Use of Lime Activated Class F Fly Ash for Full Depth Reclamation (FDR) of Asphalt Pavements

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1 Use of Lime Activated Class F Fly Ash for Full Depth Reclamation (FDR) of Asphalt Pavements William Wolfe, Tarunjit Butalia, Harold Walker Ryan Mackos, Gursimran Singh, James Howdyshell The Ohio State University

2 Objective Demonstrate effective use of Class F fly ash in combination with lime or lime kiln dust (LKD) in Full Depth Reclamation of asphalt pavements. Introduction Construction Instrumentation Monitoring Conclusions

3 Coal Use Facts Nationally: 52% of Electricity is Generated by Combustion of Coal 1.1 Billion Tons were consumed in State of Ohio: 90% of Ohio s Electricity is Generated by Combustion of Coal Coal Use: 30 Million Tons/Yr. (Ohio Coal) 30 Million Tons/Yr. (Non-Ohio Coal) 1.5 Tons of Coal Combustion By-products generated in Ohio / Person / Yr. Introduction Construction Instrumentation Monitoring Conclusions

4 Coal Fired Fly Ash Generating Power Plants 50 mile radius Introduction Construction Instrumentation Monitoring Conclusions

5 FDR Sites Introduction Construction Instrumentation Monitoring Conclusions

6 Pavement Instrumentation Plan

7 Warren County Pavement Sections (0.4 miles) Two sections were designed and constructed (2006): Station 1: 5 inch Mill and Fill (0.08 mile) Station 2: 4% Lime with 6% Fly Ash,, 12 inch stabilization depth (0.32 mile) Introduction Construction Instrumentation Monitoring Conclusions

8 Pavement Instrumentation Plan Warren County Station 1 (Mill & Fill) 2 (Lime & Fly Ash) Sensors Installed Longitudinal and Transverse Strain Gauges Lysimeter Longitudinal and Transverse Strain Gauges, Pressure Cell, LVDTs, Lysimeter, Tensiometer

9 Section Line Rd. Station Layout Delaware County Introduction Construction Instrumentation Monitoring Conclusions

10 Delaware County Pavement Sections (4.1 miles) Nine sections were designed and constructed (2006) using the following six mixes: Station 1: 2% Cement with 1.6 gallons per square yard emulsion,, 8 inch stabilization depth (0.3 mile) Station 2: 5% Cement,, 12 inch stabilization depth (0.8 mile) Station 3: 3% Lime Kiln Dust with 1.4 gallons per square yard emulsion, 8 inch stabilization depth (0.7 mile) Station 4: 5 inch Mill and Fill (Two 0.1 mile sections at the north and south ends of the project, and a 0.7 mile as well as 0.1 mile sections near the middle of the project) Station 5: 5% Lime Kiln Dust with 5% Fly Ash,, 8 inch stabilization depth (0.6 mile) Station 6: 4% Lime with 6% Fly Ash,, 8 inch stabilization depth (0.7 mile) Introduction Construction Instrumentation Monitoring Conclusions

11 Pavement Instrumentation Plan Delaware County Station Sensors Installed 1 (Cement & Emulsion) 2 (Cement) 3 (LKD & Emulsion) 4 (Mill & Fill) 5 (LKD & Fly Ash) 6 (Lime & Fly Ash) Longitudinal and Transverse Strain Gauges Lysimeter Longitudinal and Transverse Strain Gauges Lysimeter Longitudinal and Transverse Strain Gauges Lysimeter Longitudinal and Transverse Strain Gauges Lysimeter Longitudinal and Transverse Strain Gauges, Pressure Cell, LVDTs, Lysimeter, Tensiometer Longitudinal and Transverse Strain Gauges, Pressure Cell, LVDTs, Lysimeter, Tensiometer

12 Falling Weight Deflectometer (FWD) Testing by Ohio DOT Delaware site before FDR

13 Average Backcalculated Moduli of FDR Layer from FWD Testing 07/06 - Before FDR (Delaware County) Open graded cement stabilized aggregate 10/06-3 weeks after FDR 04/07-7 months after FDR 07/07-10 months after FDR 10/07-13 months after FDR Elastic Modulus of base layer (ksi) Soil cement Lime stabilized soils or unstabilized dense graded aggregate 0 S1, Cement + Emulsion Typical Resilient Modulus values (Mechanistic Empirical Pavement Design Guide 2004, FHWA) Outlying data points removed S2, Cement S3, LKD + Emulsion S4, Control S5, LKD + fly ash S6, Lime + fly ash

14 0 5 Deflections Under Applied Loading from FWD Testing (Delaware County Northbound Lane) Section 1 Cement & Emulsion Section 2 Cement Section 3 LKD & Emulsion Location (miles form start) Section 4 Control Section 5 LKD & Fly Ash Section 6 Lime & Fly Ash Deflection (mils) /06 - Before FDR 10/06-3 weeks after FDR 04/07-7 months after FDR 07/07-10 months after FDR 10/07-13 months after FDR 45 50

15 Average Backcalculated Moduli of FDR Layer from FWD Testing (Warren County) Open graded cement stabilized aggregate* Elastic Modulus of base layer (ksi) Soil cement* Lime stabilized soils or unstabilized dense graded aggregate* 07/06 - Before FDR 09/06-3 weeks after FDR 11/06-3 months after FDR 04/07-8 months after FDR 07/07-11 months after FDR 10/07-14 months after FDR S2, fly ash and lime (0.32 mi) S1, control (0.08 mi) Section Typical Resilient Modulus values (Mechanistic Empirical Pavement Design Guide 2004, FHWA) Outlying data points were removed

16 Deflections Under Applied Loading from FWD Testing (Warren County Eastbound Lane) Location (miles from start) Deflection (mils) /06 - Before FDR 09/06-3 weeks after FDR 11/06-3 months after FDR 04/07-8 months after FDR 07/07-11 months after FDR 10/07-14 months after FDR Section 2 Fly Ash & Lime Section 1 Control

17 Longitudinal Strain Data from Delaware County 12/06 45 mph APLF maximum 65 micorstain Station 1 - Cement & Emulsion Station 2 - Cement Station 3 - LKD & Emulsion Station 4 - Control Station 5 - LKD & Fly Ash Longitudinal Strain APLF minimum 40 micorstain Station 6 - Lime & Fly Ash Time (10-2 sec)

18 Transverse Strain Data from Delaware County 12/06 45 mph APLF maximum 75 microstrain Station 1 - Cement & Emulsion Station 2 - Cement Station 3 - LKD & Emulsion Station 4 - Control Station 5 - LKD & Fly Ash Station 6 - Lime & Fly Ash Transverse Strain APLF minimum 65 microstrain Time (10-2 sec)

19 Total Deflections: Delaware County - 15 mph v 45 mph Station 5 (5% LKD with 5% Fly Ash) APLF maximum in. 15 mph 45 mph Deflection (in) APLF minimum in Time (10-2 seconds)

20 Deflection of Unreclaimed Base: Delaware County Station 5 (5% LKD with 5% Fly Ash) Deflection (in) mph 15 mph Time (10-2 seconds)

Pressure Cell Data from Delaware County 45 mph 35 30 25 Range of stresses from APLF St.

21 Pressure Cell Data from Delaware County 45 mph Range of stresses from APLF St. 5-5% LKD & 5% Fly Ash St. 6-4% Lime & 6% Fly Ash Vertical Stress (kpa) Time (10-2 sec)

22 Environmental Objectives Demonstrate CCPs can be incorporated into FDR mixes in an environmentally sound manner. Characterize environmental properties for various mixes (lab) Elemental composition TCLP/SPLP Leachate Field Monitoring Warren County Delaware County

23 Toxicity Characteristic Leaching Procedure Data Warren County Delaware County Analyte CCP Control Section 1 Section 3 Section 5 Section 6 Aluminum ND ND ND ND ND ND Arsenic (Limit=5.0 mg/l) Barium Calcium Cadmium (Limit=1.0 mg/l) BDL BDL BDL BDL BDL BDL Chromium (Limit=5.0 mg/l) BDL BDL BDL BDL BDL BDL Copper BDL BDL Iron BDL Lead (Limit=5.0 mg/l) ND ND ND ND Potassium ND ND ND ND ND ND Magnesium BDL Manganese ND ND BDL Mercury (Limit=0.2 mg/l) <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Molybdenum BDL BDL BDL Nickel BDL BDL Selenium (Limit=1.0 mg/l) Silicon 4 ND 23 BDL 8 13 Sodium Strontium Sulfur Zinc BDL BDL BDL BDL BDL BDL All values given in units of mg/l. BDL= Below Detection Limit Limits = Hazardous Waste Limit

24 Synthetic Precipitation Leaching Procedure Data Warren County Delaware County Analyte CCP Control Section 1 Section 6 Aluminum ND ND ND ND Arsenic (Limit=5.0 mg/l) < <0.001 <0.001 Barium Calcium Cadmium (Limit=1.0 mg/l) BDL BDL BDL BDL Chromium (Limit=5.0 mg/l) BDL BDL BDL BDL Copper BDL BDL BDL BDL Iron BDL BDL BDL BDL Lead (Limit=5.0 mg/l) ND ND ND Potassium ND ND ND ND Magnesium BDL ND BDL BDL Manganese BDL BDL BDL BDL Mercury (Limit=0.2 mg/l) <0.001 <0.001 <0.001 <0.001 Molybdenum BDL BDL BDL BDL Nickel BDL BDL BDL BDL Selenium (Limit=1.0 mg/l) <0.001 <0.001 <0.001 <0.001 Silicon Sodium Strontium Sulfur Zinc ND ND ND All values given in units of mg/l. BDL= Below Detection Limit Limits = Hazardous Waste Limit

25 Environmental Sampling Procedure Sampling Procedures Samples are obtained on a monthly basis. A vacuum pump is attached to the polyethylene tubing. Approximately 1-2 hours are spent at each site.

26 Field Sampling Results Site Samples Obtained Trips Warren Control 5 12 Warren CCP Section 1 12 Delaware # Delaware #2 0 7 Delaware # Delaware # Delaware #5 0 7 Delaware #6 0 13

27 Warren County Sampling Data Analyte EPA MCL CCP Section Control Aluminum - BDL Arsenic <0.001 Barium Calcium Cadmium BDL BDL Chromium BDL BDL Copper 1.3 ND Iron Lead BDL BDL Potassium Magnesium Manganese - BDL BDL Mercury <0.001 <0.001 Molybdenum - ND ND Nickel - BDL Selenium BDL <0.001 Silicon Sodium Strontium Sulfur Zinc All data given in units of mg/l. Maximum values obtained over the course of sampling. BDL= Below Detection Limit ND= Not Determined MCL = Maximum Contaminant Level

28 Delaware County Sampling Data Analyte EPA MCL Section 1 Section 2 Section 3 Section 4 Section 5 Section 6 Aluminum BDL Arsenic < Barium Calcium BDL Cadmium BDL - BDL BDL - - Chromium BDL BDL - - Copper Iron Lead BDL - BDL BDL - - Potassium Magnesium Manganese - BDL BDL - - Mercury < <0.001 < Molybdenum - ND - ND ND - - Nickel Selenium <0.001 <0.001 <0.001 Silicon Sodium Strontium Sulfur Zinc All data given in units of mg/l. Maximum values obtained over the course of sampling. Sections 2, 5, and 6 never produced enough water to do all the analysis procedures. BDL= Below Detection Limit ND= Not Determined MCL = Maximum Contaminant Level

29 Leachate study of high fly ash content concrete samples Plain Concrete 30% Fly Ash 50% Fly Ash Non-toxic TCLP ASTM SPLP TCLP ASTM SPLP TCLP ASTM SPLP Criteria ph inital ph finish Al As <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 < B < < Ba Ca Cd <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 < Cr <0.005 < < <0.005 < Cu 0.02 <0.001 < <0.001 < <0.001 <0.001 Fe Hg <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 K Mg Mn <0.001 < <0.001 < <0.001 <0.001 Mo Na Ni < < <0.01 Pb <0.006 < <0.006 <0.01 <0.006 <0.006 <0.01 S Se <0.001 <0.001 <0.002 <0.001 <0.001 <0.002 < < Si Sr Zn < < <0.005 <0.005 Unit: mg/l

8 inches (stabilization depth) 5% LKD with 5% Fly Ash

30 2007 Zanesville Shoulder Reclamation: North Pointe Road (1,000 feet) Reclaimed 1000 ft long 8 feet wide shoulder to 8 inches (stabilization depth) 5% LKD with 5% Fly Ash Conditioned Fly Ash (m/c( about 20%) Glatfelter paper plant (Chillicothe)

(Conesville( power plant), 8 inch stabilization depth (2.

31 2007 Zanesville Road Reclamation: Friendly Hills Road (2.2 miles) Two sections were constructed (2007) using the following mixes: 5% LKD with 5% Conditioned Fly Ash (Conesville( power plant), 8 inch stabilization depth (2.1 mile) 10% Fixated FGD material (Conesville( power plant), 8 inch stabilization depth (0.1 mile) Instrumented with pore pressure transducers just below FDR base. Chip and seal completed mid-september 2007 Fly Ash Section Fixated FGD Section

32 Conclusions: Delaware & Warren Co Sites (after 15 months) Pavement sections stabilized with fly ash (+LKD/lime) showed comparable stiffness and strength to the cement stabilized sections. The use of fly ash (with LKD or lime) as substitute for traditional cementitous additives in FDR can result in substantial cost savings as well as additional significant environmental benefits Fly ash can be easily mixed and compacted using standard FDR construction equipment.

33 Continuing Efforts Ongoing pavement performance and environmental condition measurements obtained from long-term monitoring and testing. Analytical studies, numerical modeling.

34 Structural Layer Coefficients Delaware County - Section Line Rd. Section Cement & Emulsion Cement LKD & Emulsion Mill & Fill LKD & Fly Ash Lime & Fly Ash Date M R (psi) a i M R (psi) a i M R (psi) a i M R (psi) a i M R (psi) a i M R (psi) a i 07/ Before FDR / Weeks / months / months / months Warren County - Long Spurling Rd. Section 1 2 Mill & Fill Lime & Fly Ash KEY Date M R (psi) a i M R (psi) a i 07/ M R (psi) a i Before FDR Reults from AASHTO 09/ MODCOMP5 Huang Weeks / AASHTO: a i = 0.14*(M R /30,000) 1/ months / Huang: a i = 0.29(log M R ) months / months / months

Acknowledgements Ohio Coal Development Office / Ohio Air Quality Development Authority Delaware County Engineer s Office Warren County Engineer's Office Muskinghum County Engineer s

35 Acknowledgements Ohio Coal Development Office / Ohio Air Quality Development Authority Delaware County Engineer s Office Warren County Engineer's Office Muskinghum County Engineer s Office Ohio DOT Base Construction Fly Ash Direct Headwater Resources Carmeuse NA Mintek Resources EDP Consultants Asphalt Recycling and Reclamation Association American Coal Ash Association

36 Recent Articles Asphalt Contractor, February 2007 Roads & Bridges, May 2007 Better Roads, July 2007 Ash at Work, August 2007 USEPA C2P2 Case Study 16, Fall 2007

Full-Depth Reclamation of Asphalt Pavements Using Lime-Activated Class F Fly Ash: Structural Monitoring Aspects

2009 World of Coal Ash (WOCA) Conference - May 4-7, 2009 in Lexington, KY, USA http://www.flyash.info/ Full-Depth Reclamation of Asphalt Pavements Using Lime-Activated Class F Fly Ash: Structural Monitoring