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Cuál método de diseño se debe utilizar para una aplicación específica

TALLER DE DISEÑO DE PAVIMENTOS DE

CONCRETO

November 7, 2014

Robert Rodden, P.E.

Senior Director of

Pavement Technology

Design for What?

Different cement-based materialsJointed- or continuously-reinforced

Roller-compacted concrete (RCC)

Pervious concrete

Composite pavements

Different applications/trafficAircraft loading

Industrial loading

Other odd loading

Short joint spacing

How Did We Get to Jointed Plain Being the Norm for Over-the-Road Traffic?

Design Challenge | Solution

Horseshoes/Steel Wheels & Mud | Concrete

Early Concrete Pavement Details

The first concrete pavements/slabs were:

≈ 6” (150 mm) thick… no structural design because focus was rut prevention

6-8 ft (1.8-2.4 m) squares based on mixer capacity… yes, joint spacing was dictated by mixer capacity!

No crack control joints or dowels/steel

Design Challenge | Solution

Speed of Vehicles Increases so People Notice Joint Roughness & Want to Maximize Production to Minimize Cost | Minimize Construction Joints

less

and more

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Advances Brought New Challenges

More efficient equipment and placement methods were soon developed

Slabs got longer

The public wanted 2-lane roadways for safety

Slabs got wider

… both of these lead to new challenges

First mile of PCCP(1909)

Concrete Wants to Shrink

Drying Shrinkage

Hydration Uses Water

Thermal Shrinkage

Hot then Cold

HOT AT SET∆ ∗ ∆ ∗

ChemicalShrinkage

COOLED OFF

Shrinkage + Restraint = CRACKS!?!

HOT AT SET, HIGH MOISTURE, UNHYDRATED CEMENT

COOL, DRY, HYDRATED CEMENT

TEFLON | No Friction/Restraint

If no restraint

With restraint

Subgrade/Subbase | Restraint

Design Challenge | Solution

Shrinkage Cracking | Thicken CL; Let It Crack Transversely

40-80 ft

(12-24m)

15-20 ft

(4.6-6.1 m)

Design Challenge | Solution

Crack Opening | Reinforce to Hold Crack Tightly

THE BIRTH OF Jointed Reinforced Concrete Pavement - JRCP (1913 or Earlier)

Plan

Profile

Steel: 0.06-0.25% Joints: 40-100 ft (12-30 m)Cracks: 15-20 ft (4.6-6.1 m)

14-20 ft(4.3-6.1 m)

Design Challenge | Solution

Crack Maintenance | Create Straight Transverse JointsPlan

Profile

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Design Challenge | Solution

Construction Joint Faulting/Chipping | Dowel Joints

JPCP Profile

THE BIRTH OF DOWELED Jointed Plain Concrete Pavement - JPCP (1917)

JRCP Profile

Long Panels = Higher Risk of BlowupsBlowup

RiskHigh

Low

JRCP w/ 80-100 ft joints

(24-30 m)

JRCP w/ <40 ft joints

(<12 m)

JPCP w/ 40-80 ft joints

(12-24 m)

JPCP w/ 15-25 ft joints

(4.6-7.6 m)

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Design Challenge | Solution

Blowup | Include Expansion Joint if JRCP or long JPCP

Design Challenge | Solution

Crack Faulting | Reinforce MORE to Hold Crack Tightly

THE BIRTH OF Continuously Reinforced Concrete Pavement - CRCP (1923)

Plan

Profile

Steel: 0.6-0.85% Cracks: 2-6 ft (0.6-1.8 m)

WWII + TRAFFIC = Faulting of Undoweled Design Challenge | Solution

Pumping/Faulting | Add a Subbase

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The Jointing Dilemma Continued…

During WWII (1939-1945), Bureau of Public Roads encouraged steel-free designs to free up steel for the war effort. So the norm became undoweled JPCP with expansion joints at 105-120 ft (32-37 m), which had contraction joints open and poor performance. These pavements were relatively free of cracking, spalling and blowups, but the faulting was serious.

After WWII, typically either undoweled JPCP with short joints and no expansion joints or long jointed JRCP with contraction/expansion joints at 50 to 100 ft (15 to 30 m).

…and Continued

In the 1940s the US Bureau of Public Roads did a study on expansion joints

Showed that they progressively close over the years, causing greater openings at nearby contraction joints and resulting in loss of aggregate interlock and sealant failure.

Showed that expansion joints are not necessary unless contraction joints spaced at greater than 60 ft (18 m), aggregates are expansive, or temp during construction is near freezing.

We Even Tried a “Hinge Joint” Design

http://www.fhwa.dot.gov/pavement/concrete/hpcp/hpcp05.cfm

The Three Traditional Types

Design Challenge JPCP JRCP CRCP

Transverse Joint Spacing 14-20 ft (4.3-6.1 m) 22-100+ ft (6.7-30 m) N/A

Transverse Crack Spacing N/A 15-20 ft (4.6-6.1 m) 2-6 ft (0.6-1.8 m)

Rut-Resistant Surface Yes Yes Yes

Shrinkage Accounted for by Jointing Cracking Cracking

Reinforcing N/A 0.06 – 0.25% 0.6-0.85%

Expansion Joints Used No Sometimes Maybe

Tiebars Used in Long Joints Yes Yes Yes

Longitudinal Joint Spacing 12-14 ft (3.7-4.3 m) 12-14 ft (3.7-4.3 m) 12-14 ft (3.7-4.3 m)

Trying to Minimize the Number of Man-Made Joints – WHY?

YES YES YES

AASHTO 62-93 Design Yes Yes Yes

AASHTO DARWin-ME Design Yes NO Yes

U.S. Design Standards for Roadways

AASHTOWarePavement ME (previously known as DARWin-ME and MEPDG)

AASHTO 93 (software as ACPA WinPAS)

ACPA StreetPave

325 & 330

Most Roadway Concrete in the US is JPCP

JPCP

JRCP

CRCP

Pavement-ME and StreetPave do not supported Jointed

Reinforced Concrete Pavement (JRCP)

design

0% 20% 40% 60% 80% 100%

ArizonaArkansasDelaware

FloridaHawaiiIdaho

IndianaIowa

KansasMichiganMissouriMontanaNevada

North CarolinaOhio

OklahomaSouth CarolinaSouth Dakota

TennesseeUtah

VirginiaWashington

West VirginiaWisconsinWyoming

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Continuously Reinforced Concrete Pavement (CRCP) Design

Guidance on CRCP Design

FHWA & CRSI initiative: http://www.crcpavement.org/

AASHTO 93 or ME can design

Several state agencies havetheir own custom design

IL – custom ME design

TX – TSLAB86

Roller-Compacted Concrete (RCC) Thickness Design

RCC Thickness Design

RCC-Pave available from PCA:http://www.cement.org/bookstore/profile.asp?id=2309

Same “core” as ACPA AirPave / PCA’s AIRPORTUnlimited fatigue when stress ratio ≤ 0.50; no faulting / IRI models

Some suggest using StreetPaveACPA does not support this

ACPA working on new RCC fatiguemodels right now

RCC design currently like the Wild West

RCC Fatigue

Pervious Concrete Thickness Design

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Reasons for ACPA’s PerviousPave

Several hydrological design methods exist

No universal structural design method before PerviousPavesome used Westergaard solutions

some suggested to use StreetPave – recommended in at least two widely-circulated resources/journals

Delatte’s TRB 2007 Paper:

“The author investigated adaptation of ACPA StreetPave software…”

From StreetPave to PerviousPave

Key changes :

Exclusion of erosion

Different design variablesmaximum strength andcorrelation to modulus

no dowel bars

traffic distribution defaults

allowable subgrades/subbases

Inclusion of hydrological design

acpa.org/PerviousPave

Composite Pavement Thickness Design:Asphalt on Concrete

Asphalt on Concrete Composite

Some consider renewable surface

Asphalt surface might provide thermal benefits that ultimately reduce concrete slab curling which then extends performance

NCHRP Report S2-R21-RR-2 from July 2013:

http://onlinepubs.trb.org/onlinepubs/shrp2/SHRP2_S2-R21-RR-2.pdf

MEPDG-based design

Composite Pavement Thickness Design:Concrete on Concrete

Concrete on Concrete Composite

Wet-on-wet concrete placement that might provide structural, cost, sustainability, performance, etc. benefit(s)

NCHRP Report S2-R21-RR-3 from July 2013:

http://onlinepubs.trb.org/onlinepubs/shrp2/SHRP2_S2-R21-RR-3.pdf

MEPDG-based design in this report but other design methods might also be valid, depending on setup

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Aircraft Loading

Boeing 777-200ERGear Spacing 84 feet 11 inchesEquates to 3.4 California Profilograph lengths

Image Courtesy Boeing Commercial Aircraft Company

Aircraft Loading

One aircraft wheel load can easily exceed the total gross weight of many vehicles, including semi-tractor trailers

Aircraft wheel loads are approaching 65,000 lb (29,500 kg) and tire pressures exceed 200 psi (1.4 MPa)

Tri-Services (Army, Air Force, Navy)

PCASE = Pavement-Transportation Computer Assisted Structural Engineering

US Army Corps of Engineers product

https://transportation.wes.army.mil/pcase

ACPA’s AirPave

AirPave is based on calculated pavement responses (mechanics –independent of climate)

Developed as an update to PCA’s AIRPORT, originally developed by Bob Packard

Design is strictly mechanistic and limit stress ratio; no faulting / IRI

acpa.org/AirPave

Now it is more of an analysis tool…

FAARField

FAA standard for airfield pavement design

Rigid pavement design based on 3D finite element analyses

http://www.faa.gov/airports/engineering/design_software/

Industrial Loading

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Industrial Loading

Design MethodOver-the-Road

TrucksIndustrial Vehicles

Distributed Loads

Concentrated Loads

AASHTO 93 / ACPA WinPAS X

AASHTOWare Pavement ME X

ACI 330.X (non-software) X X X

ACPA AirPave X X

ACPA IndustrialPave (SOON!) X X X X

ACPA StreetPave X

EverFE X X

TCPavements OptiPave X

NOTE: ACI 330.X uses ACPA’s StreetPave in its Over-the-Road Trucks design tables and ACPA’s AirPave in its Industrial Vehicles design tables; the document also mentions OptiPave and both AASHTO software

IndustrialPave

Beta almost complete

Includes:Over-the-Road Trucks – based on StreetPave

Industrial Vehicles – based on AirPave

Distributed Loads – based on AirPave

Concentrated Loads – based on ACI 318 equations

Thinking about including RCC design in the software

Other Odd Loading

Other Odd Loading

Of course can use Westergaard or AirPave

Best bet is usually to turn to some finite element analysis

EverFE

FREE!!!!

3D user-friendly FEA software

Based on calculated pavement responses (mechanics –independent of climate)

Focus is ???

Design is strictly mechanistic

http://www.civil.umaine.edu/everfe/

EverFE is Very Powerful!

Dowel alignment, joint spacing / layout effects, etc.

12 ft12 ft 12 ft 12 ft 12 ft

15 ft

6 ft 12 ft12 ft 12 ft 12 ft

15 ft

6 ft

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Thank you.Questions? FEEDBACK!

Main Website | acpa.orgConcrete Wiki | wiki.acpa.org

App Library | apps.acpa.orgDesktop Software | software.acpa.org

Resources | resources.acpa.orgOn-Demand Training | ondemand.acpa.org

Live Online Training | webinars.acpa.orgYour Local Contact | local.acpa.org

Robert Rodden, P.E.

Senior Director of Pavement Technology

American Concrete Pavement Association

rrodden@acpa.org | 847.423.8706