Shongtao Dai, Ph.D, PE

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Effects of Implements of Husbandry Farm
Equipment on Pavement PerformanceMid 2008
Summary

• Shongtao Dai, Ph.D, PE
• Office of Materials
• Minnesota Department of Transportation
• 6/24/08
• Kevin Erb
• University of Wisconsin Extension
• 9/22/08

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Background

• Study initiated by Professional Nutrient
  Applicators Association of Wisconsin (PNAAW) in
  consultation with the Wisconsin Towns
  Association.
• Several others with similar interest, including
  
• Minnesota County Highway Engineers.

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Background

• Determined early on that this is an issue bigger
  than just Wisconsin
• Contacted DOT in 8 states.
• Examined existing testing facilities
• Chose to partner with Minnesota DOT
• Existing research facility (MnROAD)
• Similar needs identified

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Background

• Created a multi state Pooled Fund Research Study
  (2007-2010)
• Allowed states and federal government to join
• project.
• Iowa, Minnesota, Illinois DOT, Mn Local Road
• Research Board (LRRB).
• Wisconsin DOT chose not to participate (yet)

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Background

• Industry Partnership
• Manure Applicator Associations (WI, MN, IA, OH,
• PA, MI)
• Farm equipment manufacturers

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Major Objectives

• Determine pavement responses to selected
  agricultural equipment using instrumented
  pavements.
• Compare pavement response to typical 5-axle semi
  (80,000 lbs).

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Research Approach

• Construct two asphalt test sections that
  represent typical local roads
• Utilize existing concrete pavement test sections
  at test facility (MnROAD)
• Visually assess gravel road

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What is MnROAD?

• Very comprehensive pavement research facility.
• Constructed in 1994 and located about 40 miles
  NW of the Twin Cities.
• Mainline and Low Volume Road.
• Originally more than 4500 sensors embedded within
  40 sections
• Strain gauges, LVDTs, TDRs, Thermocouples,
  pressure cells.

http//www.dot.state.mn.us/mnroad/index.html
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Research Approach

• Construct two asphalt test sections on MnROAD
  research facility (A B)

B
A
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• Cell 83 (Thin)
• 3.5 HMA with PG58-34
• 8 gravel aggregate base
• A-4 subgrade soil (existing subgrade soil).

• Cell 84 (Thick)
• 5.5 HMA with PG58-34
• 9 gravel aggregate base
• A-4 subgrade soil (existing subgrade soil).

3.5 HMA
5.5 HMA
8 Aggregate base
8in. Aggregate base
9 Aggregate base
A6 clay subgrade
A6 clay subgrade
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Research Approach

• Utilize existing concrete pavement test sections
  at test facility

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• Existing PCC sections on MnROAD
• Cell 32
• 5 PCC
• 6 Aggregate base

• Cell 54
• 7.5 PCC
• 12 Aggregate base

5 PCC
7.5 PCC
6 Aggregate base
12 Aggregate base
A6 clay subgrade
A6 clay subgrade
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Research Approach

• Build sensors into and below pavement to
  determine impact of farm equipment compared to an
  80,000 lb semi

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Research Approach

• Strain Gauges measures strain to surface layer
  (asphalt or concrete) at bottom of layer, edge
  of road
• Deflection gauges (LVDT) deformation of pavement
  sections/segments
• Contact Pressure (surface) tire-pavement foot
  print and pressure distribution
• Temperature/moisture

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• Instrumentation of Test Sections
• Strain gauges bottom of HMA (18 per section)
• Pressure in base (6 per section)
• LVDTs (3 per section)
• Base moisture measurement TDR ECH20 (8 per
  section)
• Thermocouples (32 in cell 83 16 in cell 84)

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• Contact pressure gauge (Tekscan)

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Project Status

• Spring April 2007
• Developed workplan
• Select test equipment
• Construction done Oct. 2007
• Trial Test Dec. 2007

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Project Status

• 1st Spring test Between Mar 17 27, 2008
  (Spring thaw period)
• Manure trucks, tires, sprayers
• 1st Fall test Aug 25-Sept 5 (dry fall)
• Large tankers, flotation tires
• 3 year project
• 2 weeks in spring
• 2 weeks in fall

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Yellow are Spring 2008 tested. Pink are Fall 2008
tested equipment
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S1 4400 gal
S2 4400 gal
S3 1800 gal
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T1 6000 gal
T2 4000 gal
T3 6000 gal
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9500 gal
7300 gal
6000 gal
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Test Configuration

• 4 different weight 0 25 50 80 full
• These 4 percentages allow us to determine the
  effects of different types of manure and
  different tank sizes.
• 3 different speed Static 5 mph 10 mph
• Offset from pavement edge 0 12 inches

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Test Results

• Our goal is to have a wet/dry fall and wet/dry
  early spring test.
• Full data will be available when completed

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Test Results

• Preliminary Data
• Tire designs have an impact (brighter color
  more pressure on pavement) 6,000 gal tanker _at_
  80

80 full
0 full
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Test Results

• Preliminary Data
• Fall 7500 gal tanker (0, 80 full), 80,000 lb
  semi
• Each colored square is 0.7 inches by 0.7 inches

80,000 lb Semi
0 full
80 full
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• Pavement Performance (Rutting)

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Test Results

• Preliminary presentation of 1st year data
  January, 2009
• Full data will be available when completed

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Thank you