Directions to the Future
INTELLIGENT COMPACTION
Jimmy Si, Ph.D., P.E. San Antonio, TX, Mar. 20, 2014
Table of Contents
6-8
9-15
16
17-18
3-5 What Is Intelligent Compaction
Why Use Intelligent Compaction
National and TXDOT IC Projects
What We Learned
Benefits and Challenges
1
2
3
4
5
2
Future Plans 6 19
Quiz 7 20
3
GPS
Receiver
Display
Panel
What Is Intelligent Compaction (IC)?
Vibratory rollers equipped with a stiffness measurement system that continuously measures and reports the material’s stiffness in real time during compaction
GPS-based recording and documentation system that continuously displays a color-coded map of stiffness and roller’s location in real time during compaction
Technology
Caterpillar: CMV, MDP
Dynapac: CMV
Bomag: EVIB (MN/m²)
Sakai: CCV
Case/Ammann: kb (MN/m)
4
Hamm: HMV
TxDOT Retrofit Kit Installation
5
Accelerometer
Base Station Radio Receiver
Display Panel
Trimble IC Retrofit Kit (outside)
Trimble IC Retrofit Kit (inside)
Ordinary Compaction
Density Control • Compactive Energy
• Moisture Content
• Material Type
• Compact Lift Thickness
• Underlying Conditions
Why Use IC?
6
Why Use IC?
Not used in pavement design
A layer-specific spot test providing no info on the uniformity of compaction over the entire section
Only measured after compaction is complete providing no feedback in real time
7
Can We Do A Better Job?
Why Use IC?
Lose the track of rolling pass counts Compaction job becomes guesswork
Inconsistent and non-uniform density
Under/over compaction
Premature pavement failure
8
Before
After
NH
RI
CA
AZ
CO
NM
TX
OK AR
LA
MO KY
AL GA
FL
VA
OH
MI
VT AK
MT
NV
ME
WA
OR
UT
KS
ID WY
ND
SD
MN
NE
WI
IA
IL IN
MS
TN
SC
NC
WV
PA
NY
CT
NJ
DE
MD
DC
MA
CA
HI
PR
34 States Exploring IC
National Leaders
National Perspective
9
2012 – less than 20 projects 2013 – approximately 50 projects 2014 – projected 150 projects
TxDOT IC Projects
Fort Worth (8)
FM156; DFW Connector;
US287 ; FM1938; FM731;
SH267; IH35W; and IH30
El Paso (1) FM1281
Amarillo (1) LP335
Paris (2) US75 SH24
Atlanta (1) FM450
Houston (1) SH35
10
FM156, Fort Worth, TX
FHWA/TPF IC Study
SG, Lime Stabilized SG, and Flex Base
Ammann/Case
padfoot drum IC roller
Dynapac single
smooth drum IC roller Ammann/Case
smooth drum IC roller
FM156 Project
11
Case/Ammann
single-drum
padfoot IC roller
Ks shows compaction progress and a soft spot
FM156 Project – Identify Soft Spots
Screen shots of kSΙPD maps for different passes on TB 1
12
CBR (%)
0 10 20 30 40 50 60
Dep
th (m
m)
0
200
400
600
800
Point 13
CBR (%)
0 10 20 30 40 50 60
Dep
th (m
m)
0
200
400
600
800
Point 12
DCP refusal(Box Culvert)
CBR (%)
0 10 20 30 40 50 60
Dep
th (m
m)
0
200
400
600
800
Point 5
CBR (%)
0 10 20 30 40 50 60
Dep
th (m
m)
0
200
400
600
800
Point 1
Point 1
Point 5
Point 12
Point 13
w = 29.5%g d = 13.8 kN/m3
ELWD-Z2 = 11.6 MPa
ELWD-Z2 = 58.4 MPaEV1 = 96.9 MPaEV2 = 381.1 MPaEFWD-D3 = 145 MPaED-SPA = 88 MPa
w = 20.8%g d = 16.0 kN/m3
ELWD-Z2 = 61.1 MPa
ELWD-Z2 = 47.5 MPaEV1 = 42.1 MPaEV2 = 121.1 MPaEFWD-D3 = 57 MPaED-SPA = 44 MPa
Box Culvert
Case/Ammann single-drum padfoot IC roller
FM156 Project – Identify Underground Structures and Soft Area
13
Spatial comparison of kSΙPD and kSΙSD maps
(TB 1 – subgrade clay material)
FM156 Project - Padfoot vs. Smooth Drum
14
kSIPD (MN/m)
0 10 20 30 40 50 60 70 80
k SIS
D (M
N/m
)
0
10
20
30
40
50
60
70
80Padfoot a = 0.8 mm, f = 35 HzSmoothdrum a = 1.1 mm, f = 30 HzPadfoot a = 1.3 mm, f = 35 HzSmoothdrum a = 1.1 mm, f = 30 HzPadfoot a = 1.0 mm, f = 35 HzSmoothdrum a = 1.5 mm, f = 35 Hz
Padfoot vs. Smooth Drum
IC data vs. Conventional Tests (NDG, LWD, DCP, FWD)
FWD
LWD
FM156 Project – IC vs. Conventional Tests
Box culvert at 8 in. depth
DCP
15
What We Learned
IC for QC only Identify soft spots and know when to stop rolling Padfoot and smooth drum IC rollers produce results
that are comparable and repeatable Test strips are hard to implement and may not be
necessary if for QC only. MDP is not sensitive to pick up soft areas
16
Soft ground condition = hard to push
Firm ground condition = easy to push
Benefits
Covers 100% of the area compacted
Monitors pass count
Identifies areas of poor compaction Intelligently picks areas to test for QC/QA Improves productivity and minimizes cost Improves safety in construction zones
17
Extensive training for DOT and contractors Data management difficulties More expensive than ordinary High variation of field moisture No strong correlation b/w stiffness and density Lack of IC industry standardization and
specification
Challenges
18
Workshops/Webinars and pilot projects in districts
Revise IC specification –Short Term: density based on
IC proof mapping –Long Term: stiffness based on
IC proof mapping
19
Future Plans
Quiz
1. IC is a CCC process. 2. IC is for both QC and QA. 3. IC measures both stiffness and density. 4. IC measures both stiffness and moisture. 5. IC measures both stiffness and pass count. 6. IC measurements are sensitive to moisture. 7. IC improves safety in construction zones.
20
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