Performance Evaluation of Lime Stabilized Performance Evaluation of Lime Stabilized Materials on...

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30/04/2013 1 Performance Evaluation of Lime Stabilized Performance Evaluation of Lime Stabilized Materials on Field Test Sites Materials on Field Test Sites 1 Tania Ávila-Esquivel Gustavo A. Badilla-Vargas June 2013 INTRODUCTION COSTA RICA, Central America

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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T1: FIELD TEST SITE

N

T2: FIELD TEST SITE

N

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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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CAÑAS FIELD TEST SITECAÑAS FIELD TEST SITE

(T1)(T1)

FIELD CONDITION BY THE END OF 2011

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INITIAL SUBGRADE CONDITION

INITIAL SOIL SCARIFICATION

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SPREADING OF LIME

MIX AND HOMOGENIZATION PROCESS

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WATER DISTRIBUTION

RECONFORMATION OF THE SUBGRADE

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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

60

70

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

Diapositiva 28

JPAM5 Conversemos sobre este gráfico mañanaJosé Pablo Aguiar Moya, 29/04/2013

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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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INITIAL SUBGRADE CONDITION

INITIAL SOIL SCARIFICATION

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SPREADING OF LIME

MIX AND HOMOGENIZATION PROCESS

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WATER DISTRIBUTION

RECONFORMATION OF THE SUBGRADE

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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

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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]