LIBERIA TRIALS
Surfacing Length (m)Concrete strip road 80Hand packed stone 50Otta seal ‐ double crushed rock 100Otta seal ‐ double lateritic gravel 60Otta seal ‐ single crushed rock 670Otta seal ‐ single crushed rock + sand 100Single seal 700Single seal + sand 60
LIBERIA TRIALSCOMMENTSAPPEARANCEDESCRIPTION
OTTA SEAL WITH NATURAL LATERITE GRAVEL
VERY GOOD APPEARANCE. DIFFICULT TO SIEVE AND KEEP MOISTURE OUT.
OTTA SEAL WITH CRUSHED AGGREGATE
SOME BLEEDING OBSERVED.
LIBERIA TRIALSDESCRIPTION
HAND PACKED STONE (COBBLES)
VERY ROUGH SURFACE, SOME STONE LOSS/POTHOLES ALREADY PRESENT. DIFFICULT TO SHAPE AND LAY.
DUAL STRIPS
CONSTRUCTED ON STEEPEST ROAD SECTION.SOME EDGE DROPS OBSERVED. MOTORCYCLES TRAVELLING ON SHOULDER. EROSION OF SIDE DRAIN OBSERVED. VERY EASY TO CONSTRUCT.
COMMENTSAPPEARANCE
LIBERIA TRIALSDESCRIPTION
SINGLE SEAL (16mm WITH CAT 72 EMULSION)
ROUGH SURFACE, BLEEDING IN THE WHEELTRACKS.
SINGLE SEAL WITH SAND SEAL
SMOOTH SURFACE, LIGHT BLEEDING WITH SLIGHT DEFORMATION.
COMMENTSAPPEARANCE
OUTCOME AND KEY FINDINGS
DESIGN CRITERIA
0.0
1.0
2.0
3.0
4.0
5.0
Low designskill levelrequired
Skill transferto differentindustries
Low skillcontractor can
construct
Labourintensive
construction
Low level ofsupervision
required
Resilient toenvironment
Require lowmaintenance
Locallyavailablematerials
Weig
hting
Ghana Sierra Leone Liberia Experts
SURFACING SELECTION
0%
5%
10%
15%
20%
25%
30%
35%
Single Seal Double Seal Cape Seal Otta Seal Triple seal ColdAsphalt
ConcreteBlocks
Geo Cells Cobble PlainJointed
Concrete
Doweljointed
concrete
ConcreteStrip Roads
RCC UTRCP
% V
otes
Ghana Sierra Leone Liberia Experts
CONSTRUCTION COST (USD)
0.000.100.200.300.400.500.600.700.80
Sing
le Se
al
Doub
le Se
al
Tripl
e Sea
l
Cape
Sea
l
Otta
Seal
Cold
Asph
alt
Plain
Joint
ed C
oncre
te
Dowe
l Join
ted C
oncre
te
Ultra
-Thin
Con
crete
Rolle
r Com
pacte
d Con
crete
Conc
rete
Strip
Roa
ds
Geo C
ells
Cobb
les
Conc
rete
Bloc
k Pav
ing
Millio
ns
GhanaSierra LeoneLiberia
DISCOUNTED LIFE CYCLE COST
0.000.100.200.300.400.500.600.700.800.90
Sing
le Se
al
Doub
le Se
al
Tripl
e Sea
l
Cape
Sea
l
Otta
Seal
Cold
Asph
alt
Plain
Joint
ed C
oncre
te
Dowe
l Join
ted C
oncre
te
Ultra
-Thin
Con
crete
Rolle
r Com
pacte
d Con
crete
Conc
rete
Strip
Roa
ds
Geo C
ells
Cobb
les
Conc
rete
Bloc
k Pav
ing
Millio
ns
Liberia
With MaintenanceWithout Maintenance
RANKING OF SURFACING OPTIONS
ASPHALT
0.0
0.1
0.3
0.4
0.5
0.6
0.0
0.1
0.0
0.1
0.0
0.1 0.1
0.20.2
0.30.2
0.3
0.4
0.7
0.8
0.9
1
CONSTRUCTION COSTLIFE CYCLE COST
(WITHOUT MAINTENANCE)
LIFE CYCLE COST (WITH MAINTENANCE)
TECHNICAL ANALYSIS (IN COUNTRY)
TECHNICAL ANALYSIS (EXPERTS)
Σ W = 1
RANKING OF SURFACING OPTIONSMonte Carlo Simulation
Σ (Weight x Ranking)
Cold Asphalt
Double Seal
Triple Seal
Cape Seal
Otta Seal
Plain Jointed Concrete
Ultra Thin Concrete
Roller Compacted Concrete
Dowel Jointed Concrete
Concrete Block Paving
Single Seal
Geo Cells
Dual Strips
Determine the number of times
a certain surfacing is
ranked under the top 3
A total of 352 combinations were checked
Prevents bias towards either of
the rankings
TOP 5 SURFACING OPTIONS
TOP 5 SURFACING OPTIONSLIBERIASIERRA LEONEGHANA
12345
OTTA SEAL
PLAIN JOINTED CONCRETE
ULTRA-THIN CONCRETE
CONCRETE BLOCK PAVING
CONCRETE STRIP ROADS
OTTA SEAL
ULTRA-THIN CONCRETE
PLAIN JOINTED CONCRETE
CONCRETE BLOCK PAVING
CONCRETE STRIP ROADS OTTA SEAL
CONCRETE STRIP ROADS
DOUBLE SEAL
CONCRETE BLOCK PAVING
PLAIN JOINTED CONCRETE