intelligent compaction - texas department of...

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

QUESTIONS?

Jimmy Si, Ph.D., P.E.

512-506-5901

Jimmy.Si@txdot.gov

Thank You!