Shongtao Dai, Ph.D, PEShongtao Dai, Ph.D, PE

Office of MaterialsOffice of Materials

Minnesota Department of TransportationMinnesota Department of Transportation

6/24/086/24/08

Kevin ErbKevin Erb

University of Wisconsin ExtensionUniversity of Wisconsin Extension

9/22/089/22/08Mn/DOT

Office of Materials and Road Research

Effects of Implements of Husbandry “Farm Equipment”

on Pavement Performance

Mid 2008 Summary

Background

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

Minnesota County Highway Engineers.Minnesota County Highway Engineers.

Background

Determined early on that this is an Determined early on that this is an issue bigger than just Wisconsinissue bigger than just Wisconsin Contacted DOT in 8 states.Contacted DOT in 8 states. Examined existing testing facilities Examined existing testing facilities Chose to partner with Minnesota DOTChose to partner with Minnesota DOT

Existing research facility (MnROAD) Existing research facility (MnROAD) Similar needs identifiedSimilar needs identified

Background

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

Background

Industry PartnershipIndustry Partnership Manure Applicator Associations (WI, MN, IA, OH, Manure Applicator Associations (WI, MN, IA, OH,

PA, MI)PA, MI)

Farm equipment manufacturersFarm equipment manufacturers

Major Objectives

Determine pavement responses to Determine pavement responses to selected agricultural equipment using selected agricultural equipment using instrumented pavements.instrumented pavements.

Compare pavement response to typical Compare pavement response to typical 5-axle semi (80,000 lbs).5-axle semi (80,000 lbs).

Research Approach

Construct two asphalt test sections that Construct two asphalt test sections that represent typical local roadsrepresent typical local roads

Utilize existing concrete pavement test Utilize existing concrete pavement test sections at test facility (MnROAD)sections at test facility (MnROAD)

Visually assess gravel roadVisually assess gravel road

What is MnROAD? Very comprehensive Very comprehensive

pavement research facilitypavement research facility.. Constructed in 1994 and located Constructed in 1994 and located

about 40 miles NW of the Twin about 40 miles NW of the Twin Cities.Cities.

Mainline and Low Volume Road.Mainline and Low Volume Road. Originally more than 4500 Originally more than 4500

sensors embedded within 40 sensors embedded within 40 sections:sections:

Strain gauges, LVDTs, TDRs, Strain gauges, LVDTs, TDRs, Thermocouples, pressure cells.Thermocouples, pressure cells.

http://www.dot.state.mn.us/mnroad/index.html

Research Approach Construct two asphalt test sections on Construct two asphalt test sections on

MnROAD research facility (A & B)MnROAD research facility (A & B)

BA

Cell 84 (Thick)Cell 84 (Thick) 5.5” HMA with PG58-34 5.5” HMA with PG58-34 9” gravel aggregate base9” gravel aggregate base A-4 subgrade soil (existing A-4 subgrade soil (existing

subgrade soil).subgrade soil).

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

soil).soil).

5.5” HMA

8in. Aggregate base

A6 clay subgrade

3.5” HMA

8” Aggregate base

A6 clay subgrade

9” Aggregate base

Research Approach

Utilize existing concrete pavement test Utilize existing concrete pavement test sections at test facilitysections at test facility

Existing PCC sections on MnROADExisting PCC sections on MnROAD Cell 32Cell 32

5” PCC5” PCC 6” Aggregate base6” Aggregate base

5” PCC

6” Aggregate base

A6 clay subgrade

Cell 54Cell 54 7.5” PCC7.5” PCC 12” Aggregate base12” Aggregate base

7.5” PCC

12” Aggregate base

A6 clay subgrade

Research Approach

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

Research Approach Strain Gauges: measures strain to surface layer Strain Gauges: measures strain to surface layer

(asphalt or concrete) – at bottom of layer, edge of road(asphalt or concrete) – at bottom of layer, edge of road

Deflection gauges (LVDT): deformation of pavement Deflection gauges (LVDT): deformation of pavement sections/segmentssections/segments

Contact Pressure (surface): tire-pavement foot print Contact Pressure (surface): tire-pavement foot print and pressure distributionand pressure distribution

Temperature/moistureTemperature/moisture

Instrumentation of Test SectionsInstrumentation of Test Sections Strain gauges: bottom of HMA (18 per Strain gauges: bottom of HMA (18 per

section)section) Pressure in base (6 per section)Pressure in base (6 per section) LVDTs (3 per section)LVDTs (3 per section) Base moisture measurement: TDR & ECH20 Base moisture measurement: TDR & ECH20

(8 per section)(8 per section) Thermocouples (32 in cell 83; 16 in cell 84)Thermocouples (32 in cell 83; 16 in cell 84)

Contact pressure gauge (Tekscan)Contact pressure gauge (Tekscan)

Project Status Spring – April 2007Spring – April 2007

Developed workplanDeveloped workplan Select test equipmentSelect test equipment

Construction done Oct. 2007Construction done Oct. 2007

Trial Test – Dec. 2007Trial Test – Dec. 2007

Project Status 11stst Spring test – Between Spring test – Between

Mar 17 & 27, 2008 (Spring Mar 17 & 27, 2008 (Spring thaw period) thaw period) Manure trucks, tires, sprayersManure trucks, tires, sprayers

11stst Fall test: Aug 25-Sept 5 Fall test: Aug 25-Sept 5 (dry fall)(dry fall) Large tankers, flotation tiresLarge tankers, flotation tires

3 year project3 year project 2 weeks in spring2 weeks in spring 2 weeks in fall2 weeks in fall

Yellow are Spring 2008 tested. Pink are Fall 2008 tested equipment

S1: 4400 gal

S3: 1800 gal

S2: 4400 gal

T2: 4000 galT1: 6000 gal

T3: 6000 gal

7300 gal9500 gal

6000 gal

Test Configuration 4 different weight: 0%; 25%; 50%; 80% full*4 different weight: 0%; 25%; 50%; 80% full*

These 4 percentages allow us to determine the effects of These 4 percentages allow us to determine the effects of different types of manure and different tank sizes.different types of manure and different tank sizes.

3 different speed: Static; 5 mph; 10 mph3 different speed: Static; 5 mph; 10 mph

Offset from pavement edge: 0 & 12 inchesOffset from pavement edge: 0 & 12 inches

Test Results

Our goal is to have a wet/dry fall and Our goal is to have a wet/dry fall and wet/dry early spring test.wet/dry early spring test.

Full data will be available when Full data will be available when completedcompleted

Test Results

Preliminary DataPreliminary Data Tire designs have an impact (brighter color – more Tire designs have an impact (brighter color – more

pressure on pavement) 6,000 gal tanker @ 80%pressure on pavement) 6,000 gal tanker @ 80%

80% full0% full

Test Results

Preliminary DataPreliminary Data Fall: 7500 gal tanker (0%, 80% full), 80,000 lb semiFall: 7500 gal tanker (0%, 80% full), 80,000 lb semi Each colored square is 0.7 inches by 0.7 inchesEach colored square is 0.7 inches by 0.7 inches

80,000 lb

Semi

0% full 80% full

Pavement Performance (Rutting)Pavement Performance (Rutting)

Cell 83 (11/2/07, 3/20/08. 3/26/08)(Westbound, Outside wheelpath)

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

100020 100070 100120 100170 100220 100270 100320

Station

Ru

t (i

n)

After week 2 (3/26/08)

After week 1 (3/20/08)

Post-construction (11/2/07)

Test Results

Preliminary presentation of 1Preliminary presentation of 1stst year year data: January, 2009data: January, 2009

Full data will be available when Full data will be available when completedcompleted

Thank you