designing pcc pavements for economy and longevity - American ...

DESIGNING PCC PAVEMENTS
FOR ECONOMY AND LONGEVITY
WOUTER GULDEN P.E.
DIR. OF ENGINEERING AND TRAINING
AMERICAN CONCRETE PAVEMENT ASSOCIATION,
SOUTHEAST CHAPTER
CONCRETE AIRPORT PAVEMENT WORKSHOP
NOVEMBER 4‐5, 2009 ATLANTA, GEORGIA

Economize Concrete Pavement?
Longitudinal joints
Transverse joints
Thickness Design
Concrete materials?
Shoulder
Subgrade
Subbase/Drains

Concrete Pavement Design
Geometrics
Thickness(es)
Joints
Materials

Concrete Pavement Design
Geometrics
`
Thickness
Joints
Materials
Most Often Influence Cost
& Selection of Projects
C
O
S
T

Concrete Pavement Design
Geometrics
Thickness
Joints
Materials
Most Often Influence
Real-world Performance
PERFORMANCE

Design Procedures for Roads
Empirical Design Procedures
Based on observed performance
AASHO Road Test
Mechanistic Design Procedures
Based on mathematically calculated pavement responses
PCA Design Procedure (PCAPAV)…….Revised as StreetPave
Mechanistic-Empirical Design
AASHTO MEPDG

Principles of Design
Load stresses
Thickness
Curling/Warping stresses
Volume change stresses
Jointing

Concrete Pavement Design
Load Transfer (slabs( ability to share its load with neighboring g slabs)
Dowels
L= x
U = 0
Aggregate Interlock
Poor Load Transfer
Edge Support
Widened lane
Tied concrete shoulder
L= x/2
Good Load Transfer
U= x/2

Aggregate Interlock
Shear between aggregate particles
below the initial saw cut

Edge Support
Concrete Shoulder Curb & Gutter Widened Lane
te separat
or
integral

AASHTO Pavement Design Guide
Empirical methodology based on
AASHO Road Test in the late
1950’s
Several versions:
1961 (Interim Guide), 1972, 1986,
1993
1986 Guide highlights the need for
mechanistic design
Design Guide

AASHO Road Test
(1958-1960)
Third large scale road test
1 st : Maryland Road Test (1950-51)
Rigid pavements Only
2 nd : WASHO Road Test (1952-54)
Flexible pavements only
Included both rigid and flexible
pavement test sections
Included a wide range of axle
loads and pavement cross-
sections

1986-93 Rigid Pavement Design
Equation
Standard
Normal Deviate
Overall
Standard Deviation
Depth
Log(ESALs) =
Z * s + 735 7.35 * Log(D + 1) - 006 0.06 +
R
Terminal
Serviceability
( )
o
Modulus of
Rupture
Drainage
Coefficient
i
⎢ S' * C *
[
D 0.75 − 1.132
]
422 - * c d
+ 4.22 0.32p
t
Log
⎡
⎢
⎢
⎢
⎡
215.63 * J * D
0.75
⎢ -
⎢
⎣
⎣⎢
Load
Transfer
E / k
Load ( c
)
Modulus
of Elasticity
Change in Serviceability
⎡
⎡ Δ PSI
⎢ Log
⎢
⎢ ⎣ 4.5 - 1.5
⎢ 1.624 * 10
⎢ 1+
⎣⎢
18.42
(
D +
)
⎤
⎥
⎥
⎥
⎥
⎥
1 846 .
⎤
⎥
⎦
⎤
⎥
025 .
⎦⎥
⎦
Modulus of
Subgrade Reaction
7
⎤
⎥
⎥
⎥
⎥
⎦⎥

1986-93 Rigid Pavement Design
Rigid pavement design parameters
Thickness
Serviceability (p o , p t )
Traffic (ESALs, E-18s)
Load transfer (J)
Concrete properties (S’ c , E c )
Subgrade strength (k, LS)
Drainage (C d )
Reliability (R, S o )

Traffic Characterization
Equivalent Number of 18k Single Axle Loads

AASHTO Design – Traffic
Load Equivalency Factor (LEF)
The ratio of the effect (damage) of a specific axle load on
pavement serviceability to the effect produced by an 18-kip
axle load at the AASHO Road Test
Change for each:
Pavement Type
Thickness
Terminal Serviceability.

AASHTO Design - Traffic
ESAL’s or E-18’s
The number and weight of all axle loads from the
anticipated vehicles expected during the pavement
design life - expressed in 18-kip (80 kN) Equivalent
Single Axle Loads for each type of pavement.
—Rigid ESAL’s or E-18’s
—Flexible ESAL’s or E-18’s

18 kip ESALs
VEHICLE
NUMBER
RIGID
ESALs
FLEXIBLE
ESALs
Single Units 2 Axle 20 6.38 6.11
Busses 5 13.55 8.73
Panel Trucks 10 10.89 11.11
Semi-tractor Trailer 3 Axles 10 20.06 13.41
Semi-tractor Trailer 4 Axles 15 39.43 29.88
Semi-tractor Trailer 5 Axles 15 57.33 36.87
Automobile, Pickup, Van 425 1.88 2.25
Total 500 149.52 108.36

StreetPavetP
Pavement Design
Procedure
.

StreetPave Design Procedure
ACPA Design Procedure
used in StreetPave
A pavement design tool for
low volume roads (streets &
local roads
Based on the PCA’s
pavement thickness design
methodology
PCA assesses adequacy of
concrete thickness using both
fatigue and erosion criteria

Fatigue Analysis
Allowable number of
load repetitions for
each axle group is
determined
% Fatigue is
calculated for each
axle group
Total fatigue
consumed should
not exceed 100%.
Critical Loading Position
Fatigue
Transverse joint
Midslab loading away from
transverse joint produces critical
edge stresses

Erosion Analysis
Repetitions of heavy axle
loads cause:
pumping; erosion of
subgrade, subbase and
shoulder materials; voids
under and adjacent to the
slab; and faulting of
pavement joints.
A thin pavement with its
shorter deflection basin
receives a faster load
punch than a thicker slab.
Critical Loading Position
Erosion
Corner loading produces critical
pavement deflections
Transverse joint

Project Specific “Global” Inputs in
StreetPave
Project information.
Design life.
Reliability*
.
Failure criteria*.
Terminal serviceability.
Percent cracked slabs.
*These values should be selected based on policy
and experience.

Reliability
Levels of Reliability for Pavement Design
Functional Classification of
Roadway
Interstates, Freeways, and
Tollways
Recommended d Reliability
Urban
Rural
85 - 99 80 – 99
Principal Arterials 80 - 99 75 – 95
Collectors 80 - 95 75 – 95
Residential & Local Roads 50 - 80 50 – 80

Failure Criteria (Cracked Slabs)
Recommended Levels of Slab Cracking by Roadway Type
Roadway Type
Recommended Percent of
Slabs Cracked at End of
Design Life
(Default) 15%
Interstate Highways, Expressways,
Tollways, Turnpikes
5%
State Roads, Arterials 10%
Collectors, County Roads 15%
Residential Streets 25%

Combined Effects of Reliability and
Failure Criteria

Site Condition Inputs in StreetPave
The following StreetPave input data is needed for
a specific project.
Traffic category.
Ttl Total number of lanes.
Directional distribution.
Design lane distribution.
ib ti
ADTT or ADT plus % trucks.
Truck traffic growth.
Subgrade support value (k).

Street Classifications
Street Class Description
Two-way Average
Daily Traffic
(ADT)
Two-way Average
Daily Truck Traffic
(ADTT)
Typical Range of
Slab Thickness
Light
Residential
Residential
Collector
Business
Industrial
Short streets in subdivisions and similar
residential areas – often not through-streets.
Through-streets in subdivisions and similar
residential areas that t occasionally carry a
heavy vehicle (truck or bus).
Streets that collect traffic from several
residential subdivisions, and that may serve
buses and trucks.
Streets that provide access to shopping and
urban central business districts.
Streets that provide access to industrial areas
or parks, and typically carry heavier trucks than
the business class.
Less than 200 2-4 4.0 - 5.0 in.
(100-125 mm)
200-1,000 10-50 5.0 - 7.0 in.
(125-175175 mm)
1,000-8,000 50-500 5.5 - 9.0 in.
(135-225 mm)
11,000-17,000 400-700 6.0 - 9.0 in.
(150-225 mm)
2,000-4,000 300-800 7.0 - 10.5 in.
(175-260 mm)
Arterial
Streets that serve traffic from major 4,000-15,000 (minor) 300-600 6.0 - 9.0 in.
expressways and carry traffic through
4,000-30,000
(150-225 mm)
metropolitan areas. Truck and bus routes are
(major)
7.0 - 11.0 in.
primarily on these roads.
700-1,500
(175-275 mm)

Subgrade Properties
Subgrade Soil Types and Approximate k Values
Type of Soil Support k value range)
Fine-grained soils in which
silt and clay-size
Low
particles predominate
Sands and sand-gravel
mixtures with moderate Medium
amounts of silt and clay
Sands and sand-gravel
mixtures it relatively lti l free
High
of plastic fines
75 - 120 pci
(20 - 34 MPa/m)
130 - 170 pci
(35 - 49 MPa/m)
180 - 220 pci
(50 - 60 MPa/m)

Subgrade Properties
Typical composite k-values for unbound granular, aggregate, or crushed stone subbase
Thickness of Unbound Granular or Crushed Stone
Subgrade k-
Subbase
value (pci) 4” 6” 9” 12”
50 65 75 85 110
100 130 140 160 190
150 176 185 215 255
200 220 230 270 320

Subgrade and Subbase
Subgrade strength is not a critical element in the
thickness design.
Has little impact on thickness.
Need to know if pavement is on:
Subgrade (k ≈100 psi/in.)
Granular subbase (k ≈ 150 psi/in.)
Asphalt treated t subbase (k ≈ 300 psi/in.)
Cement treated subbase (k ≈ (500 psi/in.)

Subbases as a Design Element
Assuming that a plain jointed doweled concrete
pavement was designed d with these k values (90%
reliability, 10 million ESALS), the effect on concrete
thickness follows:
No subbase, PCC thickness = 10.23 in.
4-in. dense-graded aggregate, 10.18 in.
6-in. dense-graded aggregate, 10.14 in.
12-in. dense-graded aggregate, 10.01 in.
4-in. cement stabilized subbase, 9.9797 in.
6-in. cement stabilized subbase, 9.79 in.

Subgrade and Subbase
Proper design and construction are absolutely
necessary if the pavement is to perform.
Must be uniform throughout pavement’s life.
Subbases can contribute to the constructability of a
concrete pavement under adverse conditions
Poor subgrade/subbase preparation can not be
overcome with thickness.

WWW.TRB.ORG/MEPDG

Pavement Design Factors
Climate
Traffic
Materials
Structure
Damage
Response
Time
Damage
Accumulation
Field Distress

JPCP Raw Input (Level 1, 2, or 3)
Environment
• Temperature
Materials
• PCC
Traffic
• Axle classification
• Precipitation •Base
• Subgrade
•Axle loads
Process raw input for PCC distress modeling
Ti Trial lDesign
Assemble input and trial design information for each distress model
Top-down cracking
Bottom-up cracking
Faulting
•Calculate stresses
•Calculate damage
•Predict top-down
cracking
•Calculate stresses
•Calculate damage
•Predict bottom-up
cracking
•Calculate deflections
•Calculate diff. energy
•Predict joint faulting
trial desig gn
Compute IRI over Design Period
(Initial IRI, Distress, Climate,
Subgrade)
Requirements
satisfied?
Yes
Design completed
No
Revise

Cost - Performance Balance
Considerations
Type of facility
Design expectations
Budget constraints

What do we mean by
economizing...?

Is it about “Cheap”?
Cost
Performance

The question becomes…
Cost
Performance
What is the optimum design for the expected performance?

Selecting Appropriate Features
Subgrade
Compact
Treat/Stabilize
Subbase
Unstabilized
Cement Stabilized
GAB+ AC
GAB
Joint Spacing
20 ft
15 ft
Dowels
Full basket
Partial basket
Tiebars
Number
Spacing
Joint Sealant
None
Hot pour
Silicone
Preformed

Selecting Appropriate Features
Thickness
8 in.
Full-depth Concrete
10 in.
Partial-Depth Concrete
12 in.
Asphalt
14 in. RCC
Widened lane
Shoulder

Effect of Base Thickness on PCC Thickness
93 guide (widened lane +dowels)
Subgrade k value is 150 psi
GAB(inch) Kvalue PCC (inch)
12 245 12 .00
10 220 12.06
8 190 12.13
12 GAB+3 AC 290 11.91

Base Thickness
GDOT GUIDELINES
SSV
GAB THICKNESS
20 2.0–2.5 25 12-1010 inches
2.6-3.0 10-8 inches
3135 3.1-3.5 8-6 inches

STREETPAVE

STREETPAVE

MEPDG
Effect of Selection of
Design Features
es

Sensitivity of JPCP Cracking to
Slab Thickness and Joint Spacing
slabs cracked
ercent
P
100
90
80
70
60
50
40
30
20
10
0
19 million trucks (TTC 2 [30 million ESALs])
Wet-freeze climate
8- to 11-in JPCP; 6-in aggregate base
8-in slab
9-in slab
10-in slab
11-in slab
12 13 14 15 16 17 18 19 20
Joint spacing, ft

Effect of Dowel Diameter on Faulting
0.3
0.25
19 million trucks
Wet-freeze climate
10-in JPCP; 6-in aggregate base
EROD=4
AC shoulder
15-ft joint spacing
Faulting, in
0.2
0.15
01 0.1
no dowels
d = 1 in
d = 1.25 in
d = 1.375 in
d = 1.5 in
0.05
0
0 50 100 150 200 250 300
Age, months

WIDENED LANES

EXAMPLE PROJECT
9 INCH PCC, 8 INCH GAB, 12FT OSL
Predicted Cracking
100
90
80
70
Percent slabs cracked
Cracked at specified reliability
Limit percent slabs cracked
Percent slabs cracke ed, %
60
50
40
30
20
10
0
0 2 4 6 8 10 12 14 16 18 20 22
Pavement age, years

EXAMPLE PROJECT
9 INCH PCC, 8 INCH GAB, 13FT OSL
Predicted Cracking
100
90
80
Pe ercent slabs cra acked, %
70
60
50
40
30
20
Percent slabs cracked
Cracked at specified reliability
Limit percent slabs cracked
10
0
0 2 4 6 8 10 12 14 16 18 20 22
Pavement age, years

Cost
Performance
What is the optimum design for the expected performance?

Law of Diminishing Returns…
Adding bells and whistles
Pav vement Pe erformanc ce
Cost of Additional Features

Parking Lots
Pervious Concrete Pavements
Roller Compacted Concrete

What is Pervious Concrete?
• AN
No-Fines
Concrete Mix
• Coarse Aggregate
• Portland Cement
• Water
• Intended for use as
an open-graded
drainage material

Uses
• Commercial parking
lots and driveways.
• Residential parking
lots and driveways.
• Sidewalks & Streets
• Jogging trails
• Embankments for
erosion control etc.

Pervious Concrete Pavements:
Environmental Advantages
• Percolation recharges
groundwater
• Water resources are
conserved
• Less need for irrigation
• Adjacent vegetation
allowed more
rainwater
• Reduced runoff
• Cooler surface has
less impact on air
temperature

Pervious Concrete Properties
• Drainage rate = 3 to 5
gal/min/ft /ft 2
• Equivalent of 275” to
450” of rain per hour!
• Water drains through
pavement and stone
bed and infiltrates
slowly into underlying
soil mantle
• 0.1 – 0.5 in/hr preferred
• System design may be
customized for unique soil
conditions

Pervious Concrete Properties
• 15% to 30% air void content
• Field studies show 20-25% average
• 100 to 120 lbs/ft 3 unit weight
• 2500 to 3500 psi strength*
• Introduction ti of small amount of ffine aggregate
can increase strength to 4000 psi (+/-)
• compressive strength typically y not used as
acceptance criteria. Air void structure and unit
weight are used instead.

System Hydrological Design
Considerations
• Required Input
• Soil permeability
• Porosity of pervious concrete
• Thickness of pervious concrete
• Local rainfall data
• Adjacent areas that will drain onto pervious

Typical System Structure Design:
Cross-section diagram
Pervious Concrete
Compacted Sub-basebase
(#57/#67 Stone)
Filter Fabric
mum
2 feet mini
Compacted Sub-grade
(92% max)
Water Table
(wet season level)

Application Selection
Two Way ADTT
Application Pavement
Thickness
MR
Light Residential
3 6” 150-350 Psi
(Driveways)
Residential – Non Critical
(Side Walks & Jogging
0 4” 150 Psi
Trails, Patios)
Medium Residential
10-30 8” 350 Psi
(Residential & Secondary)
Light Commercial
(Parking Lots)
10-30 8” 350 Psi

Case Studies

Tree Protection, Stormwater Management, Run-off Quality
Improvement, Reflective “Cool” Surface Color Make Pervious Concrete
Pavement an Excellent Choice for Parking Lots

The Pervious Concrete Paving Rapidly Absorbs the
The Pervious Concrete Paving Rapidly Absorbs the
Run-off During Rain Showers

Wilmington, NC: Costco

Wilmington, NC: Halyburton & Ann
McCrary City Parks

East Atlanta Library
• All parking areas and a pedestrian plaza
• System captures all rainfall on site
• Features color concrete & underground
storage chamber
• Small site – limited parking

Silver LEED Library- parking area

University Of Tennessee/ Chattanooga
Finley Stadium Parking Lot (1997)

LEED CREDITS OBTAINED WITH
PERVIOUS CONCRETE (from ACI 522)
• SS-C6.1&6.2 Stormwater Design
• SS-C7.1
• WE C1.1
Heat island Effect non roof
Water Efficient Landscaping
• MR-C4.1&4.2 Recycled Content
• MR-C5.1&5.2 Regional Materials

Satellite Infrared Imaging – ATL Airport
Asphalt Parking Lots Concrete
Parking Decks
Concrete Runways

SS Credit 7.1: Heat Island Effect
(Non-roof)
• Provide shade (within five years) on at least
30% of non-roof impervious surfaces on site,
including parking lots, walkways, etc.
• Use light-colored/high l h albedo materials
(reflectance of at least 0.3) for 30% of the
non-roof impervious surfaces
• Place a minimum of 50% of parking space
underground
• Use open-grid pavement system (net
impervious area less than 50%) for a
minimum of 50% of the parking area.

Albedo : Solar reflectance
• Ordinary gray cement concrete has an
initial albedo in the range of 0.35 – 0.45
• White Cement concrete has an albedo of
0.7 – 0.8
• Slag Cement used in Concrete should
increase the albedo value, while Fly ash
may lower it.
• Asphalt is from 0.0505 – 015 0.15

www.PerviousPavement.org
• Benefits
• Applications
• Performance
• Design Guidelines
• Construction
•Inspection &
maintenance
• Resources

Roller Compacted
Concrete Pavements

Definition
“Roller-Compacted Concrete (RCC) is a no-slump
concrete that is compacted by vibratory rollers.”
‣ Zero slump (consistency of dense graded aggr.)
‣ No forms
‣ No reinforcing steel
‣ No finishing
‣ Consolidated with vibratory rollers
Concrete pavement placed in a different way!

Engineering g Properties
‣Compressive strength (f’ c )
–4,000 to 10,000 psi
‣Flexural strength (MR)
–500 to 1,000 psi
–MR = C(f’ c ) 1/2 where C = 9 (up to 11)
‣Modulus of elasticity
–3,000,000 to 5,500,000 psi
–E = C E (f’ c ) 1/2 where C E = 57,000 (up to 67,000)

Surface Appearance
‣Not as smooth as
conventional
concrete
‣Important p to
recognize difference
‣Similar appearance
to asphalt only light
grey instead of black

RCC vs. AC Intermediate Course
100
#200 #100 #16 #4 1/2" 1"
80
Percen nt Passing
60
40
20
0
0.075 0.150 1.180 2.360 4.750 12.5 25
Sieve Opening (mm)

Compaction Very Important

Applications

Military Facilities
Ft. Lewis, WA ,1986 Ft. Carsons, CO, 2008
Ft. Drum, NY, 1990

Intermodal Facilities
Central Station, Detroit, MI
Burlington Northern, Denver, CO

Port Terminals
Norfolk International
Terminal, VA, 2006
Port of Houston, TX, 2007

Port Terminals
Port of Mobile
RCC being load tested

Distribution Centers
18 acre distribution
center in Austin, TX
10 years after construction

Honda Plant
Lincoln, Alabama

Mercedes-Benz Plant
Vance, Alabama

I-285 Highway
Atlanta, GA
Highway Shoulders

I-75 Tift-Cook Co, GA

GREYSTONE BLVD, COLUMBIA, SC

RICHLAND AV. (US 78) AIKEN, SC

Benefits of RCC Pavements
• Economical (both initial and life-cycle costs)
• High load carrying ability
• Eliminates rutting
• Excellent overall durability
• Simple, fast construction
• No forms or finishing
i

QUESTIONS OR COMMENTS
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