With Application to Rural Roads in

Michigan

Presenter: Michael Duell P.E.

With Permission from: M.I. Pinard,

AFCAP

Background

DCP Design Method

Material Selection and Specification

Compaction Quality Control Using the DCP

Strengths and Limitations of DCP Design Method

Additional Sources of Information:

ASTM D 6951, User Guide to the Dynamic Cone

Penetrometer (MnDOT), Saskatchewan Highways and

Transportation-STP 240-20, AASHTO Interim Structural

Pavement Design Procedure, Chapter 5-Geotechnical Inputs

for Pavement & Design-FHWA, NHI-05-037.

Details Worth Sweating

• Soil investigationo Appropriate number and type of borings

o Verify limits of existing poor soil

o Include appropriate pay items for soil removal

o (i.e. subgrade undercutting, earth excavation, etc.)

o Include boring logs on either the plans or in the GI submittal documents

o DO NOT include the geotechnical report

•Pavement cores?o Good idea!o Should extend at least 1-inch beyond the proposed removal/

replacement thicknesso Example-project proposing milling 4” of existing 5” HMA depth, actual

depth was less than 4”

Backgroundo Increasingly difficult to maintain:

Constraints: Financial, logistical, and technical burden coupled with depletion of non-renewable resource (gravel)

Consequences: Lack reliable access to many rural communities

1 Mile= 1.61 Kilometers

o Solution: Upgrade unpaved roads to a paved standardo Problem: Cost of upgrading following traditional approaches is prohibitively

expensiveo Way forward: Research has led to development of new approach for

upgrading gravel roads to a paved standard based on the use of the Dynamic Cone Penetrometer (DCP)

1 Inch= 25.4 mm

1 Pound= 0.454 kg

1 INCH= 25.4 mm

E 80 x 106 kN= 18,000 x LBS (Single) AXLE LOAD)103

)

1 Mile = 1.61 Kilometers

(Low Volume Sealed Roads) pavement.

*= AASTO T180 (Modified Proctor)

*

Conclusions

The DCP-DN Design Method:Makes use of a relatively inexpensive, multi-purpose device for characterizing

existing gravel road, testing pavement materials and undertaking compaction quality control.

Is based on a relatively simple design procedure that produces cost-effective environmentally optimized designs

Allows more extensive use to be made of local materials

Offers potential for economically upgrading a significantly greater length of gravel roads to a paved standard with similar risk as conventional pavement design techniques

Need for full appreciation of the strengths and weaknesses of the DCP device

Conclusions

Chip Seal Road10 Years After Construction

Gravel Road 4 Years After Construction

1 Mile = 1.61 Kilometers

Correlation of Data

log CBR = 2.46-1.12 log DPI

Where DPI = mm/Blow

MnDot 2502 Acceptance Specification of Pavement Edge

Drain Backfill Material

Locating Layers in Pavement Structures and Pavement

Rehabilitation Strategy Determination

Supplementing Foundation Testing for Design

Identifying Weak Spots in Constructed Embankments

Locating Boundaries of Required Subcuts

Determining Thaw/Freeze Depth During Spring

MnDOT

Pavement Design AASHTO ‘93 MOD. Crush & Shape Given: Reg. Factor = 4.5 Terminal Serv. =4.5 SSV=3.0SN =4.63 ESAL=1,000,000 ADT =320 DES. Life =20yrs Comm. ADT =2% MR (psi) =30,000 (ai /0.14)3

MR (psi) =2555 (CBR)0.64 CBR =292/( DCP1.12 ) mm/Blow

Auger Sample

Pvmnt Des.ai

MR PSi CBR %

IN/Blow

1.5 HMA1.5 HMA2.5 Recycle

0.420.420.20

9” AGG Base

8” AGG Base 0.14 30,000 46.9 0.20

24”Sand

12” SandSubbase

0.10 10,900 9.7 0.83

13”Sand SubgradeSSV = 3 CBR 3.5

0.08 5,700 3.5 2.86

SN = 5.12 › 4.63

0

9

33

0” 1” 2” 3”

Required LSP

Questions?