understanding the technology intelligent compaction jimmy si, ph.d., p.e. austin, tx, april 3, 2014
TRANSCRIPT
Understanding the Technology
INTELLIGENT COMPACTION
Jimmy Si, Ph.D., P.E. Austin, TX, April 3, 2014
Table of Contents
6-9
10-11
12
13
3-5Why Use Intelligent Compaction
TXDOT IC Projects
Benefits and Challenges
Future Plans
Summary
1
2
3
4
5
2
Ordinary Compaction
Density Control
• Compactive Energy
• Moisture Content
• Material Type
• Compact Lift Thickness
• Underlying Conditions
Why Use IC?
3
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
4
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
5
Before
After
TxDOT IC ProjectsFort Worth (7)FM156; US287 ; FM1938;
FM731; SH267; IH35W;
and IH30
El Paso (1)FM1281
Amarillo (1)LP335
Paris (2)US75SH24
Atlanta (1)FM450
Houston (1)SH35
6
FM156, Fort Worth, TX
FHWA/TPF IC Study
SG, Lime Stabilized SG, and Flex Base
Ammann/Case padfoot drum IC roller
Dynapac singlesmooth drum IC roller
Ammann/Case smooth drum IC roller
FM156 Project
7
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
8
FWD
LWD
FM156 Project – IC vs. Conventional Tests
DCP
9
Benefits
Covers 100% of the area compacted
Monitors pass counts Identifies areas of poor compaction Intelligently picks areas to test for QC/QA Improves productivity and minimizes cost Improves safety in construction zones
10
Extensive training for DOT and contractors FHWA training workshops
Data management difficulties VEDA
More expensive than ordinary IC retrofit kit
High moisture variation No strong correlation b/w stiffness and density
Challenges
11
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
12
Future Plans
Summary
1. IC is a continuous compaction control process.
2. IC is only for QC so far.
3. IC measures stiffness, not density.
4. IC reports both stiffness and pass count.
5. IC does not measure moisture.
6. IC measurements are sensitive to moisture.
7. IC improves safety in construction zones.
13
