2010 FAA Airport Technology Transfer Conference Some Key Findings from NAPTF Testing of Unbonded PCC Overlays IPRF Project 04-02: Improved Overlay Design Parameters for Concrete Airfield Pavements —The Baseline Experiment IPRF Project 06-03: Evaluation of Design Parameters for Rigid Overlays —SCI Validation Study

2010 FAA Airport Technology Transfer Conference Overview

2010 FAA Airport Technology Transfer Conference 6 inch OL 10 inch SL 7.5 inch OL 7.5 inch UL High-strength SubgradeLow-strength Subgrade 9 inch OL 6 inch UL Medium-strength Subgrade Baseline Experiment—2006 (2007) 9 inch OL 6 inch OL 10 inch SL 7.5 inch OL 7.5 inch SL High-strength SubgradeLow-strength Subgrade 6 inch SL Medium-strength Subgrade SCI Validation Study—2007/2008 (2009) Full-Scale Testing at the NAPTF

2010 FAA Airport Technology Transfer Conference Longitudinal and Transverse Cross-Sections NORTHSOUTH

2010 FAA Airport Technology Transfer Conference Date Passes SCI 08/01/ /03/ /10/ /11/ /24/ /28/ /13/ /14/ /19/ /22/ /04/ /29/ /02/ /03/ Triple Dual Tandem 57 in 54 in 50,000 lbs/wheel 230 psi tire pressure Test Item N Final Passes OL SCI UL SCI 8.6-in PCC OL 6.3-in PCC UL 5.6-in Aggregate Base Subgrade k=135 pci UL SCI = 100

2010 FAA Airport Technology Transfer Conference Dual Tandem 57 in 54 in 50,000 lbs/wheel 230 psi tire pressure Test Item S1 08/04/ /08/ /10/ /09/ /11/ /13/ /22/ /26/ /02/ /03/ /14/ /29/ /31/ /19/ Date Passes SCI 8.7-in PCC OL 6.3-in PCC UL 5.8-in Aggregate Base Subgrade k=135 pci Final Passes OL SCI UL SCI UL SCI = 100

2010 FAA Airport Technology Transfer Conference 12/18/06 Structural Section 1 02/20/07 Transition 1N-7U 1N-8U 1N-9U 1N-10U 1N-11U 1N-12U 1N-1U 1N-2U 1N-3U 1N-4U 1N-5U 1N-6U 1S-7U 1S-8U 1S-9U 1S-10U 1S-11U 1S-12U 1S-1U 1S-2U 1S-3U 1S-4U 1S-5U 1S-6U

2010 FAA Airport Technology Transfer Conference Test Item N1 Triple Dual Tandem 57 in 54 in 42.5k lbs/wheel 230 psi tire pressure 9.3-in PCC OL 6.3-in PCC UL 5.6-in Aggregate Base Subgrade k=135 pci 11/14/ /19/ /21/ /03/ /05/ /07/ /10/ /11/ /19/ /11/ /16/ /18/ Date Passes SCI Final3 UnderlaySCI Beginning25

2010 FAA Airport Technology Transfer Conference Dual Tandem 57 in 54 in 42.5k lbs/wheel 230 psi tire pressure Test Item S1 9.3-in PCC OL 6.3-in PCC UL 5.8-in Aggregate Base Subgrade k=135 pci 04/02/ Date Passes SCI 01/16/ /23/ /01/ /25/ /24/ /13/ /05/ /20/ /21/ /26/ /04/ /11/ UnderlaySCI Beginning23 Final8

2010 FAA Airport Technology Transfer Conference Selected Summary of Goals and Findings Measured Responses Gears Layer Interactions Performance SCI

2010 FAA Airport Technology Transfer Conference A. Refine the relationship between underlying pavement effective modulus and SCI SCI was calculated according to ASTM D 5340 “Standard Test Method for Airport Pavement Condition Index Survey.” The SCI value of a test item represents the crack types, crack density and crack severity that are distributed in the 12 slabs within a test item.

2010 FAA Airport Technology Transfer Conference Dr. Rollings’ Model Observation on 6 slabs on subgrade at WES. Cracks were introduced by dropping a headache ball. Initial slab moduli were determined by BISDEF from FWD results. Deteriorated slab moduli were determined by using BISAR to match the deflection under the center of the loaded plate. Subgrade was assigned a constant value = psi. SCI of slabs were calculated based on assumption that a single type of crack in one slab represents 50% of slabs within a test item having the same specific type of crack.

2010 FAA Airport Technology Transfer Conference Underlay SCI Investigation

2010 FAA Airport Technology Transfer Conference Comparison to Rollings Relationship

2010 FAA Airport Technology Transfer Conference

10 X 10 grid in 12.5 ft X 12.5 ft slab DateCrack Densitytotal crack length, ft# of pieces 8/8/200611/100 = 11% /10/200618/100 = 18% /22/200621/100 = 21% /26/200630/100 = 30% /29/200635/100 = 35%489 10/2/200643/100 = 43% Alternate Indicators of Structural Damage or Crack Density

2010 FAA Airport Technology Transfer Conference Relationship between Underlay E-Ratio and Distress Density Intervals

2010 FAA Airport Technology Transfer Conference Finding: Rollings equation using SCI provides a reasonable fit to BAKFAA moduli from HWD testing for the underlay. Recommendation: Continue use of the Rollings equation, with some modification.

2010 FAA Airport Technology Transfer Conference B. Improve understanding of how underlay condition affects overlay performance, and of the interaction between pavement layers. SCI Initial – Final (Passes) 50,000-lb wheel load 42,500-lb wheel load Test ItemBaseline OLBaseline ULSCI OLSCI UL N (5146) (15,510) N (5146) (35,260) N (5146) (35,260) S (12,142) (33,264) S (16,567) (42,834) S (12,142) (35,250)

2010 FAA Airport Technology Transfer Conference Baseline Experiment

2010 FAA Airport Technology Transfer Conference SCI Validation Study

2010 FAA Airport Technology Transfer Conference Baseline Experiment: Approximate Passes to SCI Values SCI Passes N1 9”/6” S1 9”/6” N2 7.5”/7.5” S2 7.5”/7.5” N3 6”/10” S3 6”/10”

2010 FAA Airport Technology Transfer Conference SCI Validation Study: Approximate Passes to SCI Values SCI Passes N1 9”/6” S1 9”/6” N2 7.5”/7.5” S2 7.5”/7.5” N3 6”/10” S3 6”/10” > ???

2010 FAA Airport Technology Transfer Conference Finding: Considering load effects only, unbonded overlays over existing pavements with lower SCI values accumulated more passes to failure than anticipated. Finding: Overlays of equal or less thickness to the existing pavement achieved the best performance, for the same overall total pavement thickness.

2010 FAA Airport Technology Transfer Conference Matched and Mismatched Transverse Joints Examined on the basis of: Overall performance Intact slab life Load transfer efficiency Deflection basin area Although matched and mismatched transverse joints exhibited slightly different mechanical behavior for the unbonded overlay, the passes prior to the first crack or to failure were affected more by other structure parameters such as E*h ratio.

2010 FAA Airport Technology Transfer Conference Intact Slab Life – Number of passes prior to the first crack of a slab normalized to number of passes prior to SCI = 80 of the test item North Test Item (Initial UL SCI)

2010 FAA Airport Technology Transfer Conference Intact Slab Life – Number of passes prior to the first crack of a slab normalized to number of passes prior to SCI = 80 of the test item South Test Item (Initial UL SCI)

2010 FAA Airport Technology Transfer Conference Recommendation: From this experiment, there was no evidence to indicate that joints should not be mismatched if there is a reason to do so. Other factors should govern this decision.

2010 FAA Airport Technology Transfer Conference C. Quantify differences in responses and resulting impacts on failure criteria between dual tandem and triple dual tandem gears. Passes to SCI Levels

2010 FAA Airport Technology Transfer Conference Total Gear Load on North Test Items = 150% of Total Gear Load on South Test Items Baseline SCI Section 1 Pass RatioSection 2 Pass RatioSection 3 Pass Ratio SCI Validation Ratios of Passes on Test Items (South/North)

2010 FAA Airport Technology Transfer Conference Predicted Ratios from FAARFIELD (South/North) Total Gear Load on North Test Items = 150% of Total Gear Load on South Test Items Baseline SCI Section 1 Pass RatioSection 2 Pass RatioSection 3 Pass Ratio SCI Validation

2010 FAA Airport Technology Transfer Conference

Strain Recovery % Between Axles Baseline Experiment Pre-Cracking Responses Strain Gage Location N1S1N2S2N3S3 MeanSDMeanSDMeanSDMeanSDMeanSDMeanSD Top of Overlay Bottom of Overlay Top of Underlay Bottom of Underlay

2010 FAA Airport Technology Transfer Conference D. Verify whether measured responses match predicted responses from current models and design methods. (Rollings, 1988)

2010 FAA Airport Technology Transfer Conference

(Rollings, 1988)

2010 FAA Airport Technology Transfer Conference BASELINE EXPERIMENT FAARFIELD ANALYSIS SUMMARY WITH MR = 550 psi TEST ITEMSN1S1N2S2N3S3 STRUCTURAL CROSS-SECTIONS 8.6-in OL 6.3-in UL 5.6-in Agg 8.7-in OL 6.3-in UL 5.8-in Agg 7.4-in OL 7.4-in UL 5.5-in Agg 7.3-in OL 7.7-in UL 5.7-in Agg 5.6-in OL 9.8-in UL 4.7-in Agg 5.7-in OL 9.8-in UL 4.8-in Agg INITIAL UNDERLAY SCI 100 MATERIAL INFORMATION E pcc = 4M psi, MR = 550 psi, k sub = 135 pci, %CDFU = 0% LOADING CONFIGURATION Dual Spacing: 54 in., Tandem Spacing: 57 in. Wheel Load: 50,000 lb., Tire Pressure: 230 psi TripleTwinTripleTwinTripleTwin PREDICTED STRESSES (psi) OVERLAY UNDERLAY

2010 FAA Airport Technology Transfer Conference SCI VALIDATION STUDY FAARFIELD ANALYSIS SUMMARY WITH MR = 550 psi TEST ITEMSN1S1N2S2N3S3 STRUCTURAL CROSS-SECTIONS 9.3-in OL 6.3-in UL 5.6-in Agg 9.4-in OL 6.3-in UL 5.8-in Agg 8.2-in OL 7.4-in UL 5.5-in Agg 8.2-in OL 7.7-in UL 5.7-in Agg 6.5-in OL 9.8-in UL 4.7-in Agg 6.5-in OL 9.8-in UL 4.8-in Agg INITIAL UNDERLAY SCI MATERIAL INFORMATION E pcc = 4M psi, MR= 550 psi, k sub = 135 pci, %CDFU= 100% LOADING CONFIGURATION Dual Spacing: 54 in., Tandem Spacing: 57 in. Wheel Load: 42,500 lb., Tire Pressure: 230 psi TripleTwinTripleTwinTripleTwin PREDICTED STRESSES (psi) OVERLAY UNDERLAY

2010 FAA Airport Technology Transfer Conference Baseline Test Item N1

2010 FAA Airport Technology Transfer Conference Baseline Test Item S1

2010 FAA Airport Technology Transfer Conference SCI Validation Test Item N1

2010 FAA Airport Technology Transfer Conference SCI Validation Test Item S1

2010 FAA Airport Technology Transfer Conference Data for Ongoing and Future Analysis

2010 FAA Airport Technology Transfer Conference CUMULATIVE AREA AND PEAK STRAIN FOR ODD-NUMBERED PASSES (WEST TO EAST) FOR EG-O-N1-1B

2010 FAA Airport Technology Transfer Conference CUMULATIVE AREA AND PEAK STRAIN FOR EVEN-NUMBERED PASSES (EAST TO WEST) FOR EG-O-N1-1B

2010 FAA Airport Technology Transfer Conference QES: Co-PI Dennis Morian, Joe Reiter, Suri Sadasivam,..... Penn State: Lin Yeh, Vishal Singh, Hao Yin, Maria Lopez de Murphy Other team members: Tasos Ioannides, Shie Shin Wu, John Rice Acknowledgements Jim Lafrenz Project Panel David Brill, Gordon Hayhoe, Murphy Flynn, Frank Pecht,..... Project Team Members

2010 FAA Airport Technology Transfer Conference THANK YOU QUESTIONS?