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Performance Evaluation of Lime Stabilized Performance Evaluation of Lime Stabilized Materials on...
Transcript of Performance Evaluation of Lime Stabilized Performance Evaluation of Lime Stabilized Materials on...
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Performance Evaluation of Lime Stabilized Performance Evaluation of Lime Stabilized Materials on Field Test SitesMaterials on Field Test Sites
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Tania Ávila-EsquivelGustavo A. Badilla-Vargas
June 2013
INTRODUCTION
COSTA RICA, Central America
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INTRODUCTION
Some facts about COSTA RICA…
52 000 k 2 (T i 700 000 k 2 M i i 2 000 000 k 2)• 52,000 km2 (Texas is 700,000 km2, Mexico is 2,000,000 km2)• 4,509,290 inhabitants• No army since 1948• 2,5 millions of tourists in 2010• Language: Spanish• Currency: El Colón• Capital: San José• Two seasons: Rainy and Dry• 20 volcanos aprox. 5 active during last century
INTRODUCTIONElevations
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INTRODUCTION
• Due to the geological characteristics of Costa Rica, subgrade soils around the country often have high plasticity indexeshigh plasticity indexes.
These soils are
used as foundation for
pavement structures or
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unpaved roads.
Considerations for the selection of lime as a suitable means of soil stabilization:
• Gradation
INTRODUCTION
• Plasticity or soil texture
As a general rule lime reacts with soils of
medium to high plasticity.
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FIELD TEST SITEST1 Characteristics:
• Location: Barrio La Unión, Cañas, Guanacaste (Latitude N10°25.873’ Longitude W85°05.929’)
• Dry climatic region windy flat alignmentDry climatic region, windy, flat alignment• Soil type: SM (USCS) or A‐4 (AASHTO)• 6% Lime, after pH test• Low plasticity, lime added for dust control• 20cm thickness, 100m length
T2 Characteristics:• Location: Calle El Alto, Sector Copalchí, Distrito Quebradilla, Cartago
(Latitude N9°49.739’ Longitude W84°01.729’)• Humid climatic region, forest area, flat alignment• Soil type: ML (USCS) or A‐6(5) (AASHTO)• 6% Lime, after pH test• High plasticity, lime added to decrease deformation and improve
resistance• 20cm thickness, 100m length
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Number of Rain Days per Year
CLIMATE CONDITION OF THE SITES
T1
T2
Number of Dry Months per Year
CLIMATE CONDITION OF THE SITES
T1
T2
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VISUAL ASSESMENT
Before After
MONITORING - 1 MONTH
Dry SeasonPresence of
surface crackssurface cracks
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MONITORING - 2 MONTHSDry SeasonPresence of
surface crackssurface cracks
MONITORING - 4 MONTHS
Rainy SeasonSurface damage
due to rainfall
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MONITORING - 7 MONTHS
Rainy SeasonSurface damage
due to rainfalldue to rainfall
MONITORING - 1 YEAR
Dry SeasonDry Season
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PERFORMANCE (LWD RESULTS), Example
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Elastic Modulus (0+040 m)Load II (7kN)
Load I (5kN)
Initial Condition
20
30
40
50
60
Modulus (M
Pa)
Dry Season
Rainy Season
0
10
Jan 10, 12 Jan 12, 12 March, 12 May 29, 12 May 30, 12 Aug, 12 Nov, 12 Jan, 13
PERFORMANCE (DCP RESULTS)
0 0
0 50 100 150
CBR (%)
CBR vs. Penetration (0+060 m)
0,0
200,0
400,0
600,0
800,0
enetration(m
m)
Jan 10, 2012
Jan 12, 2012
March 2012
May 2012
Sept 2012
1000,0
1200,0
1400,0
Pe
Jan 2013
JPAM5
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CARTAGO FIELD TEST SITECARTAGO FIELD TEST SITE
(T2)(T2)
Effects produced byaccumulation of waterdue to lack adequate
FIELD CONDITION BY THE END OF 2011
qsurface drainage system
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VISUAL ASSESMENT
Before After
MONITORING - 1 MONTH
Dry Season
Section of the roadnot stabilized
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MONITORING - 2 MONTHS
Dry SeasonPresence of
surface crackssurface cracks
MONITORING - 4 MONTHSRainy SeasonEffects produced byaccumulation of waterdue to lack adequatedue to lack adequatesurface drainage system
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Section of the roadnot stabilized
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MONITORING - 7 MONTHS
Eff t d d
Section of theroad notstabilized
Effects producedby accumulationof water due tolack adequatesurface drainagesystem
MONITORING - 1 YEAR
Dry Season
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Section of the roadnot stabilized
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PERFORMANCE (LWD RESULTS), Example
Initial Condition60
70
Elastic Modulus (0+020 m) Load II (7kN)
Load I (5kN)
Dry Season
Rainy Season
30
40
50
60
Modulus (M
Pa)
0
10
20
Feb 14, 12 Feb 15, 12 March, 12 Apr, 12 June, 12 Sept, 12 Nov, 12 March, 13
M
PERFORMANCE (DCP RESULTS), Example
0
0 20 40 60 80 100 120
CBR (%)
CBR vrs penetration (0+060 m)
0
200
400
600
800Penetration (mm) Feb 14, 2012
Feb 15, 2012
March 2012
April 2012
Sept 2012
1000
1200
1400
Sept 2012
Nov 2012
Feb 2013
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ADVANTAGES OF APPLYING LIME
Technical Advantages:
• Allows the use of natural soil, improving the mechanical propertiesproperties.
• Ensures the stability of the road surface, due to its reduction in permeability
• Reduces volume changes due to swelling or shrinkage,
• Higher resistance to erosion.
• Maintain subgrade elevation, especially if there are l k l d i lcomplementary works already in place.
• Allows immediate opening to traffic.
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Economic and environmental benefits:
ADVANTAGES OF APPLYING LIME
• Increased use of local materials, sometimes with inadequate characteristics. Minimize the need of long hauling distances.
• Improved efficiency in construction process when high performance equipment is used.
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FINAL COMMENTS
• Compaction process is crucial in ensuring the benefits of lime stabilization.
• Improvements have been indentified on lime stabilized• Improvements have been indentified on lime stabilized materials.
– However, longer monitoring will be conducted to measuremid‐ and long‐ term performance.
• Observed material response variations can be associated to Seasonal Variation (dry‐rainy season).
THANK YOU FOR THE ATTENTION!
t i il i [email protected]@[email protected]