INTELLIGENT COMPACTION: AN OVERVIEW By Jean-Louis Briaud, PhD, P.E. Professor and Holder of the Buchanan Chair Department of Civil Engineering Texas A&M University J-L Briaud, Texas A&M University
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
J-L Briaud, Texas A&M University
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
J-L Briaud, Texas A&M University
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
J-L Briaud, Texas A&M University
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 ([email protected]) 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