Evaluation of Subbase using the Superpave Gyratory Compactor Mike Panko Kevin McGarvey Casey Hurt Cameron Corini Gregg Stevenson Dr. Beena Sukumaran Dr

Evaluation of Subbase using the Superpave Gyratory Compactor

Mike PankoKevin McGarveyCasey HurtCameron CoriniGregg StevensonDr. Beena SukumaranDr. Yusuf Mehta

Sukumaran et al. FAA Tech Transfer Conference, April 21, 2010

Background• Continuous loading from

airplane wheels create ruts in pavement

• Bigger and heavier planes with complex gear configurations make rut prevention more difficult

• FAA believes rutting is caused by densification of subbase


NAPTF – Rutting Behavior

North wheel track of CC3 flexible pavements at 19,500 passes

Picture courtesy of NAPTF


Field Compaction

-60

-55

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

-30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30

Offset from Centerline, feet

Ele

vati

on f

rom

Ref

eren

ce L

ine,

inch

es

LOW-STRENGTHSUBGRADE

SIX-WHEELTRAFFIC PATH

FOUR-WHEELTRAFFIC PATH

PA

VE

ME

NT

CE

NT

ER

LIN

E

P-401 AC SURFACE

P-209 BASE

P-154 SUBBASE

Interface profile measurements in the LFC2 posttraffic trench Courtesy of Garg and Hayhoe


• Background and Objectives

• Results from testing on P-154

• DGA Field to lab Comparison

• Conclusions

• Future Work

Outline


Research Approach

70

75

80

85

90

95

100

0 5 10 15 20No. of Passes

% M

od

ifie

d

Pro

cto

r

Field Data Lift# 1

Field Data Lift# 2

Field Data Lift# 4

Field Data Lift# 5

SGC

Nuclear Density Gauge

Field Compaction

100

105

110

115

120

125

130

135

0 10 20 30 40 50

No. of Gyration

Dry

Den

sity

(p

cf)

0 2 4 6 8 10 12

No. of Passes

Gyratory Compactor 03.17.08 Test#5

Lift # 3

Compare Compaction

CurvesSukumaran et al. FAA Tech Transfer Conference, April 21,

2010

Variables•Angle•Pressure•# of Gyrations

Gyratory Compactor


Shearing Action


• Angle Used: 1.25°

• Pressure Used: 600, 800, 1000 kPa

• # of Gyrations: 400 Gyrations

• Water Content Ranges:1-2%, 2-3%, 3-4%, 4-5%, 5-6%

•Sample Size: 3000 grams

Gyratory Compactor and Soil Parameters


P-154


• Determined OMC using Modified Proctor

• Compared SuperPave Gyratory Compactor Results to Modified Proctor

• Determined Compaction Energy using a Pressure Distribution Analyzer

P-154 Results


Compaction Properties of P-154


Comparison of SGC and Construction Compaction


MDD Placement in P-154


P-154 Comparison of Field and SGC Compaction


Compaction Energy


Shear Work

Ah

Pew

4


Vertical Work

hPAwv

wv = vertical work (in-lb)

P = Pressure (600 kPa ~ 87 psi)

A = Cross Sectional Area (28.27 in2)

∆h = change in height of sample (in)


Compaction Energy per Gyration


DGA


Compaction Properties of DGA


MDD Placement in DGA


DGA Comparison of Field and SGC Compaction


Comparison of Energy per Gyration


SGC vs. Proctor Tests

• Energy input from Proctor tests come from impact hammer.

• The SGC can achieve higher densities than the impact hammer alone.

• The energy input from the SGC comes from the vertical load applied, and the shearing caused by the gyratory movement, resulting in a higher energy.


Conclusions

• The SGC looks promising in evaluating compaction characteristics of unbound material during construction.

• The results from the SGC appear comparable to the deflection in the field for P-154 and DGA but needs further evaluation.


Future Work

Continue SGC testing at different moisture contents.

Obtain better field data for P-154, DGA and P-209 for comparison with SGC tests.

Compare SGC compaction energy to field compaction energy.


Acknowledgements

• FAA Grant #05-G-016• Dr. Gordon Hayhoe, FAA• Several FAA personnel for materials and

assistance with the database• SRA International personnel for data access

and assistance with the database


Questions ?

Date Test GyrationsPressure

(kPa)

% WaterAdded

byweight

MoistureContent% (Top)

Moisture Content %

(Bottom)

Avg. Moisture

(%)

MoistureDifference

(%)

2/1/2008 1 400 1000 6.0 5.462 5.941 5.70 8.40

2/1/2008 2 400 1000 6.0 5.446 5.969 5.71 9.16

2/1/2008 3 400 1000 6.0 5.173 6.011 5.59 14.97

2/1/2008 4 400 1000 6.0 5.507 5.905 5.71 6.97

2/26/2008 3 500 1000 6.0 5.183 6.090 5.64 16.09

2/26/2008 4 500 1000 6.0 5.167 6.041 5.60 15.58

2/28/2008 1 500 1000 5.0 3.989 4.241 4.11 6.11

2/28/2008 2 500 1000 5.0 4.177 4.388 4.28 4.93

2/29/2008 1 500 1000 5.0 4.093 4.368 4.23 6.50

2/29/2008 2 500 1000 5.0 4.351 4.603 4.48 5.63

2/29/2008 3 500 1000 5.0 4.485 4.630 4.56 3.20

Comparison of Water Content at Top and Bottom of Sample

Documents

Evaluation of Subbase using the Superpave Gyratory Compactor Mike Panko Kevin McGarvey Casey Hurt Cameron Corini Gregg Stevenson Dr. Beena Sukumaran Dr