MATERIALS•Surfacing Standards Surfacing Standards •Soil and Aggregate PropertiesSoil and Aggregate Properties•Aggregate DesignAggregate Design•Soil StabilizationSoil Stabilization•CompactionCompaction•Quality Control/Sampling and TestingQuality Control/Sampling and Testing•Quarry Development and ReclamationQuarry Development and Reclamation

Babeldoab Island, PalauHydrated tubular halloysite soilBob Gavenda NRCS

Dust and Palliatives

D. Elton

STABILIZERS AND DUST STABILIZERS AND DUST SUPPRESSANTSSUPPRESSANTS

• Cement, Lime, Fly Ash, Asphalt, Cement, Lime, Fly Ash, Asphalt, WaterWater

• Moisture Absorbing Products (Hygroscopic materials):Moisture Absorbing Products (Hygroscopic materials): Calcium chlorideCalcium chloride Magnesium chlorideMagnesium chloride Sodium chlorideSodium chloride

• Organic Petroleum Products:Organic Petroleum Products: Asphalt emulsionsAsphalt emulsions Liquid asphaltLiquid asphalt Dust oilsDust oils Modified asphalt emulsionModified asphalt emulsion

• Organic Non-Petroleum Products:Organic Non-Petroleum Products: LignosulfonatesLignosulfonates Animal FatsAnimal Fats Tree Resins, MolassesTree Resins, Molasses Tall Oils, Vegetable OilsTall Oils, Vegetable Oils

• Enzymes, Synthetic Polymers, Clay AdditivesEnzymes, Synthetic Polymers, Clay Additives

Surfacing Alternatives

Aggregate Use and Requirements

Aggregate Surface Design (30 mm, high quality)

0

100

200

300

400

500

600

700

0 10000 20000 30000 40000 50000 60000

Traffic, 18-kip ESALs

Aggr

egat

e Th

ickn

ess,

mm

CBR - 3CBR - 5CBR - 8CBR - 12

Aggregate Surface Design for 30mm Minus Aggregate of High Quality

Quality Control

DCP

You Get What You Inspect, Not What You Expect

Compaction

Drainage

Separation/Reinforcement

Unpaved Road DesignUnpaved Road Design00

2020

4040

6060

8080

100100

120120

00

0.50.5

1.01.0

1.51.5

2.02.0

2.52.5

3.03.0

3.53.5

4.04.0

0011

223344

55667788

9910101111

12121313

CO

NE

IND

EXC

ON

E IN

DEX

CB

RC

BR

SHEA

R S

TREN

GTH

, PSI

(C)

SHEA

R S

TREN

GTH

, PSI

(C)

Relationship between shear strength, CBR, & cone indexRelationship between shear strength, CBR, & cone index

C = 4.8 PSIC = 4.8 PSIFOR CBR = 1FOR CBR = 1

BearingCapacityFactors

Unreinforced:

With Geotextile:

With Geogrid/Geotextile: Typically CBR < 4

NNCC = 2.8 = 2.8

NNCC = 5.0 = 5.0

NNCC = 5.7 = 5.7

With Geogrid: (CBR > 4)

NNCC = 5.7 = 5.7

24 “

15 “13 “

WITHOUT GEOTEXTILE

WITH GEOTEXTILE

WITH GEOGRID/GEOTEXTILE

Unpaved Road DesignUnpaved Road Design

Materials RemovalBlack Cotton Soil

Materials Improvement

Grid RollerGrid Roller

Roadside Borrow Areas

Quarry Developmentand Reclamation

What is Important?What is Important?• Know your Soils and Traffic• Select the Appropriate Surfacing Standard• Use Appropriate Aggregate Gradation• Consider In-place Soil Stabilization• Use Cost-Effective Local Materials• Use Adequate Q C /Sampling & Testing • Compact your Soils and Aggregates• Drain your Materials• Develop Quarries…then Reclaim Them