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
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
Coal Use Facts Nationally: 52% of Electricity is Generated by Combustion of Coal 1.1 Billion Tons were consumed in 2005. 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
Coal Fired Fly Ash Generating Power Plants 50 mile radius Introduction Construction Instrumentation Monitoring Conclusions
2006 2007 2006 FDR Sites Introduction Construction Instrumentation Monitoring Conclusions
Pavement Instrumentation Plan
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
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
Section Line Rd. Station Layout Delaware County Introduction Construction Instrumentation Monitoring Conclusions
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
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
Falling Weight Deflectometer (FWD) Testing by Ohio DOT Delaware site before FDR
Average Backcalculated Moduli of FDR Layer from FWD Testing 07/06 - Before FDR (Delaware County) 1400 1200 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) 1000 800 600 400 200 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
0 5 Deflections Under Applied Loading from FWD Testing (Delaware County Northbound Lane) 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 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 10 15 Deflection (mils) 20 25 30 35 40 07/06 - 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
Average Backcalculated Moduli of FDR Layer from FWD Testing (Warren County) 2000 1800 Open graded cement stabilized aggregate* Elastic Modulus of base layer (ksi) 1600 1400 1200 1000 800 600 400 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 200 0 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
Deflections Under Applied Loading from FWD Testing (Warren County Eastbound Lane) Location (miles from start) 0 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 10 Deflection (mils) 20 30 40 50 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 60 70 80 Section 2 Fly Ash & Lime Section 1 Control
Longitudinal Strain Data from Delaware County 12/06 45 mph 0.00008 0.00007 APLF maximum 65 micorstain Station 1 - Cement & Emulsion Station 2 - Cement Station 3 - LKD & Emulsion 0.00006 Station 4 - Control Station 5 - LKD & Fly Ash Longitudinal Strain 0.00005 0.00004 0.00003 0.00002 APLF minimum 40 micorstain Station 6 - Lime & Fly Ash 0.00001 0 0 850-0.00001 Time (10-2 sec)
Transverse Strain Data from Delaware County 12/06 45 mph 0.00009 0.00007 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 0.00005 0.00003 0.00001 APLF minimum 65 microstrain -0.00001 0 700-0.00003 Time (10-2 sec)
Total Deflections: Delaware County - 15 mph v 45 mph Station 5 (5% LKD with 5% Fly Ash) 0.006 0.005 APLF maximum 0.0039 in. 15 mph 45 mph 0.004 Deflection (in) 0.003 0.002 APLF minimum 0.0030 in. 0.001 0-5 15 35 55 75 95 115-0.001 Time (10-2 seconds)
Deflection of Unreclaimed Base: Delaware County Station 5 (5% LKD with 5% Fly Ash) 0.0045 0.004 0.0035 Deflection (in) 0.003 0.0025 0.002 0.0015 45 mph 15 mph 0.001 0.0005 0-10 10 30 50 70 90 110-0.0005 Time (10-2 seconds)
Pressure Cell Data from Delaware County 45 mph 35 30 25 Range of stresses from APLF St. 5-5% LKD & 5% Fly Ash St. 6-4% Lime & 6% Fly Ash Vertical Stress (kpa) 20 15 10 5 0 0 5 10 15 20 25 30 35 40 45-5 Time (10-2 sec)
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
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) 0.015 0.002 0.003 0.014 0.004 0.006 Barium 0.315 0.472 0.239 0.379 0.189 0.230 Calcium 728 443 1200 1410 1110 1170 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 0.126 0.156 0.123 0.127 Iron 0.259 0.216 0.112 BDL 0.186 0.175 Lead (Limit=5.0 mg/l) 0.028 0.045 ND ND ND ND Potassium ND ND ND ND ND ND Magnesium 40 532 20 BDL 40 50 Manganese ND ND 0.777 BDL 0.133 0.138 Mercury (Limit=0.2 mg/l) <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Molybdenum BDL BDL BDL 0.052 0.027 0.048 Nickel 0.026 BDL 0.045 BDL 0.025 0.035 Selenium (Limit=1.0 mg/l) 0.005 0.003 0.004 0.014 0.004 0.003 Silicon 4 ND 23 BDL 8 13 Sodium 18 20 11 30 66 17 Strontium 0.110 0.064 2.88 7.91 3.57 3.10 Sulfur 90 578 30 478 151 36 Zinc BDL BDL BDL BDL BDL BDL All values given in units of mg/l. BDL= Below Detection Limit Limits = Hazardous Waste Limit
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 0.002 <0.001 <0.001 Barium 0.168 0.281 0.028 0.095 Calcium 238 188 61 171 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) 0.032 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 1 0.4 4 1 Sodium 11 10 3 5 Strontium 0.051 0.025 0.189 0.373 Sulfur 1 1 10 4 Zinc 0.021 ND ND ND All values given in units of mg/l. BDL= Below Detection Limit Limits = Hazardous Waste Limit
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.
Field Sampling Results Site Samples Obtained Trips Warren Control 5 12 Warren CCP Section 1 12 Delaware #1 3 13 Delaware #2 0 7 Delaware #3 3 13 Delaware #4 2 13 Delaware #5 0 7 Delaware #6 0 13
Warren County Sampling Data Analyte EPA MCL CCP Section Control Aluminum - BDL 0.086 Arsenic 0.010 0.002 <0.001 Barium 2 0.079 0.056 Calcium - 935 915 Cadmium 0.005 BDL BDL Chromium 0.100 BDL BDL Copper 1.3 ND 0.051 Iron - 0.051 0.553 Lead 0.015 BDL BDL Potassium - 23 2 Magnesium - 22 12 Manganese - BDL BDL Mercury 0.002 <0.001 <0.001 Molybdenum - ND ND Nickel - BDL 0.025 Selenium 0.050 BDL <0.001 Silicon - 3 2 Sodium - 60 211 Strontium - 0.312 0.308 Sulfur - 913 765 Zinc - 0.087 0.047 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
Delaware County Sampling Data Analyte EPA MCL Section 1 Section 2 Section 3 Section 4 Section 5 Section 6 Aluminum - 0.952 - BDL 0.025 - - Arsenic 0.010 0.020-0.003 <0.001 0.002 0.003 Barium 2 0.051-0.538 0.027 - - Calcium - 145 - BDL 44 - - Cadmium 0.005 BDL - BDL BDL - - Chromium 0.100 0.020 - BDL BDL - - Copper 1.3 0.169-0.071 0.027 - - Iron - 0.320-0.223 0.172 - - Lead 0.015 BDL - BDL BDL - - Potassium - 79-42 - - - Magnesium - 22-97 4 - - Manganese - BDL - 0.160 BDL - - Mercury 0.002 <0.001 - <0.001 <0.001 - - Molybdenum - ND - ND ND - - Nickel - 0.274-0.058 0.020 - - Selenium 0.050 0.001-0.002 <0.001 <0.001 <0.001 Silicon - 11-6 1 - - Sodium - 312-334 121 - - Strontium - 1.10-1.31 0.103 - - Sulfur - 97-509 18 - - Zinc - 0.129-0.120 0.081 - - 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
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 2.83 5.67 4.18 2.87 5.71 4.19 2.86 5.81 4.21 ph finish 6.5 12.82 12.232 6.36 12.41 11.899 6.34 12.19 11.532 Al 0.034 0.70 0.48 0.036 2.40 2.8 0.049 2.7 4.2 As <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 1.5 B 0.15 0.03 <0.02 0.15 0.04 <0.02 0.34 0.04 0.10 Ba 0.39 0.21 0.12 0.26 0.10 0.07 0.27 0.11 0.02 60 Ca 2002 303 391 2239 155 166 2234 158 59 Cd <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 0.15 Cr <0.005 <0.005 0.067 0.007 <0.001 0.007 <0.005 <0.005 0.006 3 Cu 0.02 <0.001 <0.001 0.01 <0.001 <0.001 0.01 <0.001 <0.001 Fe 0.02 0.02 0.02 0.01 0.01 0.06 0.02 0.01 0.05 Hg <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 K 14.9 9.6 13.6 19.6 11.9 12.6 27.5 14.4 7.9 Mg 152 0.285 0.005 33.6 0.312 0.014 36.0 0.251 0.051 Mn 1.051 <0.001 <0.001 0.500 <0.001 <0.001 0.724 <0.001 <0.001 Mo 0.009 0.007 0.003 0.008 0.006 0.007 0.012 0.008 0.007 Na 11.5 5.6 4.7 11.0 4.6 3.5 14.4 5.6 3.0 Ni 0.11 0.013 <0.01 0.095 0.005 <0.01 0.098 0.006 <0.01 Pb 0.013 <0.006 <0.01 0.010 <0.006 <0.01 <0.006 <0.006 <0.01 S 32.5 4.9 7.1 19.7 6.6 7.5 22.9 6.0 8.8 Se <0.001 <0.001 <0.002 <0.001 <0.001 <0.002 <0.001 0.001 <0.002 1 Si 38.7 1.0 0.53 38.6 3.2 2.7 35.4 3.2 5.0 Sr 1.6 0.59 1.8 1.5 0.55 1.2 1.5 0.53 0.45 Zn 0.256 <0.005 0.01 0.344 0.003 <0.005 0.219 <0.005 <0.005 Unit: mg/l
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)
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
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.
Continuing Efforts Ongoing pavement performance and environmental condition measurements obtained from long-term monitoring and testing. Analytical studies, numerical modeling.
Structural Layer Coefficients Delaware County - Section Line Rd. Section 1 2 3 4 5 6 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 07/06 0.09763 0.08142 0.12738 0.10904 0.09382 0.11761 10172.5 5900 22597.5 14174.4 9029.17 17785 Before FDR 0.02085-0.0381 0.10716 0.05672 0.00796 0.08126 10/06 0.32171 0.4104 0.28455 0.17766 0.35223 0.26575 364033 755692 251896 61305.8 477772 205180 3 Weeks 0.40772 0.48671 0.3679 0.21509 0.43713 0.34572 04/07 0.29358 0.42144 0.29166 0.1492 0.35201 0.30227 276630 818369 271244 36309.2 476889 301933 7 months 0.37803 0.49532 0.37591 0.15844 0.43693 0.3875 07/07 0.25824 0.43855 0.28283 0.10187 0.42001 0.41259 188288 922125 247354 11559 810037 767857.3 10 months 0.33643 0.50823 0.36594 0.03467 0.49422 0.48843 10/07 0.32496 0.4328 0.34765 0.17519 0.44272 0.47269 375183 886315 459375 58784.7 948722 1154670 13 months 0.41099 0.50395 0.43288 0.21055 0.51131 0.53255 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 07/06 0.08783 0.06587 M R (psi) a 7408.3 3124 i Before FDR -0.0134-0.1068 Reults from AASHTO 09/06 0.07687 0.35631 MODCOMP5 Huang 4965.83 494545 3 Weeks -0.0567 0.44086 11/06 0.13008 0.40836 AASHTO: a i = 0.14*(M R /30,000) 1/3 24062.5 744513 3 months 0.11395 0.4851 04/07 0.11522 0.27351 Huang: a i = 0.29(log M R ) - 0.977 16724.7 223695 8 months 0.07462 0.35506 07/07 0.07615 0.37227 4827.33 564059 11 months -0.0598 0.45508 10/07 0.08335 0.54218 6331.06 1742470 14 months -0.0304 0.57705
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
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