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INTELLIGENT COMPACTION:AN OVERVIEW

ByJean-Louis Briaud, PhD, P.E.

Professor and Holder of the Buchanan ChairDepartment of Civil Engineering

Texas A&M University

J-L Briaud, Texas A&M University

ACKNOWLEDGEMENTS

Chris Dumas, FHWA Hans Kloubert, BOMAG Roland Anderegg, AMMANN

J-L Briaud, Texas A&M University

1 MPa = 150 psi10 kN = 1 ton

25 mm = 1 inch

J-L Briaud, Texas A&M University

INTELLIGENT COMPACTION:AN OVERVIEW

Current practiceFuture practiceModulus and dry densityCompactions methodsIntelligent Compaction

PrincipleEquipment and instrumentationHow to get the stiffnessHow to get the modulusSpecs

Future needs

J-L Briaud, Texas A&M University

CURRENT PRACTICEBased on Density

• LAB: Proctor test to get dry densityvs. water content curve

• SPEC: x% of γd max within range of w opt

• FIELD: Compact and check that γd andw meet the specs

J-L Briaud, Texas A&M University

• LAB : Proctor Test

J-L Briaud, Texas A&M University

CURRENT PRACTICEBased on Density

Water Content (%)

3 9 15 21

14

16

18

20

Dry

Density (

kN

/m3

)

!d max

w opt

S = 1S = 0.9

Water Content (%)

3 9 15 21

14

16

18

20

Dry

Density (

kN

/m3

)

!d max

w opt

S = 1S = 0.9

• SPECIFICATIONS.X % of γd max within range of w opt

• FIELD

J-L Briaud, Texas A&M University

Nuclear Density MeterFor γd and w

CURRENT PRACTICEBased on Density

Dry Density:Advantages and Disadvantages

1. AdvantagesAccumulated knowledgeWell defined parameterIndication of solids per unit volume

2. DisadvantagesNot related to designNot very sensitiveNot easy to measure quickly in field

J-L Briaud, Texas A&M University

FUTURE PRACTICEBased on Modulus

• LAB: Modulus test to get modulus vs. water content curve

• SPEC: x% of E max

within range of w opt

• FIELD: Intelligent compaction and checkthat E max and w meet the specs

J-L Briaud, Texas A&M University

• SPECIFICATIONSX % of E max within range of w opt

• FIELD

J-L Briaud, Texas A&M University

Modulus MeterFor E and w

Intelligent Compaction

EIC

FUTURE PRACTICEBased on Modulus

FUTURE PRACTICEBased on Modulus

• LAB : Modulus Test

J-L Briaud, Texas A&M University

Water Content (%)6 10 14 18

Mod

ulus

(MPa

)

0

20

40

Sand

Clay

Emax

wopt

Modulus:Advantages and Disadvantages

1. AdvantagesDirectly related to designVery sensitive to water contentEasy to measure quickly in field

2. DisadvantagesMany influencing factorsNo lab test to get E vs. wNo target valuesNew concept

J-L Briaud, Texas A&M University

Which Modulus?

DEFINITIONInitialSecantTangentUnload-ResilientCyclicReload

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Which Modulus?

J-L Briaud, Texas A&M University

Which Modulus?

STATE FACTORSDensityStructureWater contentStress historyCementation

J-L Briaud, Texas A&M University

Which Modulus?

LOADING FACTORSStress levelStrain levelStrain rateNumber of cyclesDrainage

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Which Modulus?PLATE MODULUS in FIELD

J-L Briaud, Texas A&M University

BPT: Briaud Plate Test

Which Modulus?PLATE MODULUS in LAB

J-L Briaud, Texas A&M University

(E.CVEN#1)(08/02/2003)

0

50

100

150

200

250

0.00 0.02 0.04 0.06 0.08 0.10 0.12Displacement(mm)

Load

( N

)

EL=12.91 MPa

Er= 19.62 MPa

BPT: Briaud Plate Test

Range of Modulus

Steel: 200,000 MPaConcrete: 20,000 MPaWood, Plastic: 13,000 MPaRock: 2,000 to 30,000 MPaAsphalt: 150 to 25000 MPaSoil: 5 MPa to 1000 MPaMayonnaise: 0.5 MPa

J-L Briaud, Texas A&M University

NGES Silty Sand (Mold #5)

0

10

20

30

40

0 2 4 6 8 10 12 14

Water Content (%)

Mo

du

lus (

MP

a)

0

4

8

12

16

20

Dry

Un

it W

eig

ht

(kN

/m3)

Plate Reload Modulus (MPa)

Dry Unit Weight (kN/m^3)

J-L Briaud, Texas A&M University

Modulus measured with BPT: Briaud Plate Test

NGES Silty Sand (Mold #6)

0

10

20

30

40

0 2 4 6 8 10 12

Water Content (%)

Mo

du

lus

(M

Pa

)

0

4

8

12

16

20

Dry

Un

it W

eig

ht

(kN

/m3)

Plate Reload Modulus (MPa)

Dry Unit Weight (kN/m^3)

J-L Briaud, Texas A&M University

Modulus measured with BPT: Briaud Plate Test

NGES Sand + Porcelain Clay (Mold #5)

0

10

20

30

40

0 2 4 6 8 10 12 14 16Water Content (%)

Mo

du

lus (

MP

a)

0

4

8

12

16

20

Dry

Un

it W

eig

ht

(kN

/m3)

Plate Reload Modulus (MPa)

Dry Unit Weight (kN/m^3))

J-L Briaud, Texas A&M University

Modulus measured with BPT: Briaud Plate Test

NGES Sand + Porcelain Clay

J-L Briaud, Texas A&M University

Modulus measured with BPT: Briaud Plate Test

0

20

40

60

0 2 4 6 8 10 12 14 16Water Content (%)

Mo

du

lus (

Mp

a)

0

4

8

12

16

20

Dry U

nit

Weig

ht

(kN

/m3)

Plate Reload Modulus (MPa)

Dry Unit Weight (kN/m^3)

0

20

40

60

0 2 4 6 8 10 12 14 16Water Content (%)

Mo

du

lus (

Mp

a)

0

4

8

12

16

20

Dry U

nit

Weig

ht

(kN

/m3)

Plate Reload Modulus (MPa)

Dry Unit Weight (kN/m^3)

• Only one of those threeis not enough

• Two of those three aresufficient

• All three would be nice

J-L Briaud, Texas A&M University

1. Density?2. Modulus?3. Water Content?

Three CompactionControl Methods

• Conventional Compaction• Continuous Control

Compaction• Intelligent Compaction

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Conventional Compaction(static or vibratory smooth drum

or sheep-foot)

J-L Briaud, Texas A&M University

Continuous VibratoryCompaction Control

• Instrumented vibrating rollers• Measure roller accel. as a function of time• Calculate a soil stiffness or modulus• Modulus is compared to target value (specs)• The modulus value tells the operator if thespecified compaction level is reached

J-L Briaud, Texas A&M University

Intelligent Vibratory Compaction

• Instrumented vibrating rollers• Measure roller accel. as a function of time• Calculate a soil modulus• Intelligent roller modifies automaticallyand instantaneously settings (force, ampl.,freq.) to meet the target modulus

J-L Briaud, Texas A&M University

Slide 29

Recompaction of soft formation area with VARIOCONTROLautomatic mode, presetting ( target value ) EVIB = 80 MN/m²

Slide 30

Intelligent Compaction

Intelligent CompactionTests in the U.S.A.

4 2 -2

200

Soil Reaction Force (kN)

Fx max

-4

Fstat

x

Fx

1st Pass2nd Pass

3rd Pass

Drum Oscillation (mm)

Force-Displacement Curves

J-L Briaud, Texas A&M University

From BOMAG

From Acceleration to Stiffness

2 cos( ) ( )B d d u u f dF m x m r t m m g! " + # # + +&&

B B d B dF k x d x! + &

FB: soil-drum-interaction-force md: mass of the drum (kg)xd: vert. disp. of drum (m) : acceleration of drummf: mass of the frame (kg) mu: unbalanced mass (kg)ru: radial distance for mu Ω = g: acc. due to gravity (m/sec2) f: frequency of rotating shaft (Hz)

: velocity of drum kB: stiffness of soildB: damping coefficient (dB ~ 0.2)

dx&&

dx&&

2 f!

dx&

xw

FFlieh= mew2 cos(ö)

mR?g

mR?g

FB

xw

FFlieh= mew2 cos(ö)

mR?g

mR?g

FB

FFlieh= mew2 cos(ö)

mR?g

mR?g

FB

mw? g

J-L Briaud, Texas A&M University

Stiffness or Modulus?

K = F/x in MN/mE ~ σ/ε in MN/m2 or MPa

E = α F/BxK = F/x = EB/α

J-L Briaud, Texas A&M University

Stiffness or Modulus?

Stiffness depends on the size of theroller.

Modulus does not; it is a property ofthe soil only.

Use the modulus, not the stiffness

J-L Briaud, Texas A&M University

From Stiffness to Modulus(theoretical)

dx&&

( )( ) ( )

[ ]3

2

2

MN m

12 1 2.14 ln

2 1 16

B

f d

E Lk

L E

m m R g

!

!"

"

# #=

$ %& '# #( )# * # + # + ,( )* # # + # #+ ,- ./ 0

J-L Briaud, Texas A&M University

From Stiffness to Modulus(experimental)

J-L Briaud, Texas A&M University

From AMMANN

Soil Modulus for Intelligent Compaction

Soil: 5 MPa unacceptable200 MPa excellent

J-L Briaud, Texas A&M University

Soil layers Density Bearing capacity Eveness(Standard Proctor) (load bearing test, EV2) (4 m straight edge)

Laying and compaction specification for

road construction in Germany

Subbase 100 - 103 % * 100 - 150 MN/m?* 20 mm

Capping layer 100 - 103 % * 100 - 120 MN/m?* 40 mm

Formation 97 - 100 % * 45 - 80 MN/m?* 60 mm

* depending on road classification and road design

Specifications based on Modulus

J-L Briaud, Texas A&M University

From BOMAG

1. Reference modulus = plate test?

2. Develop simple lab modulus test

3. Study modulus vs water/asph. Content

4. Demonstrate that IC is better than CC

5. Calibrate rollers against plate modulus

6. Use same modulus test (lab and field)

FUTURE NEEDS

J-L Briaud, Texas A&M University

Example of same modulus testin lab and in field

J-L Briaud, Texas A&M University

BCD Test: Briaud Compaction Device

BCD on Proctor Mold BCD in the Field

7. Develop specs based on modulusfordiff. pavement cond.

8. Can the asphalt modulus be isolatedfrom the soil modulus

9. Use modulus control equipment

10. Demonstrate the IC equipment

11. First International Conference on Compaction

FUTURE NEEDS

J-L Briaud, Texas A&M University

INTELLIGENT COMPACTION: OVERVIEW AND RESEARCH NEEDS

Jean-Louis Briaud (briaud@tamu.edu) and Jeongbok Seo

From BOMAG

From GEODYNAMIK

kB . . . . . . . . . . . . . . . . . . . . . . . . . . 70 M N/ mkB m ax. . . . . . . . . . . . . . . . . . 150 M N/ mkB m i n. . . . . . . . . . . . . . . . . . . 30 M N/ mΔ kB . . . . . . . . . . . . . . . . . . . . . . +10 M N/ mv. . . . . . . . . . . . . . . . . . . . . . . . . . . 3. 2 km / hL. . . . . . . . . . . . . . . . . . . . . . . . . . . 90 m

0 40 80 120 160k B

M N/ m0 m

25 m

50 m

75 m

Printer: - Single Device- Recording- Increase of Compaction

DATAS

ADSkB . . . . . . . . . . . . . . . . . . . . . . . . . . 70 M N/ mkB m ax. . . . . . . . . . . . . . . . . . 150 M N/ mkB m i n. . . . . . . . . . . . . . . . . . . 30 M N/ mΔ kB . . . . . . . . . . . . . . . . . . . . . . +10 M N/ mv. . . . . . . . . . . . . . . . . . . . . . . . . . . 3. 2 km / hL. . . . . . . . . . . . . . . . . . . . . . . . . . . 90 m

0 40 80 120 160k B

M N/ m0 m

25 m

50 m

75 m

kB . . . . . . . . . . . . . . . . . . . . . . . . . . 70 M N/ mkB m ax. . . . . . . . . . . . . . . . . . 150 M N/ mkB m i n. . . . . . . . . . . . . . . . . . . 30 M N/ mΔ kB . . . . . . . . . . . . . . . . . . . . . . +10 M N/ mv. . . . . . . . . . . . . . . . . . . . . . . . . . . 3. 2 km / hL. . . . . . . . . . . . . . . . . . . . . . . . . . . 90 m

0 40 80 120 160k B

M N/ m0 m

25 m

50 m

75 m

Printer: - Single Device- Recording- Increase of Compaction

DATAS

ADSADS

From AMMANN

December, 2003 Texas A&M University

THANK YOU

briaud@tamu.edu

J-L Briaud, Texas A&M University