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Continuous Compaction Control and Other Innovative Field Tests FHWA Intelligent Compaction Strategic Forum December 14-15, 2004 NCAT, Auburn, Alabama John Siekmeier, PE Mn/DOT Office of Materials and Road Research
Outline of Presentation Background In Situ Testing Devices Mn/DOT Case Studies Intelligent Compaction Overview Demonstration at MnROAD Conclusions
Testing for Compaction
Currently (empirical pavement design) Specify
Relative Density (Proctor Test) Specify Moisture Limits (Proctor Test) Test Rolling
Future (mechanistic pavement design) QC:
Intelligent Compaction Equipment QA: Specify Stiffness and Strength QA: Continue to Specify Moisture QA: Automated Test Rolling
Density Testing Issues Proctor Had a Different Idea ASTM Specifies Standard Compactive Effort Optimum Moisture for Compaction Strength and Stiffness May Not Be Achieved Rutting Due to Moisture and Construction Traffic
Proctor Had a Different Idea 1933 “12
inch firm blows” not
12
inch firm strokes
Proctor 1948
“This inadvertent substitution evidently led some organizations to assume that instead of striking a minimum length blow of 12 inches, the tamper should be dropped a distance of 12 inches in free fall.”
Proctor 1948 “Originally published objective of compaction in earth fills was a saturated penetration resistance of 300 lb per sq in.”
“Soil would then have twice the penetration resistance required to permit loaded truck travel when fully saturated.”
“The 12 inch blow was required principally to assure accurate determination of this penetration resistance and was never intended as a ‘standard’ or ‘optimum’.”
Nuclear vs Sandcone Densities Investigation 622, U of M, LRRB, Mn/DOT, 1966 Sandcone results have appreciable errors Greatest errors in high density granular soils More than 5 lbs per cubic foot Due to inherent errors in the sandcone procedure
Nuclear Density vs Sandcone Density Mn/ROAD Aggregate Base 1998, 1999, 2000, 2001, and 2004 145 y = 1.0x - 5.0
N u clear D en sity (lb /ft3)
2
R = 0.7 140
135
130
125 125
130
135
Sandcone Density (lb/ft3)
140
145
Nuclear Compaction vs Sandcone Compaction Mn/ROAD Aggregate Base 1998, 1999, 2000, 2001, and 2004
Nuclear Compaction (percent)
110
105
100
95 95
100
105
Sandcone Compaction (percent)
110
Nuclear Moisture vs Sandcone Moisture Mn/ROAD Aggregate Base 1998, 1999, 2000, 2001, and 2004
N u clear M o istu re (p ercen t)
10
8
6 y = 0.98x + 0.20 2
R = 0.93 4
2 2
4
6
Sandcone Moisture (percent)
8
10
Proctor 1948
The most essential link between theoretical and practical soil mechanics is the collection of better data regarding the compaction equipment and methods required to produce the prescribed shear strengths.
“For in the final analysis, all laboratory and experimental data is just about worthless unless the results secured actually can be applied to the work, a condition that at present is rare.”
New In Situ Tests Are Needed
Achieve agreement between construction quality assurance and seasonal pavement design.
Quantify alternative materials and construction practices. Show economic benefit of improved materials. Reward good construction.
This requires new specifications and new tools. Tools must be quantitative, portable, and accurate in the field.
In Situ Testing Equipment
DCP and Backcalculated FWD Moduli vs Stationing Waseca Co Rd 8, April 7, 2000 Subgrade Below Flyash 100
80
60
40
20
0 1000
2000
3000
4000
Stationing DCP 6 Inch Avg
FWD lowest drop
5000
6000
PRIMA Portable FWD (LWD)
Impulse Device Load
measured Velocity measured Deflection calculated Variable falling mass Variable plate size
Humboldt GeoGauge
State DOTs Using DCP California Colorado Florida Idaho Illinois Iowa Kansas Kentucky Maryland
Massachusetts Michigan Minnesota Mississippi Missouri Montana New Jersey North Carolina North Dakota
Ohio Oklahoma Pennsylvania South Carolina Texas Utah Wisconsin
State DOTs Using GeoGauge Florida Georgia Hawaii Idaho Illinois Iowa Kansas Louisiana Maryland
Ohio Michigan Oregon Minnesota Pennsylvania Mississippi South Carolina Nevada South Dakota New Hampshire Tennessee New York Texas North Carolina Wisconsin North Dakota Wyoming
Value Engineering MnDOT TH61 “Design & Compaction Control For Foundation Soil Improvements” Paper at TRB 2004 CNA Consulting Engineers American Engineering Testing C.S. McCrossan Inc.
GeoGauge Data 50 45 40
Frequency
35 30 25 20 15 10 5 0 0
100
200
300
400
500
600
700
800
2
Modulus (tons/ft ) GeoGauge
GeoGauge Normal Distribution
900
1000
Design Build MnDOT ROC 52 Mn/DOT
Terry Ward – Project Manager
HDR – Construction Control Corporation
Doug Jackson – Project Manager Tom Wiener – Project Controls Manager
Materials QC/QA Compliance Materials database Test requirements known Field samples taken Field test results recorded Pass / fail in real time
Material Detailed Graph
Machine Control Using GPS TH 23 MnDOT Willmar District 8, Office of Technical Support, NCHRP 10-65
Intelligent Compaction “Overview and Research Needs” Presentation at TRB 2004 Jean-Louis Briaud and Jeong Bok Seo Texas A&M University ACKNOWLEDGEMENTS Chris Dumas, FHWA Hans Kloubert, BOMAG Roland Anderegg, AMMANN Carl Petterson, GEODYNAMIK
AMMANN Compaction Expert
Intelligent Compaction Economics (Briaud and Seo, 2004)
• More than 30% reduction in labor time and fuel costs • Reduce the number of conventional spot tests • Increase the roller’s useful life
Relative Continuous Testing Method (Briaud and Seo, 2004) • • • • • •
Instrumented vertical or horizontal vibrating rollers Measure roller acceleration as function of time Calculate a stiffness index Index depends on soil stiffness and roller parameters Index is compared for successive passes Relative index values help the roller operator avoid over and under compaction
Absolute Continuous Testing Method (Briaud and Seo, 2004) • • • • • •
Instrumented vertical or horizontal vibrating rollers Measure roller acceleration as a function of time Calculate a soil modulus Soil modulus is independent of the roller Soil modulus is compared to target value (specs) The soil modulus value tells the operator if the specified compaction level has been reached
Intelligent Compaction Method (Briaud and Seo, 2004)
• Instrumented vertical or horizontal vibrating rollers • Measure roller acceleration as a function of time • Calculate a soil modulus • Soil modulus is independent of the roller • The intelligent roller automatically and “instantaneously” modifies its settings (force, amplitude, frequency) to meet the target soil modulus
MnROAD CCC Demonstration September 27-29, 2004 Bomag Omann Bros Braun Intertec Sweeney Bros C.S. McCrossan CNA Consulting Engineers Federal Highway Administration Minnesota Department of Transportation
Quasi-static Plate Load Test
300
250
Load (lb)
200
150
100
50
0 0.000
0.020
0.040
0.060
0.080
0.100
Displacement (inches) 12/12/02 Test 1
12/12/02 Test 2
12/12/02 Test 3
0.120
0.140
Test Type and Equipment
Shear Strength
Dynamic Cone Penetrometer (DCP)
Elastic Modulus Falling Weight Deflectometer (FWD) Loadman Portable FWD (LWD) Prima Portable FWD (LWD) Humboldt GeoGauge Quasi-static Plate Load Bomag Compactor
Density
Sand Cone, Nuclear Gauge
Moisture Sand Cone, Nuclear Gauge Camp Stove with Scale, Kessler FMO
Quality Control Testing, Modulus vs Location MnROAD CCC Demonstration, Westbound Lane, September 29, 2004 MnDOT Class 6, 100% Crushed Granite, Poisson = 0.35 160
Modulus (MPa)
120
80
40
0 100
110
120
130
140
150
Location (feet) DCP200a3CSIR
DCP100topCSIR
LM2 loadcell
LM2 accel only
Bomag
GG after
Relative Density
160
1.6
120
1.2
80
0.8
40
0.4
0
0.0
100
110
120
130
140
150
Distance (feet) LM2 Accel
FWD low
FWD med
FWD high
LM2 stress accel
FWD stress low
FWD stress med
FWD stress high
Vertical Stress (MPa)
Modulus (MPa)
Quality Assurance Testing, Modulus vs Location MnROAD CCC Demonstration, Eastbound Lane, October 14, 2004 MnDOT Class 6, 100% Crushed Granite, Poisson = 0.35
FWD Moduli vs Peak Stress MnROAD CCC Demonstration, October 21, 2004 Class 6 Prior to Paving, Three Drop Heights Shown, Mean of Three Repetitions Shown Poisson's Ratio = 0.35, Plate Radius = 150 mm, Rigid Plate Factor = 0.79 160
y = 0.07x + 98.07 2 R = 0.57
150
Modulus (MPa)
140
130
120
110
100 0
100
200
300
400
500
600
Peak Stress (kPa) M0
M1
M2
M3
M4
M5
M6
M7
M8
Linear (M0)
700
University of Minnesota ME Projects
Mechanistic Empirical Design Seasonal Properties Dynamic Analysis of FWD MnROAD TDR Data Analysis LWD Enhancement and Verification Moisture Retention Characteristics Modulus of Select Granular Moisture Effects on DCP/LWD Unsaturated Material Resistance Factors Implementation of LWD Dynamic Analysis
1999 2000 2001 2002 2003 2004 2004 2005 2005 2005
Current/Future Standards
EU Performance Related Specifications Mn/DOT DCP Specifications Aggregate and Granular ASTM DCP Test Method ASTM GeoGauge Test Method ASTM LWD Test Method (draft) FHWA GeoGauge Pooled Fund FHWA CRREL Subgrade Performance Pooled Fund NCHRP 10-65 NDT QC/QA for Flexible Pavements Proposed DCP/LWD Specification Pooled Fund Proposed Intelligent Compaction Pooled Fund AASHTO M-E Pavement Design
Conclusions
Density testing has been useful, but is not time efficient, does not verify design properties, and should be replaced. Construction equipment and field tests are now available that can measure the mechanistic properties used to design pavements. Field data acquisition and materials reporting using global positioning systems (GPS) and geographic information systems (GIS) are available. What’s Next?
Mn/DOT TH 212 Design Build
Requests proposals to contract with a Design-Build Verification Consultant (DBVC) to provide design verification, contract administration, materials testing and construction inspection for the project.
Intelligent Compaction Evaluation
Mn/DOT TH 212 Design Build
It is believed that intelligent compaction will provide benefits for both the contractor and agency. Mn/DOT currently has little experience with this construction process. The primary objective of this effort is to determine the viability and effectiveness of intelligent compaction processes; whether it can be utilized to obtain similar, or better, compaction performance on grading, base, and asphalt construction.
Mn/DOT TH 212 Design Build
Should the design-builder elect to utilize intelligent compaction processes on the T.H. 212 Design-Build project, Mn/DOT will require that the data be collected, stored and made available to the consultant by the designbuilder. The project’s purpose is to enable Mn/DOT to evaluate the effectiveness of the process and begin to develop specification limits for future projects.
Thank you. Questions?
http://mnroad.dot.state.mn.us Research
Products
Mechanistic
Empirical Resources
Outline of Presentation Background In Situ Testing Devices Mn/DOT Case Studies Intelligent Compaction Overview Demonstration at MnROAD Conclusions
Testing for Compaction
Currently (empirical pavement design) Specify
Relative Density (Proctor Test) Specify Moisture Limits (Proctor Test) Test Rolling
Future (mechanistic pavement design) QC:
Intelligent Compaction Equipment QA: Specify Stiffness and Strength QA: Continue to Specify Moisture QA: Automated Test Rolling
Density Testing Issues Proctor Had a Different Idea ASTM Specifies Standard Compactive Effort Optimum Moisture for Compaction Strength and Stiffness May Not Be Achieved Rutting Due to Moisture and Construction Traffic
Proctor Had a Different Idea 1933 “12
inch firm blows” not
12
inch firm strokes
Proctor 1948
“This inadvertent substitution evidently led some organizations to assume that instead of striking a minimum length blow of 12 inches, the tamper should be dropped a distance of 12 inches in free fall.”
Proctor 1948 “Originally published objective of compaction in earth fills was a saturated penetration resistance of 300 lb per sq in.”
“Soil would then have twice the penetration resistance required to permit loaded truck travel when fully saturated.”
“The 12 inch blow was required principally to assure accurate determination of this penetration resistance and was never intended as a ‘standard’ or ‘optimum’.”
Nuclear vs Sandcone Densities Investigation 622, U of M, LRRB, Mn/DOT, 1966 Sandcone results have appreciable errors Greatest errors in high density granular soils More than 5 lbs per cubic foot Due to inherent errors in the sandcone procedure
Nuclear Density vs Sandcone Density Mn/ROAD Aggregate Base 1998, 1999, 2000, 2001, and 2004 145 y = 1.0x - 5.0
N u clear D en sity (lb /ft3)
2
R = 0.7 140
135
130
125 125
130
135
Sandcone Density (lb/ft3)
140
145
Nuclear Compaction vs Sandcone Compaction Mn/ROAD Aggregate Base 1998, 1999, 2000, 2001, and 2004
Nuclear Compaction (percent)
110
105
100
95 95
100
105
Sandcone Compaction (percent)
110
Nuclear Moisture vs Sandcone Moisture Mn/ROAD Aggregate Base 1998, 1999, 2000, 2001, and 2004
N u clear M o istu re (p ercen t)
10
8
6 y = 0.98x + 0.20 2
R = 0.93 4
2 2
4
6
Sandcone Moisture (percent)
8
10
Proctor 1948
The most essential link between theoretical and practical soil mechanics is the collection of better data regarding the compaction equipment and methods required to produce the prescribed shear strengths.
“For in the final analysis, all laboratory and experimental data is just about worthless unless the results secured actually can be applied to the work, a condition that at present is rare.”
New In Situ Tests Are Needed
Achieve agreement between construction quality assurance and seasonal pavement design.
Quantify alternative materials and construction practices. Show economic benefit of improved materials. Reward good construction.
This requires new specifications and new tools. Tools must be quantitative, portable, and accurate in the field.
In Situ Testing Equipment
DCP and Backcalculated FWD Moduli vs Stationing Waseca Co Rd 8, April 7, 2000 Subgrade Below Flyash 100
80
60
40
20
0 1000
2000
3000
4000
Stationing DCP 6 Inch Avg
FWD lowest drop
5000
6000
PRIMA Portable FWD (LWD)
Impulse Device Load
measured Velocity measured Deflection calculated Variable falling mass Variable plate size
Humboldt GeoGauge
State DOTs Using DCP California Colorado Florida Idaho Illinois Iowa Kansas Kentucky Maryland
Massachusetts Michigan Minnesota Mississippi Missouri Montana New Jersey North Carolina North Dakota
Ohio Oklahoma Pennsylvania South Carolina Texas Utah Wisconsin
State DOTs Using GeoGauge Florida Georgia Hawaii Idaho Illinois Iowa Kansas Louisiana Maryland
Ohio Michigan Oregon Minnesota Pennsylvania Mississippi South Carolina Nevada South Dakota New Hampshire Tennessee New York Texas North Carolina Wisconsin North Dakota Wyoming
Value Engineering MnDOT TH61 “Design & Compaction Control For Foundation Soil Improvements” Paper at TRB 2004 CNA Consulting Engineers American Engineering Testing C.S. McCrossan Inc.
GeoGauge Data 50 45 40
Frequency
35 30 25 20 15 10 5 0 0
100
200
300
400
500
600
700
800
2
Modulus (tons/ft ) GeoGauge
GeoGauge Normal Distribution
900
1000
Design Build MnDOT ROC 52 Mn/DOT
Terry Ward – Project Manager
HDR – Construction Control Corporation
Doug Jackson – Project Manager Tom Wiener – Project Controls Manager
Materials QC/QA Compliance Materials database Test requirements known Field samples taken Field test results recorded Pass / fail in real time
Material Detailed Graph
Machine Control Using GPS TH 23 MnDOT Willmar District 8, Office of Technical Support, NCHRP 10-65
Intelligent Compaction “Overview and Research Needs” Presentation at TRB 2004 Jean-Louis Briaud and Jeong Bok Seo Texas A&M University ACKNOWLEDGEMENTS Chris Dumas, FHWA Hans Kloubert, BOMAG Roland Anderegg, AMMANN Carl Petterson, GEODYNAMIK
AMMANN Compaction Expert
Intelligent Compaction Economics (Briaud and Seo, 2004)
• More than 30% reduction in labor time and fuel costs • Reduce the number of conventional spot tests • Increase the roller’s useful life
Relative Continuous Testing Method (Briaud and Seo, 2004) • • • • • •
Instrumented vertical or horizontal vibrating rollers Measure roller acceleration as function of time Calculate a stiffness index Index depends on soil stiffness and roller parameters Index is compared for successive passes Relative index values help the roller operator avoid over and under compaction
Absolute Continuous Testing Method (Briaud and Seo, 2004) • • • • • •
Instrumented vertical or horizontal vibrating rollers Measure roller acceleration as a function of time Calculate a soil modulus Soil modulus is independent of the roller Soil modulus is compared to target value (specs) The soil modulus value tells the operator if the specified compaction level has been reached
Intelligent Compaction Method (Briaud and Seo, 2004)
• Instrumented vertical or horizontal vibrating rollers • Measure roller acceleration as a function of time • Calculate a soil modulus • Soil modulus is independent of the roller • The intelligent roller automatically and “instantaneously” modifies its settings (force, amplitude, frequency) to meet the target soil modulus
MnROAD CCC Demonstration September 27-29, 2004 Bomag Omann Bros Braun Intertec Sweeney Bros C.S. McCrossan CNA Consulting Engineers Federal Highway Administration Minnesota Department of Transportation
Quasi-static Plate Load Test
300
250
Load (lb)
200
150
100
50
0 0.000
0.020
0.040
0.060
0.080
0.100
Displacement (inches) 12/12/02 Test 1
12/12/02 Test 2
12/12/02 Test 3
0.120
0.140
Test Type and Equipment
Shear Strength
Dynamic Cone Penetrometer (DCP)
Elastic Modulus Falling Weight Deflectometer (FWD) Loadman Portable FWD (LWD) Prima Portable FWD (LWD) Humboldt GeoGauge Quasi-static Plate Load Bomag Compactor
Density
Sand Cone, Nuclear Gauge
Moisture Sand Cone, Nuclear Gauge Camp Stove with Scale, Kessler FMO
Quality Control Testing, Modulus vs Location MnROAD CCC Demonstration, Westbound Lane, September 29, 2004 MnDOT Class 6, 100% Crushed Granite, Poisson = 0.35 160
Modulus (MPa)
120
80
40
0 100
110
120
130
140
150
Location (feet) DCP200a3CSIR
DCP100topCSIR
LM2 loadcell
LM2 accel only
Bomag
GG after
Relative Density
160
1.6
120
1.2
80
0.8
40
0.4
0
0.0
100
110
120
130
140
150
Distance (feet) LM2 Accel
FWD low
FWD med
FWD high
LM2 stress accel
FWD stress low
FWD stress med
FWD stress high
Vertical Stress (MPa)
Modulus (MPa)
Quality Assurance Testing, Modulus vs Location MnROAD CCC Demonstration, Eastbound Lane, October 14, 2004 MnDOT Class 6, 100% Crushed Granite, Poisson = 0.35
FWD Moduli vs Peak Stress MnROAD CCC Demonstration, October 21, 2004 Class 6 Prior to Paving, Three Drop Heights Shown, Mean of Three Repetitions Shown Poisson's Ratio = 0.35, Plate Radius = 150 mm, Rigid Plate Factor = 0.79 160
y = 0.07x + 98.07 2 R = 0.57
150
Modulus (MPa)
140
130
120
110
100 0
100
200
300
400
500
600
Peak Stress (kPa) M0
M1
M2
M3
M4
M5
M6
M7
M8
Linear (M0)
700
University of Minnesota ME Projects
Mechanistic Empirical Design Seasonal Properties Dynamic Analysis of FWD MnROAD TDR Data Analysis LWD Enhancement and Verification Moisture Retention Characteristics Modulus of Select Granular Moisture Effects on DCP/LWD Unsaturated Material Resistance Factors Implementation of LWD Dynamic Analysis
1999 2000 2001 2002 2003 2004 2004 2005 2005 2005
Current/Future Standards
EU Performance Related Specifications Mn/DOT DCP Specifications Aggregate and Granular ASTM DCP Test Method ASTM GeoGauge Test Method ASTM LWD Test Method (draft) FHWA GeoGauge Pooled Fund FHWA CRREL Subgrade Performance Pooled Fund NCHRP 10-65 NDT QC/QA for Flexible Pavements Proposed DCP/LWD Specification Pooled Fund Proposed Intelligent Compaction Pooled Fund AASHTO M-E Pavement Design
Conclusions
Density testing has been useful, but is not time efficient, does not verify design properties, and should be replaced. Construction equipment and field tests are now available that can measure the mechanistic properties used to design pavements. Field data acquisition and materials reporting using global positioning systems (GPS) and geographic information systems (GIS) are available. What’s Next?
Mn/DOT TH 212 Design Build
Requests proposals to contract with a Design-Build Verification Consultant (DBVC) to provide design verification, contract administration, materials testing and construction inspection for the project.
Intelligent Compaction Evaluation
Mn/DOT TH 212 Design Build
It is believed that intelligent compaction will provide benefits for both the contractor and agency. Mn/DOT currently has little experience with this construction process. The primary objective of this effort is to determine the viability and effectiveness of intelligent compaction processes; whether it can be utilized to obtain similar, or better, compaction performance on grading, base, and asphalt construction.
Mn/DOT TH 212 Design Build
Should the design-builder elect to utilize intelligent compaction processes on the T.H. 212 Design-Build project, Mn/DOT will require that the data be collected, stored and made available to the consultant by the designbuilder. The project’s purpose is to enable Mn/DOT to evaluate the effectiveness of the process and begin to develop specification limits for future projects.
Thank you. Questions?
http://mnroad.dot.state.mn.us Research
Products
Mechanistic
Empirical Resources
