Concrete Pavements Conference 2013 - ASCP Presentation 03.pdf · ASCP Concrete Pavements Conference...

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Concrete Pavements Conference 201312 August 2013

US Precast Concrete Pavement

Technology & Directions

Shiraz Tayabji

Applied Research Associates, Inc.

Elkridge, Maryland

Presentation Outline

� Precast concrete pavement (PCP) background

� US PCP applications & systems

� US experience todate

� Technical considerations

� Case studies

ASCP Concrete Pavements Conference 2013

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Preamble

The research objective of the recently completed SHRP 2 highway renewal area was to achieve highway system renewal that is performed rapidly, causes minimum disruption, and produces long-lived facilities.

A tactic for rapid renewal is to minimize field fabrication effort and speed the on-site construction phase of the work that actually impacts traffic. However, shorter facility life spans cannot be accepted as the

price of rapid renewal.

Rapid renewal and longer service life can be achieved using precast concrete pavements

This presentation provides an update on the US precast concrete pavement technology based on a SHRP2 study and other on-going US

activities


Precast Concrete Pavement Background

� A recent technology – production use in US since 2001

� Used primarily for RAPID repair & rehabilitation &

longer-lasting treatments

� Typically, night-time work & short work windows

� Typically, repair/rehab along a single lane

� Multiple-lane repair/rehab possible based on site constraints

� Typical production rates/closure

� 15 to 20 repairs

� 30 to 40 panels for continuous jointed PCP (up to 200 m)

� Up to 200 m for prestressed PCP


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Precast Concrete Pavement Applications


Intermittent repair along a section of I-295 in New Jersey


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Placement of jointed precast

concrete panels in

Minnesota.

Outside lane and shoulder

replaced with precast prestressed

concrete pavement in Delaware.


Placement of a

precast concrete

panel spanning two

traffic lanes on I-66

in Virginia.

Four lanes (including

outside rush-hour

shoulder lane) replaced

with precast prestressed

concrete panels on I-66

in Virginia.


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Post-tensioning a series of 11 m long x 3.65 m wide panels on I-680 in California


Lane Closure Requirements

� An over-riding assumption for use of PCP

is that some level of traffic operation will be

maintained

� Single-lane repair/rehab – need at least a two-

lane closure & at least one lane for traffic

� Two-lane repair/rehab – need at least a three-

lane closure & at least one lane for traffic

� Otherwise, intermittent full traffic stoppage

may be necessary (not preferred)


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� For intermittent repairs

� Nominally reinforced panels

� Prestressed (pretensioned) panels

� For continuous Applications

� Jointed PCP systems (JPrCP)

� Nominally reinforced panels

� Prestressed (pretensioned) panels

� Post-tensioned systems (PPCP) - fewer

active joints; longer sections

� Incrementally connected PCP (ICPCP)

� Simulates JRCP: intermediate joints

locked-up

� Fewer active joints; < 30 m long sections

Precast Pavement Applications


� Precast prestressed pavement (Texas system)� Non-proprietary (FHWA sponsored)

� Precast jointed pavement� Non-proprietary

� Michigan system (FHWA sponsored)

� Illinois Tollway, etc.

� Proprietary/Vendor-Specific� Fort Miller system

� Roman Stone

� Other

� System components – Off-the-shelf or proprietary

Precast Concrete Pavement Systems


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PCP Systems in Use (USA)


Intermittent Repair

Conventional Jointed PCP System

PPCP Systems – Variable width (3.65+ m), variable length (3 to 11 m used todate) (in use in Indonesia also)

PCP Systems in Use (USA) - Posttensioned


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Current State of PracticeThe Posttensioned System ( U of Texas Developed)

Current State of Practice

Roman Stone System Michigan System Fort Miller System

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Current State of Practice

The Kwik Slab SystemThe PANY System

LaGuardia Airport, NY

The Illinois Tollway System

� Heavily-traveled main line interstate/primary system & urban roadways� Huge need on aging interstates built 40 – 50 years ago� The very best place to use premium repair material

� Interstate/primary system & urban ramps� Often no alternative routes and heavy traffic

� Intersections� Some can not be closed

� Bridge approach slabs� A large no. of approach slabs across country need to be rehabilitated

� Bus pads� Where alternative bus stop locations are not acceptable

Where to Use Precast Pavement?


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� US/Canada

� Production use

� CA, IL Tollway, IA, NJ, NY, UT, VA

� Ontario, Quebec

� Demos

� CO, DE, FL, GA, HI, MI, MN, MO, NV, OH, PA, TX,

WI

� Airfield

� PANY/NJ, Dulles airport, USAF

Precast Pavements - Users


� Canada – Based on US practices

� The Netherlands – The ModieSlab system

� Japan - for highway, airport and tunnels

� Russia (Soviet Union) - precast pavements for airfields & highways

� France - Removable hexagonal panels in urban areas

� Indonesia - New PPCP construction (rural – 35 km & more)

International PCP Practices


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Structural Design Considerations

� Intermittent repairs (Service life > 15 to 20+ years)� Same or a little less thick panels as existing PCCP

� Generally higher strength concrete & reinforcement

� Continuous jointed (Long-life; > 30 to 40+ years)� Depending on traffic, panels need to be same thickness as

new slab or 25 to 50 mm less

� Generally higher strength concrete & reinforcement

� Continuous prestressed (Long-life; > 30 to 40+ years)� Panels 75 to 100 mm less than new slab (using at least 1.4

MPa effective prestress at midsection)

� Prestress system design need to be developed (strand diam. & spacing =>postensioned section length)

� Expansion joint design


� Constructability (as affected by system

design & site conditions)

� Concrete durability (not an issue)

� Pavement performance, as affected by

� Load transfer at joints

� Panel support condition

Key PCP Technical Considerations


PCPs ARE NOT “SUPER” PAVEMENTS; ONCE INSTALLED, PCPs

BEHAVE SIMILAR TO CONVENTIONAL CONCRETE PAVEMENTS.

�Only the method of construction is different

THE CONCRETE & THE PANELS CAN BE VERY DURABLE

However, uniform support condition & good load transfer at joints

are critical

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� For repairs� Method 1: Dowels are drilled and epoxy-grouted along existing pavement sides of joint & dowel slots in panel

� Method 2: Dowels embedded in the panel & dowel slots cut in existing pavement

� Method 3: Dowel slots cut in panel & existing pavement

� For continuous applications:� Dowels embedded along one side of the panels & dowel slots at other side of the panel (top or bottom)

� Dowel slots along both sides of the panels

Joint Load Transfer Considerations


� Use of existing base

� Granular� Reworked, compacted & regraded

� Reworked, compacted, regraded & bedding material applied

� Stabilized� Used as is or trimmed; bedding material applied

� Bedding material� < 6 mm fine-grained granular material

� Thicker layer of RSFF or polyurethane grout

� New base – granular or rapid-setting LCB

Panel Support Considerations


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� Compaction testing typically not performed on

finished granular base/bedding; moisture control not

attempted

� Use of LWD is recommended for compaction monitoring

� Granular base/bedding trimming is time consuming,

requiring multiple passes (need a rapid auto-grading

system)

Panel Support Issues


Installation of Precast Panels

� Site survey – identify needed panel dimensions

� Fabricating precast panels at plant

� Transporting panels to the site

� Removal of old pavement

� Preparing base/subbase

� Installing panels on finished base

� Interconnecting panels using dowel/slot system

� Post-tensioning panels (design option)

� Grouting dowel/tie-bar slots (design option)

� Injecting bedding grout to firmly seat panels (design option)


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Repair Panel Installation Options

Existing Slab Existing Slab

Existing Base

Precast Panel

Prepared bedding (Granular or

flowable concrete)

Existing Slab Existing Slab

Existing Base

Precast Panel

Rapid-setting grout or polyurethane Adjustable Beam

� SHRP2 Project R05 deflection testing indicate good load transfer and good deflection response at transverse joints of JPrCP systems used for repair and continuous applications.

� The PPCP systems exhibited higher deflections and lower load transfer at the expansion joints. However, since these expansion joints are 50 to 80 m apart, the potential for significant joint related distress is low.

� The behavior and performance of the constructed PCP systems appear to be similar to that of like cast-in-place concrete pavements.

Findings Based on Field Testing


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� Cost continues to be an issue

� Base treatment & bedding use

� On-site QA/QC focus

� Availability of local precasters interested in

this market needs improvement

o Expected to improve as market size increases

� Proprietary products issue

� Limited competition in the marketplace

� Agency/contractor staff training

Continuing Issues to be Addressed


� PCP technology is a mature, but still evolving, technology that shows great potential for rapid repair and rehabilitation of existing pavements

� Although experience with PCP systems is limited, less than 14 years, performance todate indicate that well-designed and well-constructed PCP systems can be expected to provide long-term service

Summary


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Thank [email protected]

� Project detailso Precast pavement system: Fort Miller’s Super Slab system

o Panel thickness: 8.75 in. (existing JRCP thickness – 9 in.)

o Panel dimensions: length – variable (8, 10, 12 ft); Width – 12 ft

o Number of panels installed: 277

o Base: existing sandy granular base

o Joints: Doweled transverse joints; longitudinal joints not tied

o Traffic level: Heavy freeway traffic with heavy truck volume

(140,000 vpd)

o Existing JRCP joint spacing: 78 ft

� Performance – good (May 2010)

NJ I-295 - Repair (2008)

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NJ I-295 (June 2008) Intermittent Repairs using the Super Slab System

�Process:o Sawcut repair boundaries in advance

o Night of repair – remove damaged panel; prepare base; drill dowel holes in existing panels; insert dowel bars; install precast panel

o Next night – patch dowel slots; underseal panel

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NJ I-295 (June 2008) Intermittent Repairs

NEXT

NIGHT

��

34

FIRTST NIGHT

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NYS I-495, Near JFK Airport (2011) Intermittent Repairs using the Roman Road System

� Details:o 4 miles (both directions) full depth repairs

o Over 800 panels – Panels mostly 8 ft long by 12 ft wide, some 10 ft long; t = 9 in.

o Bedding: Uretek HD polyurethane foam

o Load transfer: Full DBR

o Traffic: 200,000 vpd

� Process:o Mill existing AC overlay

o Sawcut repair boundaries in advance

o Night of repair – remove damaged panel; prepare base; install precast panel; inject urethane foam to raise panel

o Next night – Cut dowel slots; install dowel bars (DBR)

� Performance - Good

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NYS I-495, Near JFK Airport (2011) Intermittent Repairs using the Roman Road System

Installation under Heavy

Traffic – at Night 36

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o Panel thickness: 10 in.

o Panel dimensions: length –18 ft; Width – 10 ft (toll plaza drive lanes; 12 lanes)

o Number of panels installed: 1,071

o Base: existing granular base (top 2 in. removed) with 1.5 in. leveling stone dust

o Joints: Doweled transverse joints; longitudinal joints tied

o Total project area: over 40,000 y2 (both sides of the toll booths)

o Traffic level: Heavy commuter traffic (New York city area) with large number of trucks per day (eastbound through toll plaza -72,000 vpd)


Tappan Zee Jointed (Oldest - 2001)

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Tappan Zee Jointed (Oldest - 2001)

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o Panel thickness: 8.75 in.

o Panel dimensions: length – 15 ft (a few shorter panels to accommodate ramp curvature); Width – 12 ft

o Number of panels installed: 224

o Base: existing gran. base with up to 0.25 in. leveling stone dust

o Joints: Doweled transverse joints; inside longitudinal joint (ramp centerline joint) tied to existing JRCP

o Total project length: 3,552 ft

o Traffic level: Moderate commuter traffic (Washington, DC area) with low level of truck traffic (55,000 vpd)

� Performance – Good (some cracking)

Virginia Jointed (2009)

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Virginia Jointed (2009)

40

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� Project detailso Panel thickness: 8.75 in.

o Panel dimensions: length – 10 ft; Width – 12 ft (two inside lanes) and 27 ft (two 12 ft outside lanes and 3 ft shoulder). Base: existing aggregate with up to 0.5 in. leveling stone dust

o Subbase: 6 in. cement stabilized subgrade

o Panel/base interface: geotextile fabric

o No. of panels post-tensioned together: 11 (end segments) or 16

o Post-tensioning method: from expansion joints

o Total project length: 1,020 ft; Total no. of expansion joints: 8

o Traffic level: Heavy commuter traffic (Washington, DC area) with large no. of trucks per day (184,000 vpd with 5% trucks)


Virginia PPCP (2009)

Virginia PPCP (2009)

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• Thousands of distressed approach slabs exist– Exhibited by classic “bump” at bridge end/approach

• Causes of failure – Settlement of underlying soils

– Erosion of embankment materials

• Difficult to replace – Limited room for staging – narrow shoulders

– Often repaired with “band-aid” materials

• Precast panels - a good fast and permanent repair– Full-depth replacement allows opportunity to repair underlying embankment

– Can be installed in over night or over-the-weekend work windows

Bridge Approach Slabs

NY State DOTNY State DOT

Example: Approach Slab on Existing Bridge Abutments

Cross Section at End of Existing Bridge

Placing panel Over Anchor Rods

Placing panels In One Lane

Source: The Fort Miller Co., Inc.

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