INTELLIGENT COMPACTION

Transcription

1 INTELLIGENT COMPACTION Directions to the Future Jimmy Si, Ph.D., P.E. San Antonio, TX, Mar. 20, 2014

2 Table of Contents 1 What Is Intelligent Compaction Why Use Intelligent Compaction National and TXDOT IC Projects What We Learned 16 5 Benefits and Challenges Future Plans 19 7 Quiz 20 2

3 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 GPS Receiver Display Panel 3

4 Technology Caterpillar: CMV, MDP Dynapac: CMV Bomag: E VIB (MN/m²) Sakai: CCV Case/Ammann: k b (MN/m) Hamm: HMV 4

5 TxDOT Retrofit Kit Installation Accelerometer Trimble IC Retrofit Kit (outside) Display Panel Trimble IC Retrofit Kit (inside) Receiver Radio Base Station 5

6 Why Use IC? Ordinary Compaction Density Control Compactive Energy Moisture Content Material Type Compact Lift Thickness Underlying Conditions 6

7 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 Can We Do A Better Job? 7

8 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 Before After 8

9 National Perspective AK HI WA OR NV CA ID UT AZ MT WY CO NM ND SD NE KS OK MN WI IA MO AR IL MS MI OH IN KY TN AL GA PA WV VA NC SC VT NY ME NH MA RI CT NJ DE MD DC National Leaders TX LA 34 States Exploring IC 2012 less than 20 projects 2013 approximately 50 projects 2014 projected 150 projects FL PR 9

10 TxDOT IC Projects El Paso (1) FM1281 Amarillo (1) LP335 Fort Worth (8) FM156; DFW Connector; US287 ; FM1938; FM731; SH267; IH35W; and IH30 Paris (2) US75 SH24 Atlanta (1) FM450 Houston (1) SH35 10

11 FM156 Project FM156, Fort Worth, TX FHWA/TPF IC Study SG, Lime Stabilized SG, and Flex Base Ammann/Case padfoot drum IC roller Ammann/Case smooth drum IC roller Dynapac single smooth drum IC roller 11

12 FM156 Project Identify Soft Spots K s shows compaction progress and a soft spot Screen shots of k SΙPD maps for different passes on TB 1 Case/Ammann single-drum padfoot IC roller 12

13 FM156 Project Identify Underground Structures and Soft Area 0 0 Point 12 Depth (mm) Point 13 E LWD-Z2 = 47.5 MPa E V1 = 42.1 MPa E V2 = MPa E FWD-D3 = 57 MPa E D-SPA = 44 MPa Point 13 Depth (mm) DCP refusal (Box Culvert) E LWD-Z2 = 58.4 MPa E V1 = 96.9 MPa E V2 = MPa E FWD-D3 = 145 MPa E D-SPA = 88 MPa Point CBR (%) CBR (%) 0 Point 5 Point Depth (mm) w = 29.5% g d = 13.8 kn/m 3 E LWD-Z2 = 11.6 MPa Box Culvert Point CBR (%) Depth (mm) w = 20.8% g d = 16.0 kn/m 3 E LWD-Z2 = 61.1 MPa 800 Point 1 Case/Ammann single-drum padfoot IC roller CBR (%) 13

14 FM156 Project - Padfoot vs. Smooth Drum Spatial comparison of k SΙPD and k SΙSD maps (TB 1 subgrade clay material) k SISD (MN/m) Padfoot a = 0.8 mm, f = 35 Hz Smoothdrum a = 1.1 mm, f = 30 Hz Padfoot a = 1.3 mm, f = 35 Hz Smoothdrum a = 1.1 mm, f = 30 Hz Padfoot a = 1.0 mm, f = 35 Hz Smoothdrum a = 1.5 mm, f = 35 Hz Padfoot vs. Smooth Drum k SIPD (MN/m) 14

15 FM156 Project IC vs. Conventional Tests IC data vs. Conventional Tests (NDG, LWD, DCP, FWD) DCP LWD Box culvert at 8 in. depth FWD 15

16 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 Soft ground condition = hard to push Firm ground condition = easy to push 16

17 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

18 Challenges 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 18

19 Future Plans 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

20 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

21 Thank You! QUESTIONS? Jimmy Si, Ph.D., P.E