Precast Concrete Panel Systems for

Full-Depth Pavement Repairs

Field Trials

PUBLICATION NO. FHWA-HIF-07-019 FEBRUARY 2007

abcd

Office of Infrastructure

Office of Pavement Technology

Washington, DC 20590
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This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document. This report does not 

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Technical Report Documentation Page 

1. Report No. 

FHWA-HIF-07-019 

2. Government Accession No. 3. Recipient's Catalog No. 

5. Report Date 

February 2007 

4. Title and Subtitle 

Precast Concrete Panel Systems for Full-Depth Pavement 

Repairs: Field Trials 6. Performing Organization Code 

7. Author(s) 

Neeraj Buch, Ph.D. 

8. Performing Organization Report No. 

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) 

Department of Civil and Environmental Engineering 

Michigan State University 

3546 Engineering Building 

East Lansing MI 48824-1226 

11. Contract or Grant No. 

BAA DTFH61-03-R-00003 

13. Type of Report and Period Covered 

Final Report 

March 2003 – March 2006 

12. Sponsoring Agency Name and Address 

Office of Pavement Technology 

Federal Highway Administration 

U.S. Department of Transportation 

400 Seventh Street SW, Washington, DC 20590 

14. Sponsoring Agency Code 

HIPT-20 

15. Supplementary Notes 

Performed under the Concrete Pavement Technology Program. Contracting Officer’s Technical 

Representative: Sam Tyson, Office of Pavement Technology, Federal Highway Administration 

16. Abstract 

The use of precast slabs as an alternative to conventional cast-in-place repairs may be an effective 

means of reducing construction time, thereby minimizing user delay and travel costs while obtaining a 

long-lasting, durable repair. This report summarizes the 3-year study, “Field Trials of Concrete Pavement Product and Process Technology—Precast Concrete System for Rapid Repairs,” in which precast 

slabs were used for joint repair and slab replacement on in-service Michigan and Colorado highways. 

Cast-in-place, full-depth patches were installed as controls. The report contains a summary of the relevant literature; summaries of the field trials and their findings regarding efficiency and durability; recommendations for precast panel installation; a sample distress documentation report; a presentation of 

construction guidelines; and a sample special provision specification developed as part of the study. 

Recommendations for consecutive slab repairs are to reduce slab length; use a slab thickness of 200 mm 

or greater; use dowels to connect precast panels to existing panels for joint flexibility and load transfer; 

maximize proximity of repair sections when planning and encourage multitasking during panel installation to reduce construction time. For isolated repairs it is recommended that four dowel bars be placed 

in the wheel path and provide an expansion cap at one end of the dowel bar to accommodate slab 

movement due to environmental loading and prevent closing of the joint. 

17. Key Word 

precast concrete panels, concrete pavement rehabilitation, concrete pavement distresses 

18. Distribution Statement 

No restrictions. This document is available to the 

public through the National Technical Information 

Service, Springfield, Virginia 22161. 

19. Security Classif. (of this report) 

Unclassified 

20. Security Classif. (of this page) 

Unclassified 

21. No. of Pages 

80 

22. Price 

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized
 
 iii 

TABLE OF CONTENTS 

List of Figures............................................................................................................................... iv

List of Tables..................................................................................................................................v 

Chapter 1. Introduction.................................................................................................................1

 Background...............................................................................................................................1 

 Objectives .................................................................................................................................1 

 Organization of the Report .......................................................................................................2 

Chapter 2. Summary of the Literature Review...........................................................................3

Chapter 3. Michigan Field Study .................................................................................................7 

 Site Selection ............................................................................................................................7 

 Precast Panel Mixture Design and Fabrication Details ...........................................................7 

 Construction Sequence ...........................................................................................................11 

 Construction Productivity.......................................................................................................18 

 Repair Effectiveness of the Precast Panels.............................................................................21 

 Recommendations for Precast Panel Installation ...................................................................36 

Chapter 4. Colorado Field Study................................................................................................37

 Site Selection ..........................................................................................................................37 

 Precast Panel Mixture Design and Fabrication Details .........................................................38 

 Construction Sequence ...........................................................................................................39 

 Construction Productivity.......................................................................................................44 

 Repair Effectiveness of the Precast Panels.............................................................................48 

 Recommendations for Precast Panel Installation ...................................................................53 

Appendices 

 A. Example of Field Data Sheet .............................................................................................55 

 B. Construction Guidelines Presentation................................................................................59 

 C. Sample Specification for Precast Full-Depth Concrete Pavement Repair.........................69 

References.....................................................................................................................................73 
 iv 

List of Figures 

Figure 1. Structural details of the doweled precast panel ................................................................9 

Figure 2. Fabrication of the doweled precast panels......................................................................10 

Figure 3. Typical distresses............................................................................................................11 

Figure 4. Sawcutting of slab boundaries and slab removal. ..........................................................13 

Figure 5. Initial cleaning and preparation of the base....................................................................13 

Figure 6. Preparation of the load transfer slots..............................................................................14 

Figure 7. Schematic cross section of the dowel assembly.............................................................15 

Figure 8. Precast panel installation and stabilization using high-density polyurethane foam. ......16 

Figure 9. Flowable fill operation and dowel slot backfilling.........................................................17 

Figure 10. Relative distances of patches along the I-675 project. .................................................19 

Figure 11. Construction timeline for panel 5.................................................................................19

Figure 12. Relative distances of patches along the M-25 project..................................................20 

Figure 13. Construction timeline for patches 2 and 3....................................................................21 

Figure 14. Falling-weight deflectometer test locations to evaluate panel effectiveness................21 

Figure 15. Average load transfer efficiencies and deflection ratios for the I-675 test site............23 

Figure 16. Average load transfer efficiencies and deflection ratios for the M-25 test site............28 

Figure 17. Structural response of panels 4 and 9...........................................................................34 

Figure 18. Line sketch illustrating the possible dowel skew and uneven joint opening................35 

Figure 19. Results of the finite element analysis. ..........................................................................35 

Figure 20. Structural details of the precast panel...........................................................................38

Figure 21. Examples of distresses..................................................................................................39 

Figure 22. Slab demolition process................................................................................................41 

Figure 23. Base preparation activities............................................................................................41 

Figure 24. Panel placement process...............................................................................................42 

Figure 25. Fiberglass stitches.........................................................................................................43 

Figure 26. Completed cluster of panels. ........................................................................................44 

Figure 27. Relationship between average elapsed time per panel and the number of panels........47 

Figure 28. Illustration of improvement in operators’ comfort level. .............................................47 

Figure 29. Illustration of advantages of incorporating concurrent activities. ................................48 

Figure 30. Falling-weight deflectometer testing pattern................................................................48 

Figure 31. Average midslab deflections as a function of slab thickness. ......................................49 

Figure 32. Average edge deflections as a function of slab thickness. ...........................................50 

Figure 33. Average joint deflections (approach) as a function of slab thickness. .........................50 

Figure 34. Average joint deflections (leave) as a function of slab thickness. ...............................51 

Figure 35. Typical crack patterns...................................................................................................52 
 v 

List of Tables 

Table 1. Summary of Literature Reviewed......................................................................................3 

Table 2. Summary of Precast Panel Test Sites ................................................................................7 

Table 3. Portland Cement Concrete Mixture Designs for the Precast Panels..................................7 

Table 4. Fresh and Hardened Property Results for the Portland Cement Concrete Mixture...........8 

Table 5. Typical Construction Time, Labor, and Equipment Needs .............................................18 

Table 6. Summary of Approach and Leave Joint Load Transfer Efficiencies...............................24 

Table 7. Summary of Panel Performance, I-675 (Survey Date: 9/14/05)......................................24 

Table 8. Summary of Approach and Leave Joint Load Transfer Efficiencies...............................29 

Table 9. Summary of Panel Performance, M-25 (Survey Date: 9/14/05) .....................................30 

Table 10. Panel Location Summary Along the I-25 Corridor .......................................................37 

Table 11. Portland Cement Concrete Mixture Designs for the Precast Panels..............................38 

Table 12. Compressive Strength of Concrete From the Mead and Loveland Sites.......................39 

Table 13. Mechanical Properties of the Fiberglass Stitch..............................................................43 

Table 14. Equipment Used for Panel Installation ..........................................................................45 

Table 15. Approximate Installation Time for Patches (hours:minutes).........................................46 

 1 

CHAPTER 1. INTRODUCTION 

BACKGROUND 

The traditional practice of rehabilitating concrete pavements is an excellent way to extend the 

remaining service life of the overall pavement network. In most instances, this method of paving 

has satisfied the requirements of the specifying agency. However, the luxury of prolonged lane 

closures is an option whose time is long gone. Increasing traffic volumes and sensitivity to user 

delays and costs have required pavement construction and rehabilitation to be put on a “fast 

track” as much as possible. The objective of fast-track paving is to minimize the time a roadway 

is out of service (Federal Highway Administration [FHWA] 1994). The resulting pavement can 

be opened to traffic (both construction and public) after adequate strength has been achieved. 

Fast-tracking has resulted in the use of chloride accelerators in combination with increased 

cement content to accommodate the short traffic opening times. These modified mixtures are 

susceptible to durability problems. 

Precast structural elements have long been used successfully in the building and bridge industry. 

The authors of this study investigated the feasibility of doweled precast panels as an alternative 

full-depth repair strategy. The use of doweled precast panels provides an attractive alternative 

that can potentially address construction time, short-term and long-term concrete durability, and 

performance issues. The precast panels can be fabricated by using conventional concrete paving 

mixture designs (without the need for setting- or strength-accelerating admixtures) and cured 

under controlled conditions if necessary at a precast plant. Such “factory made” concrete is less 

susceptible to construction and material variability. 

OBJECTIVES 

The objectives of this study were as follows: 

1. Review the literature and document the known practices. 

2. Conceptualize various construction alternatives as they relate to precast 

concrete patches. 

3. Identify potential preventative maintenance projects along in-service concrete 

pavements in Colorado and Michigan, and install precast concrete patches. 

For the purposes of comparison control, cast-in-place full-depth patches were 

also installed. 

4. Investigate the effectiveness and efficiency of precast patches through the 

development of maintenance performance guidelines. 

5. Recommend strategies for monitoring the “newly” installed precast patches. 

6. Produce step-by-step guidelines for the construction of precast concrete 

patches. 

The completion of these objectives is to assist in evaluating the feasibility of precast panels as an 

alternative to conventional full-depth repair of jointed concrete pavements. 
 2 

ORGANIZATION OF THE REPORT 

This final report, which consists of four chapters, summarizes the findings of the 3-year study. 

Chapter 2 provides a summary of the literature concerning precast concrete pavements, and 

Chapters 3 and 4 summarize the Michigan and Colorado field studies, respectively. A sample 

distress documentation report is presented in Appendix A, a presentation of construction 

guidelines is presented in Appendix B, and a sample special provision specification developed as 

part of the study is presented in Appendix C. 
 3 

CHAPTER 2. SUMMARY OF THE LITERATURE REVIEW 

A number of published reports and papers were collected that pertain to the use of precast slabs 

as pavement repair alternatives since the early 1970s. The summary of the reviewed literature is 

presented in Table 1. 

Table 1. Summary of Reviewed Literature 

Source 

Location of 

Construction Summary of Findings 

Bull 1988 A series of laboratory tests on precast concrete slabs was 

conducted in the United Kingdom to develop a computer design 

program to study the impact of slab thickness, steel 

reinforcement, and subbase and subgrade characteristics on the 

performance of precast slabs. 

Correa and Wong 

2003 

The design and construction practices of full-depth repair were 

summarized. Full-depth patches are a repair alternative for the 

following distresses in jointed concrete pavements: low severity 

(or more severe) blowup, corner break, medium-severity (or more 

severe) D-cracking, deterioration adjacent to existing repair, joint 

deterioration, spalling, reactive aggregate, transverse cracking, 

and high-severity longitudinal cracking. For a standard lane width 

of 3.6 m (12 ft), the length of the full-depth patch and the 

remainder are recommended not to be shorter than 1.8 m (6 ft) to 

provide stability and prevent longitudinal cracking. The length of 

the patch should also not exceed the length of the existing slab. 

The use of three dowel bars along each wheelpath was generally 

found sufficient; however, the use of four or five dowel bars 

along each wheelpath is recommended for interstate highways. 

The dowel diameter of 38 mm (1.5 in.) was found to be most cost 

effective. 

Grimsley and 

Morris 1975 

Interstate in an urban 

area in central Florida 

A precast slab was used to replace the entire distressed slab, 

3.7 m (12 ft) wide, 6.1 m (20 ft) long, and 200 mm (8 in.) thick. 

After removal of the existing slab, the precast slab was placed 

approximately 13 mm (0.5 in.) lower than regular surrounding 

elevation. The precast slab was slab-jacked to appropriate 

elevation. The construction caused 8 hours of nighttime traffic 

closure (10 p.m. to 6 a.m.). 

Hachiya et al. 

2001 

Taxiway at the Sendai 

Airport, Japan 

The construction project was to replace distressed slabs at the 

Sendai Airport taxiway with a series of pretensioned slabs 

connected at transverse joints through the application of 

posttensioning. Each slab was 10 m (33 ft) long, 2.5 m (8 ft) 

wide, and 240 mm (9.5 in.) thick. An appropriate posttensioning 

force was applied to prevent joint opening due to typical negative 

temperature gradients at the construction site. The entire 

construction process from removal of distressed slab to 

interconnection of slabs through posttensioning was completed 

within 10 nighttime hours, from 9 p.m. to 7 a.m. 

continued 
 4 

Source 

Location of 

Construction Summary of Findings 

Lane and 

Kazmierowski 

2005 

Highway 427, Toronto, 

Canada 

The trial project investigated the efficacy of three precast 

concrete full-depth repair methods along Highway 427 in 

Toronto. The methods were the Fort Miller Super SlabTM

continuous method, the Fort Miller Super SlabTM intermittent 

method, and the Michigan method. Based on the initial structural 

evaluation, it was concluded that all joints met the minimum 70% 

load transfer efficiency requirement. The precast repairs were 

similar in both ride and appearance to fast-track repairs along the 

same section of the highway. For acceptable elevation matching it 

was recommended that the proper preparation of the base layer is 

very essential. 

Merritt, 

McCullough, and 

Burns 2003 

Frontage road along 

northbound I-35 near 

Georgetown, Texas 

The study was to demonstrate a construction method to replace 

the entire distressed portland cement concrete (PCC) pavement 

system through the use of a prestressed (both pretensioning and 

posttensioning) system. A series of 200-mm (8-in.) pretensioned 

precast slabs of varying sizes (pretensioning strands were in the 

traffic direction) were attached together through continuous shear 

key. When all pretensioned slabs were positioned, posttensioning 

strands in the transverse direction were stretched to tighten the 

slab together and then the posttensioning ducts were grouted. The 

reduction of the time delay of traffic is the main benefit of the 

proposed construction method. 

Meyer and 

McCullough 

1983 

Eastbound of IH-30 

near Mt. Pleasant, 

Texas 

The construction was to repair 200-mm (8-in.) continuously 

reinforced concrete pavements with the use of precast slabs, 

3.7 m by 3.7 m (12 ft by 12 ft) and 1.8 m by 1.8 m (6 ft by 6 ft). 

Polymer methyl-methacrylate was also used in the concrete. The 

construction process consisted of four steps: destroying the failed 

slab, removing the failed slab, installing and aligning the 

precast slab using a wooden frame and a crane, and connecting 

steel using welding and U-bolts. It was found that the connection 

of steel may not be necessary if the polymer is used in the 

concrete. The plan was to evaluate long-term performance of the 

repairs. 

Overacker 1974 Niagara Section of the 

New York State 

Thruway, New York 

Existing pavements that exhibited high-severity fatigue cracking 

were replaced with pretensioned precast slabs with slab sizes 

varying from 3.7 m by 6.1 m by 225 mm (12 ft by 20 ft by 9 in.) 

to 4.0 m by 9.1 m by 225 mm (13 ft by 30 ft by 9 in.). The 

construction work was only allowed from 6:30 p.m. to 6:30 a.m. 

and from 9 a.m. to 3:30 p.m. to avoid traffic congestion during 

commuter hours. The construction process consisted of three 

steps: the distressed roadway was sawed and removed, the precast 

slabs were installed, and the repair areas were overlaid with 

asphalt concrete. 

continued 
 5 

Source 

Location of 

Construction Summary of Findings 

Sharma 1990 I-90 between STH 30 

and USH 18 in Dane 

County, Wisconsin 

Eight different construction variations were used to repair 

distressed joints. One repair method used precast slabs. The 

precast patch was 1.8 m (6 ft) wide and 8.5 in. (216 mm) thick 

and was without any load transfer device. A leveling bed of 

13 mm (0.5 in.) of portland cement mortar grout was laid before 

the precast slab was placed. As compared with sections with load 

transfer devices, the precast section and other sections without 

load transfer devices were found to fault more in 5 years. 

Simonsen 1971 M-59 about 2.5 miles 

east of I-96 in 

Livingston County, 

Michigan 

Four distressed joints were replaced with precast slabs, 3.4 m 

(11 ft) long, 1.8 m (6 ft) wide, and 200 mm (8 in.) thick. Dowel 

bars were used as a load transfer device for two of the slabs, 

while epoxy mortar and filler were used in the other two slabs. 

The construction process consisted of three steps: sawing 

distressed joints with the use of a propelled saw; removing failed 

slabs with the use of an air hammer, a crane, and a truck; and 

installing precast slabs with the use of a drill frame and four 

screw jacks. The lane closure times were about 3.5 and 2.5 hours 

for doweled and undoweled sections, respectively. It was found 

that partial-depth sawing and breaking up the slab with a 

pavement breaker resulted in undercutting and cracking of the 

existing slab. The plan was to construct more precast slabs along 

I-75 – US-23 near Flint in Genesee County, Michigan. 

Simonsen 1972 I-75–US-23 west of the 

Flint in Genesee 

County, Michigan 

This was phase II of the M-59 project. A similar technique was 

used to repair 24 lane joints with precast slabs. Unlike the M-59 

project, this project experienced high traffic volumes where the 

traffic disruption period was required to be short. All the repairs 

were 3 m (10 ft) long and 3.7 m (12 ft) wide with varying 

thicknesses. A crew of seven completed the construction in 

2 days. The average times for the entire process from the removal 

of the distressed slabs to the installation of the precast slabs were 

2.5 and 4.25 hours for undoweled and doweled sections, 

respectively. The problem of traffic control was encountered as 

no work was permitted for several periods of time. The plan was 

to evaluate the performance of the repairs under high-volume 

traffic. 

Speir et al. 2001 La Guardia Airport, 

New York 

A feasibility study was conducted to provide preliminary design 

details for two precast PCC slab construction options and an 

asphalt concrete approach. The precast options were 

• conventional plain jointed panels in two sizes (3.8 m by 3.8 m 

[12.5 ft by 12.5 ft] and 7.6 m by 7.6 m [25 ft by 25 ft]) and slab 

thicknesses ranging from 30.5 to 40.6 cm (12 in. to 16 in.). 

• posttensioning of multiple slab panels to provide an effective 

slab size of 7.6 m by 7.6 m (25 ft by 25 ft). 

The initial cost of the asphalt concrete option was found to be the 

lowest among the three construction approaches. However, based 

on a 40-year life cycle cost comparison, both precast approaches 

were found to be more cost effective. 

continued 
 6 

Source 

Location of 

Construction Summary of Findings 

Tyson 1976 Culpeper, Richmond, 

and Fredericksburg, 

Virginia 

Four full-depth pavement repair procedures were investigated, 

including rehabilitation by stress relief, cast-in-place restoration, 

precast replacement, and cast-in-place replacement. Elimination 

of curing time and potentially better concrete quality were 

emphasized as two major advantages of the precast procedure 

over the cast-in-place procedure. The main processes for the 

precast replacement procedure included precast slab fabrication, 

pavement removal, and precast slab installation. Since no dowel 

bars were used, the deflection test using the Benkelman beam was 

conducted. The results indicated that the precast slabs performed 

satisfactorily and had about three times smaller deflections than 

adjacent slabs. Three months after the construction, a precast slab 

was lifted to investigate the condition of the interface between the 

underlying mortar and the slab, which was found to be unbonded. 

It was recommended that the bedding mortar should have a slump 

exceeding 200 mm (8 in.) to provide uniform seating. 
 7 

CHAPTER 3. MICHIGAN FIELD STUDY 

SITE SELECTION 

The test sections for the Michigan field study are located along I-675 in Zilwaukee and M-25 in 

Port Austin. For the existing portland cement concrete (PCC) pavement, cross section structural 

details, traffic, and number of panels installed are summarized in Table 2. The site was selected 

in concert with the Michigan Department of Transportation's (MDOT’s) Bay and Cass City 

Transportation Service Center (TSC) personnel. 

Table 2. Summary of Precast Panel Test Sites 

Project 

Route 

Designation 

Joint 

Spacing 

Pavement

Thickness Base Type 

Annual Average 

Daily Traffic 

(commercial) 

No. of 

Panels 

Installed 

I-675 Principal arterial 21.6 m 

(71 ft) 

10,400 (5%) 8* 

M-25 Minor arterial 30.2 m 

(99 ft) 

225 mm 

(9 in.) 

Dense-graded 

select base 

900–4,000 (3–11%) 12 

*Nine panels were installed; however, panel 1 is a conventional full-depth repair, and panels 2–9 are precast 

panels. 

PRECAST PANEL MIXTURE DESIGN AND FABRICATION DETAILS 

The precast PCC panels were fabricated by the contractor and transported to the project site. The 

typical PCC mixture design for this study is summarized in Table 3. 

Table 3. Portland Cement Concrete Mixture Designs for the Precast Panels 

Mix Ingredients Design 

Cement 312 kg/m3 (526 lbs/yd3) 

Water 127 kg/m3 (212 lbs/yd3) 

Fine aggregate 810 kg/m3 (1,366 lbs/yd3) 

Coarse aggregate 10,908 kg/m3 (1,838 lbs/yd3) 

Air-entraining agents 0.59 ml/kg (0.9 fl oz/cwt) 

The contractor was responsible for documenting the fresh and hardened concrete properties. 

Typical PCC concrete properties are summarized in Table 4. The average 28-day compressive 

strength based on 18 specimens was 30 MPa (4,300 lbf/in2

). 

All panels were 1.8 m (6 ft) long, 3.7 m (12 ft) wide, and 250 mm (10 in.) thick. The precast 

panels were fitted with three dowel bars 38 mm (1.5 in.) in diameter, 450 mm (18 in.) long, and 

spaced at 300 mm (12 in.) on center along each wheelpath. Perimeter steel was included 

(#16 [#5] bars) to resist handling and transportation stresses. Steel mesh (10 mm [0.375 in.] in 
 8 

diameter placed at 150-mm [6-in.] intervals and held together with 6-mm [0.25-in.] ties) was 

placed at the panel mid depth to resist the potential of early-age cracking. The panels were wetcured for 7 days using wet burlap covers. The 20 precast panels were stockpiled at the ready-mix 

concrete supplier’s yard. Eight panels were installed at the I-675 site, and 12 were installed at the 

M-25 site. The typical structural details are illustrated in Figure 1. 

Figure 2 summarizes the sequence of the fabrication process followed by the contractor. The 

standard hardware for lifting the slabs is visible in the figure. Figure 2 also illustrates the location 

and placement of dowel bars and temperature steel. 

Table 4. Fresh and Hardened Property Results for the Portland Cement Concrete Mixture 

Test data from June 3, 2003. 

Time of Air Slump Conc Temp Air Temp Flex. Str.

Concrete casting (%) (in) (

0

F (0F) (psi)

A 43 hrs 533

B 43 hrs 544

C

D

Specimen ID Age

3:10 PM 6.5 2 72 67

Test data from June 6, 2003. 

Time of Air Slump Conc Temp Air Temp Flex. Str.

Concrete casting (%) (in) 0

F (0F) (psi)

A 66 hrs 644

B 66 hrs 688

C

D

Specimen ID Age

3:15 PM 7 2.75 72 75

Test data from June 10, 2003. 

Time of Air Slump Conc Temp Air Temp Flex. Str.

Concrete casting (%) (in) 0

F (0F) (psi)

A 48 hrs 644

B 48 hrs 622

C

D

Specimen ID Age

8:55 AM 7 2.75 73 62

Test data from June 12, 2003 

Time of Air Slump Conc Temp Air Temp Flex. Str.

Concrete casting (%) (in) (

0

F (0F) (psi)

A 93 hrs 800

B 93 hrs 733

C

D

Specimen ID Age

12:50 PM 6.5 3 73 65
 9 

Figure 1. Structural details of the doweled precast panel. 
 10 

 

a) Reinforcement and dowel bar placement in the formwork. 

 

b) Concrete placement for precast panels. c) Texturing of fresh concrete. 

d) Curing of precast slabs. 

Figure 2. Fabrication of the doweled precast panels. 
 11 

CONSTRUCTION SEQUENCE 

Prior to the removal of the candidate panels, a distress survey was conducted in accordance with 

the protocol laid out in the LTPP distress identification manual (FHWA 2003). Typical distresses 

observed during the survey included mid-panel transverse cracks with associated spalling and 

deteriorated joints with spalling and asphalt patch deterioration. Examples of the typical 

distresses are shown in Figure 3. During the field visit the distress information was recorded on a 

distress documentation form (a sample form is presented in Appendix A). 

 

a) Deteriorated joint with cold patch with spalling. b) Medium-severity transverse crack. 

 

c) High-severity transverse crack. d) Deteriorated joint with spalling. 

Figure 3. Typical distresses. 

The sequence of operations for offsite activities and onsite activities for the Michigan field study 

are listed below: 

Offsite Activities 

1. Fabrication of the precast panels. 

2. Storage of the fabricated precast panels. 

Onsite Activities 

1. Documentation of distresses. 

2. Identifying and marking of the repair boundary. 
 12 

3. Sawcutting panel boundaries and slab removal. 

4. Initial cleaning of the exposed base. 

5. Jackhammering of the dowel slots. 

6. Air cleaning and sandblasting of the dowel slots. 

7. Final cleaning and grade adjustment of the base. 

8. Placement of the leveling fill.* 

9. Installation of the precast panel. 

10. Adjustment of panel elevation with respect to the adjacent panels. 

11. Backfilling of the dowel slots. 

12. Sealing of joints. 

*Step 8 of the construction process does not exist if the precast panel grade 

adjustment is done using high-density polyurethane (HDP) foam. In that case, 

after final cleaning and grade adjustment of the base, the precast panel is placed 

and portholes for injecting the HDP are drilled. The slab elevation adjustment is 

achieved by injecting the HDP foam. 

Descriptions of the activities listed above are presented in the following section of the report. 

(The types of distresses addressed by the repair strategy and the panel fabrication process, 

illustrated in Figure 2, are presented above and will not be discussed further). 

Sawcutting Panel Boundaries and Removal 

The candidate repair sections were identified and marked by the MDOT personnel (Bay City and 

Cass City TSC). The slab boundaries were outlined by the contractor and sawcut. The limits of 

the pavement area to be removed were sawed in the transverse direction. Following the 

sawcutting operation, the lift hooks were inserted and the distressed slabs were removed using a 

front-end loader. During this process, the outlines for the dowel slots in the adjacent panels were 

also cut. This concrete was later carved out using pneumatic jackhammers. Figure 4 illustrates 

the slab sawing and removal process. 
 13 

 

a) Sawcutting the existing slab. b) The existing slab after sawcutting. 

c) Removing the existing slab. 

Figure 4. Sawcutting of slab boundaries and slab removal. 

Initial Base Preparation 

For all the panels the aggregate base was excavated 38–50 mm (1.5–2 in.) below the bottom of 

the existing slab to accommodate the thicker, 250-mm (10-in.) precast panel. At this point all 

concrete debris from the slab removal operation was removed. Dewatering of the base was not 

required at any of the project sites. Figure 5 illustrates the base preparation activity. 

Figure 5. Initial cleaning and preparation of the base. 
 14 

Preparation of Load Transfer Slots 

As shown in Figure 6, there are three dowel bars in each wheelpath. The dowel slot cutting and 

preparation include initial grooving to the required depth with a concrete saw; jackhammering of 

the concrete to carve out the dowel slot; air cleaning of dowel slot to remove debris and any 

loose concrete pieces; and sandblasting of the dowel slots. The dowel slots were approximately 

100 mm (4 in.) wide and 133 mm (5.25 in.) deep (base of the slot cut). Figure 6 illustrates the 

slot cutting and preparation process. 

 

 a) Jackhammering of dowel slots. b) Debris removal from dowel slots. 

 c) Sandblasting of dowel slots. d) Completed dowel slots. 

Figure 6. Preparation of the load transfer slots. 

The dowel slots were placed at 300 mm (12 in.) on center. The slots are 375 mm (15 in.) from 

the nearest longitudinal edge (shoulder or centerline). Figure 7 shows a schematic cross section 

of the dowel assembly. 
 15 

Figure 7. Schematic cross section of the dowel assembly. 

Final Grading and Installation of the Precast Panel 

This part of the installation process can be achieved by two different methods: slab grade adjustment 

using HDP foam or slab grade adjustment using flowable fill. 

Elevation Adjustment Using High-Density Polyurethane Foam 

Once the dowel slots were prepared and a final cleaning and grading of the base prepared the 

surface for receiving the precast panels, the precast panels were transported from the flat-bed 

truck to the excavation using a front-end loader. The HDP foam method of slab stabilization was 

used for 6 panels along the I-675 site and 10 panels along the M-25 site. Approximately 4–6 

holes (16 mm [0.625 in.] in diameter) were drilled per panel to inject the foam. The polyurethane 

foam is made from two liquid chemicals that combine under heat to form a strong, lightweight, 

foam-like substance. The chemical reaction between the two materials causes the foam to expand 

and fill the voids. According to the manufacturer’s specification, the HDP foam sets in 

approximately 15 minutes (approximately 90 percent of full compressive strength), and the 

precast panel is ready to carry load. For the purpose of slab stabilization, the foam density is 

about 64 kg/m3

 (4 lbs/ft3) with a compressive strength range of 414 to 1,000 kPa (60 to 

145 lbf/in2

). 

Once the slab elevations were verified and deemed acceptable, the dowel slots were grouted and 

the joints were sealed. Figure 8 illustrates the slab installation process. 

10 in.

18 in.

4 in. 51⁄2~6 in. 

Jackhammered and 

sandblasted dowel slot

11⁄2-in. dowel bar 

Existing pavement 

Precast slab

9 in. 

Dense graded 

aggregate base 

Flowable fill 

or HDP 
 16 

 

a) Panel installation. b) Panel installation and alignment. 

 

 c) Drilling of injection portholes. d) Stabilized slab. 

Figure 8. Precast panel installation and stabilization using high-density polyurethane foam. 

Elevation Adjustment Using Flowable Fill 

Two precast panels were stabilized at each of the test sites using flowable fill. The excavation 

was 38–50 mm (1.5–2 in.) below the bottom of the existing slab to accommodate the thicker 

250-mm (10-in.) precast panel. The flowable fill was transported to the project site in a readymix concrete truck and discharged directly into the excavation. Figure 9 illustrates the flowable 

placement and the backfilling of the dowel slots. The fill was leveled to a depth of 250 mm 

(10 in.) from the surface of the existing slab. The flowable fill mixture design includes 

1,020.6 kg (2,250 lb) of sand, 56.7 kg (125 lb) of cement, 136.1 kg (300 lb) of water, and 118 ml 

(4 fl oz) of air entraining admixture. The average 28-day compressive strength ranged from 1.0 to 

1.2 MPa (150–175 lbf/in2

). Once the slab elevations were verified and deemed acceptable, the 

dowel slots were grouted and the joints were sealed. 

After the slab was installed and leveled, the dowel slots were backfilled and transverse joints 

were sealed. 
 17 

 

 a) Placing of flowable fill. b) Leveling of flowable fill. 

 

 c) Back filling of dowel slots. 

 d) Back-filled dowel slots. e) Completed panel. 

Figure 9. Flowable fill operation and dowel slot backfilling. 
 18 

CONSTRUCTION PRODUCTIVITY 

The construction productivity metrics include the documentation of time to complete the 

installation of one panel, list of possible concurrent activities, various equipment used for the 

installation of the panels, and panel installation crew size. The detailed panel installation 

activities include the following: 

 Slab (existing) demolition—A1. 

o Sawcutting of the repair boundaries. 

o Sawcutting of dowel slot outlines in the adjacent panels. 

o Removal of distresses panel. 

 Initial cleaning of the exposed base layer—A2. 

o Removal of debris. 

o Dewatering (if needed). 

 Cutting (jackhammering) of dowel slots to specification depth—A3. 

 Final cleaning and cleaning of the exposed base—A4. 

 Air cleaning and sandblasting of the dowel slots—A5. 

 Placement of the precast panel and final alignment—A6. 

 Drill holes for the high-density polyurethane foam and inject foam to stabilize and level the 

slab—A7. 

 Grout dowel slots and lift hook holes—A8. 

 Seal joints and open to traffic—A9. 

Typical individual times, labor requirements, and equipment needed to execute the activities 

listed above are summarized in Table 5. Based on the proximity of the candidate panels to each 

other, construction activities A2–A7 can be performed somewhat concurrently, resulting in 

increased productivity. 

Table 5. Typical Construction Time, Labor, and Equipment Needs 

Activity 

Code 

Time, 

minutes Recommended Equipment (labor needs) 

A1 60 Concrete saw (1), front-end loader (1 operator) 

A2 5 Nothing specific (2) 

A3 20 Pneumatic jackhammers (2) 

A4 15 Plate compactor (1) 

A5 21 Sandblasting equipment (2) 

A6 20 Front-end loader (1 operator, 3 additional to guide the alignment) 

A7 25 Drills and high-density polyurethane injection equipment (2) 

A8 26 Grout mixer (2) 
 19 

Construction Activities—I-675 

For the I-675 project, all nine panels were installed in 1 day under the same traffic control due to 

the close proximity of the panels. Figure 10 illustrates the relative location of the precast panels. 

Figure 11 illustrates the timeline (typical) for the installation of panel 5. 

Figure 10. Relative distances of patches along the I-675 project. 

Figure 11. Construction timeline for panel 5. 

189’ 7” 1664’ 3” 67 162’ 231’ 269’ 478 571’ 9”

1 2 3 4 5 6 7 8 9

Conventional fulldepth repair 

Stabilized using 

flowable fill 
 20 

The total time required to install the panel was less than 120 minutes. The two most timeconsuming activities were the preparation of the dowel slots and adjustment of the panel 

elevation with respect to the existing concrete pavement. The dowel slot-cutting time can be 

shortened by reducing the dimensions of the slots. 

Patch 1 in this project had to be converted to a conventional cast-in-place, full-depth repair 

because the pavement at this location was superelevated and the precast panel dimensions were 

such that the resulting joint openings would have been unacceptable. In the future, such issues 

can be resolved if the contractor makes exact measurements of the panels to be replaced. This 

measurement data can then be used during the manufacturing of the panels. Therefore, this panel 

will serve as the control. The performance of the precast panels (2 through 9) will be compared 

with that of panel 1. Also, panels 5 and 6 were stabilized using flowable fill, whereas as the other 

precast panels were stabilized using the HDP foam. The impact of these two methods of slab 

stabilization on panel performance will be monitored and evaluated over the next 2 years as part 

of this study. 

Construction Activities—M-25 

At the M-25 project site, 12 precast panels were installed over a period of 3 days. Contributing to 

the longer installation time were the distances between some of the panels and the construction 

interruptions due to rain. Figure 12 illustrates the relative location of the precast panels. 

Figure 12. Relative distances of patches along the M-25 project. 

Figure 13 illustrates the contruction timeline for panels 2 and 3. Due to the close proximity of 

these panels, some of the construction activities overlap. Panels 2 and 3 were stabilized using 

flowable fill, and the remaining panels were stabilized using HDP foam. 

Stabilized using flowable fill 
 21 

Figure 13. Construction timeline for patches 2 and 3. 

REPAIR EFFECTIVENESS OF THE PRECAST PANELS 

The repair effectiveness of the panels was determined by conducting distress surveys and fallingweight deflectometer (FWD) tests according to the protocol illustrated in Figure 14. Test 

locations 1 through 8 allowed for the computation of load transfer efficiency (LTE) across the 

approach and leave joints. The LTE was computed using the following equation, where LTE: 

( ) = ×100

L

% u LTE

δ

δ

δ

 

 

 

Approach joint 

Leave joint 

Outer wheel path 

Traffic direction 

Mid slab 

1 2 3 4

5 6 7 8

Inner wheel path

Figure 14. Falling-weight deflectometer test locations to evaluate panel effectiveness. 
 22 

Field evaluations of the precast panels were conducted in October 2003, May 2004, October 

2004, and May 2005. 

Field Evaluation Results 

I-675 Test Site 

The FWD results are presented in Figure 15, in charts (a) through (c). The dashed lines in the 

charts represent the minimum LTE threshold of 70 percent and a deflection ratio threshold of 3 

for doweled joints. On average, the approach and leave LTEs are in excess of 70 percent (the 

average LTEs range from 61 percent to 90 percent) as shown in Figure 15 (a) and (b) and in 

Table 6. Figure 15 (c) represents the relative deflections (peak) of the joint with respect to the 

mid-slab deflection (peak). The approach joint deflection ratios range from 1.2 to 2.1, whereas, 

the leave joint ratios range from 1.3 to 2.3, indicating an acceptable support under the panel. 

Table 7 displays and summarizes the condition of the precast panels as of September 2005. The 

performance evaluation was conducted by MDOT. Panel 2 exhibited premature cracking along 

the leave joint; the remaining seven panels exhibited acceptable behavior at the time of the last 

performance evaluation. 

For panel 2, the average before-leave joint LTE (%) ranges from 63 to 75 whereas the after-leave 

joint LTE (%) ranges from 68 to 91. The type of distress observed in panel 2 looks like failure at 

the end of the dowels due to thermal movement of the pavement. The hot pour joint sealant is 

pushed up in the joint, indicating the pavement closing up on the leave side of the joint. Uniform 

restraint was not provided in the reservoir opening between the dowels, which may have resulted 

in high bearing stresses at the dowel ends. Another reason for this premature joint failure could 

be that the dowels along the leave joint were horizontally skewed as a result of the installation. 

This skewing could have resulted in “locking” of the joint and impeding joint movement under 

environmental and traffic loads. 
 23 

0

10

20

30

40

50

60

70

80

90

100

123456789

Patch ID

Average LTE (%)

OWP Leave (BJT) OWP Leave (AJT)

IWP Leave (BJT) IWP Leave (AJT)

 (a) Leave slab loading. 

0

10

20

30

40

50

60

70

80

90

100

123456789

Patch ID

Average LTE (%)

OWP Approach (BJT) OWP Approach (AJT)

IWP Approach (BJT) IWP Approach (AJT)

 (b) Approach slab loading. 

0

1

2

3

4

5

123456789

Patch ID

Deflection Ratio

OWP Approach (AJT) OWP Leave (BJT)

IWP Approach (AJT) IWP Leave (BJT)

 (c) Deflection ratio. 

Figure 15. Average load transfer efficiencies and deflection ratios for the I-675 test site. 
 24 

Table 6. Summary of Approach and Leave Joint Load Transfer Efficiencies (LTEs), I-675

Panel Number 

Average Approach 

Joint LTE (%) 

Average Leave 

Joint LTE (%) 

1 89.1 81.6 

2 74.5 74.7 

3 78.6 74.4 

4 78.0 82.0 

5 72.0 80.5 

6 72.0 61.3 

7 78.6 78.0 

8 83.4 72.5 

9 84.3 77.0 

Table 7. Summary of Panel Performance, I-675 (Survey Date: 9/14/05) 

Precast Panel ID Performance Description 

Panel 1 

There is no evidence of distress. The average LTE 

ranges from 81% to 89%, and the deflection ratios 

are less than 2.5. 

continued 
 25 

Table 7. Summary of Panel Performance, I-675 (Survey Date: 9/14/05) (continued) 

Precast Panel ID Performance Description 

Panel 2 

Panel cracking observed in the vicinity of the dowel 

bars. The average joint LTE is 74.5%, and the 

deflection ratios are less than 2. 

Panel 3

Panel in good condition. Some spalling was 

observed along the joint. The average joint LTE 

ranges between 75% and 78%, and the deflection 

ratios are less than 2. 

Panel 4

The panel is in good condition. The average joint 

LTE ranges between 78% to 82%, and the deflection 

ratios are less than 2. 

continued 
 26 

Table 7. Summary of Panel Performance, I-675 (Survey Date: 9/14/05) (continued) 

Precast Panel ID Performance Description 

Panel 5 

The panel is in good condition. The average joint 

LTE ranges between 73% to 80%, and the 

deflection ratios are less than 2. The panel was 

stabilized using flowable fill. 

Panel 6 

Panel is in acceptable condition. Some spalling of 

the dowel slot back-fill was observed. The average 

joint LTE ranges between 61% and 70%, and the 

deflection ratios are less than 2. The panel was 

stabilized using flowable fill. 

Panel 7 

The panel is in good condition. A high spot was 

observed at the leading edge of the repair. The 

average joint LTE 78%, and the deflection ratios 

are less than 2. 

continued
 27 

Table 7. Summary of Panel Performance, I-675 (Survey Date: 9/14/05) (continued) 

Precast Panel ID Performance Description 

Panel 8 

The panel is in good condition. The average joint 

LTE ranges from 73% to 80%, and the deflection 

ratios are less than 2. 

Panel 9 

The panel is in good condition. A high spot was 

observed at one end of the repair. The average joint 

LTE ranges from 77% to 84%, and the deflection 

ratios are less than 2. 

M-25 Test Site 

The FWD results are presented in Figure 16 (a) through (c). The dashed lines represent the 

minimum LTE threshold of 70 percent and a deflection ratio threshold of 3 for doweled joints. 

On average, the approach and leave LTEs are in excess of 70 percent (the average LTEs range 

from 72 percent to 90 percent) as shown in Figure 16 (a) and (b) and Table 8. Figure 16 (c) 

represents the relative deflections (peak) of the joint with respect to the mid-slab deflection 

(peak). The approach joint deflection ratios range from 1.2 to 2.3, whereas the leave joint ratios 

range from 1.0 to 3.0, indicating an acceptable support under the panel. 
 28 

0

10

20

30

40

50

60

70

80

90

100

1 2 3 4 5 6 7 8 9 10 11 12

Patch ID

Average LTE (%) .

OWP Leave (BJT) OWP Leave (AJT)

IWP Leave (BJT) IWP Leave (AJT)

 (a) Leave slab loading. 

0

10

20

30

40

50

60

70

80

90

100

1 2 3 4 5 6 7 8 9 10 11 12

Patch ID

Average LTE (%) .

OWP Approach (BJT) OWP Approach (AJT)

IWP Approach (BJT) IWP Approach (AJT)

 (b) Approach slab loading. 

0

1

2

3

4

5

1 2 3 4 5 6 7 8 9 10 11 12

Patch ID

Deflection Ratio .

OWP Approach (AJT) OWP Leave (BJT)

IWP Approach (AJT) IWP Leave (BJT)

 (c) Deflection ratio. 

Figure 16. Average load transfer efficiencies and deflection ratios for the M-25 test site. 
 29 

Table 8. Summary of Approach and Leave Joint Load Transfer Efficiencies (LTE) 

Panel 

Number 

Average Approach 

Joint LTE (%) 

Average Leave 

Joint LTE (%) 

1 85.0 82.0 

2 90.2 88.3 

3 88.0 82.2 

4 78.5 73.8 

5 87.8 82.4 

6 87.9 87.9 

7 87.5 85.8 

8 86.9 87.8 

9 89.1 72.6 

10 84.6 89.7 

11 89.4 90.3 

12 88.0 62.0 

Table 9 summarizes (by way of photographs) the condition of the precast panels in September 

2005. The performance evaluation was conducted by MDOT. Of the 12 panels, 10 exhibited 

acceptable to good behavior at the time of the last performance evaluation. 

Figure 17 summarizes the structural response of the leave and approach joints for panels 4 and 9. 

It is evident that for both panels there was a significant drop in leave joint efficiencies from 

October 2003 and May 2004. The plot also shows that there is also a significant loss in relative 

support along the distressed joint during the same time frame. During the summer of 2004 the 

thumb area of Michigan experienced a series of 32 o

C (90 oF) days that may have resulted in 

“abnormal” expansion of the pavement slabs. Such expansion could have resulted in a joint 

blowout. A possible contributor to joint blowout is horizontal misalignment of dowel bars. If 

such misalignment occurred during installation of the panels, the joint may not have been 

flexible enough to accommodate slab expansion caused by the high ambient temperatures. Figure 

18 illustrates how dowel misalignment could reduce joint flexibility. 

The finite element model EverFE (Davids 2003) was used to approximate the effects of 

horizontal skew and high ambient temperatures on the tensile stresses on the precast concrete 

panel and vertical shear stresses in the dowel bars. Three variables were included in this limited 

analysis: 

 Dowel horizontal skew angles: - 0, 3, 6, and 10 degrees. 

 Temperature differential (maximum ambient–construction): -37 o

C (-35 oF) and 

16 o

C (60 oF). 

 Axial friction force: - 0, 45, 445, 4,448, 44,482 kN (- 0, 10,000, 100,000, 

1,000,000, 10,000,000 lbf). 

Figure 19 summarizes the findings of the analysis. 
 30 

Table 9. Summary of Panel Performance, M-25 (Survey Date: 9/14/05)

Precast Panel ID Performance Description 

Panel 1 

The panel is in good condition. The average joint LTE 

ranges from 82% to 85% and the deflection ratios are 

less than 2. 

Panel 2 

The panel is in good condition. The average joint LTE 

ranges from 88% to 92% and the deflection ratios are 

less than 2. The panel was stabilized using flowable 

fill. 

Panel 3 

The panel is in good condition. The average joint LTE 

ranges from 82% to 88% and the deflection ratios are 

less than 2. The panel was stabilized using flowable 

fill. 

continued 
 31 

Table 9. Summary of Panel Performance, M-25 (Survey Date: 9/14/05) (continued)

Precast Panel ID Performance Description 

Panel 4 

The repair is severely deteriorated. The cracking along 

the dowels was first observed during the summer of 

2004. The cracking was observed along the approach 

and leave joint of the panel. The average joint LTE 

ranges from 73% to 78% and the deflection ratios are 

less than 2. 

Panel 5 

The panel is in good condition. The average joint LTE 

ranges from 82% to 88% and the deflection ratios are 

less than 2. 

Panel 6 

The panel is in good condition. The average joint LTE 

is 88% and the deflection ratios are less than 2.5. 

continued 
 32 

Table 9. Summary of Panel Performance, M-25 (Survey Date: 9/14/05) (continued)

Precast Panel ID Performance Description 

Panel 7 

The panel is broken in one corner most probably due 

to snowplow damage, as there was a high spot along 

the approach joint. The average joint LTE ranges from 

86% to 88% and the deflection ratios are less than 2. 

Panel 8 

The panel is in good condition. The average joint LTE 

is 87% and the deflection ratios are less than 2. 

Panel 9 

The repair is deteriorated. The cracking along the 

dowels was first observed during the summer of 2004. 

The cracking is along the leave joint of the panel. The 

average joint LTE ranges from 72% (leave joint of the 

panel) to 89% and the deflection ratios are 

approaching 3 along the leave joint of the panel. 

continued 
 33 

Table 9. Summary of Panel Performance, M-25 (Survey Date: 9/14/05) (continued) 

Precast Panel ID Performance Description 

Panel 10 

The panel is in good condition. The average joint LTE 

ranges from 85% to 90% and the deflection ratios are 

less than 2.5. 

Panel 11 

The panel is in good condition. The average joint LTE 

is 90% and the deflection ratios are less than 2. 

Panel 12 

The panel is in acceptable condition. Trailing edge 

(leave joint of the panel) broken in the old concrete. 

The average joint LTE ranges from 62% (leave joint) 

to 88% and the deflection ratios are less than 2.5. 

However, the deflection ratio at the broken edge is 

approaching 3. 
 34 

0.0

25.0

50.0

75.0

100.0

October 2003 May 2004 October 2004

FWD Testing Date

LTE

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

Deflection Ratio

LTE-Panel 4 LTE-Panel 9 LTE-Others

DR-Panel 4 DR-Panel 9 DR-Others

(a) Leave Joint 

0.0

25.0

50.0

75.0

100.0

October 2003 May 2004 October 2004

FWD Testing Date

LTE

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

Deflection Ratio

LTE-Panel 4 LTE-Panel 9 LTE-Others

DR-Panel 4 DR-Panel 9 DR-Others

 (b) Approach Joint 

Figure 17. Structural response of panels 4 and 9. 
 35 

Uneven joint 

opening 

Horizontal skew 

in dowels 

Pre-cast Panel 

Figure 18. Line sketch illustrating the possible dowel skew and uneven joint opening. 

0

20

40

60

80

100

120

140

0 2000 4000 6000 8000 10000 12000

Axial Friction, kips

Max. Princ. Stress., psi

0-deg, T=35 3-deg, T=35 6-deg, T=35 10-deg, T=35

0-deg, T=60 3-deg, T=60 6-deg, T=60 10-deg, T=60

(a) Effect of temperature differential on concrete tensile stresses. 

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 2000 4000 6000 8000 10000 12000

Axial Friction, kips

Max. Shear, kips

0-deg 3-deg 6-deg 10-deg

0-deg, T=60 3-deg, T=60 6-deg, T=60 10-deg, T=60

(b) Effect of horizontal dowel skewness on dowel vertical shear force. 

Figure 19. Results of the finite element analysis. 
 36 

RECOMMENDATIONS FOR PRECAST PANEL INSTALLATION 

Based on the experience of the Michigan field trials, the following practices are recommended 

for future precast panel installations for full-depth repair of jointed concrete pavements: 

1. Provide an expansion cap at one end of the dowel bar to accommodate slab 

movement due to environmental loading and to prevent closing of the joint. 

2. Provide expansion material along the joint to accommodate joint movement due 

to thermal expansion and contraction. 

3. Diamond grinding of the panel, especially the joints, is recommended to remove 

high spots. These high spots have a potential to “break off” as a result of 

snowplowing operations. 

4. The width of the dowel slot should be kept as small as possible to accommodate 

the dowel bar. This will reduce construction time and also reduce the potential for 

dowel skewing in the horizontal plane. 

5. Care needs to be given to sawing the existing concrete for the outline of the patch. 

The saw cuts should be perpendicular to the centerline to avoid skewing the patch 

when it is placed (which leads to problems with the dowel bars locking in the 

slots). 

6. To reduce construction time, multitasking during the installation process should 

be encouraged whenever possible. Construction and installation time can be 

positively impacted if the repair locations are close to each other, allowing for the 

installation of multiple panels under one traffic control setup. 
 37 

CHAPTER 4. COLORADO FIELD STUDY 

SITE SELECTION 

Along the I-25 corridor north of Denver, 143 concrete slabs were replaced at 18 separate 

locations between Mead and Loveland (mileposts 244 to 270). The candidate sections were 

selected by the Colorado Department of Transportation (CDOT) maintenance crews. Due to 

large volumes of traffic, single-lane closures were permitted for construction for an 8-hour 

period between 9 p.m. and 5 a.m. Additionally, the construction areas were required to be open 

to unimpeded traffic during the higher volume times. Table 10 summarizes the locations of the 

143 panels along I-25 between Mead and Loveland. 

Table 10. Panel Location Summary Along the I-25 Corridor 

Location 

Location 

No. 

Milepost and 

 (Direction) 

No. of Panels 

Installed 

Panel Thickness, 

mm (in.) 

1 244.41 (NB) 12 185 (7.25) 

2 244.83 (SB) 8 160 (6.25) 

3 244.90 (SB) 10 185 (7.25) 

4 244.96 (SB) 2 185 (7.25) 

5 245.19 (SB) 4 160 (6.25) 

6 245.45 (NB) 3 185 (7.25) 

7 245.46 (NB) 3 185 (7.25) 

8 247.46 (SB) 4 160 (6.25) 

9 247.68 (NB) 13 160 (6.25) 

Mead 

10 249.41 (SB) 4 160 (6.25) 

1 256.41 (SB) 13 140 (5.5) 

2 256.49 (SB) 8 160 (6.25) 

3 257.46 (SB) 16 160 (6.25) 

4 257.99 (SB) 15 160 (6.25) 

5 258.02 (NB) 5 160 (6.25) 

6 258.12 (NB) 5 160 (6.25) 

7 258.14 (SB) 14 140 (5.5) 

8 269.84 (NB) 5 Cast-in-place 

Loveland 

Added work 258.72 (SB) 13 160 (6.25) 

The average annual average daily traffic (AADT) and percentage of trucks along the 

construction corridor were 45,886 and 14 percent respectively based on year 2002 data. The 

contractor was responsible for making all the measurements prior to the fabrication of the panels. 

The measurements were made along the four sides and diagonals to account for any joint 

skewing. Multiple pavement cores were extracted at each location to determine variations in 

thickness from end to end as well as near the shoulder and centerline. The dimensional 

information was used in customizing the precast panel fabrication. 
 38 

PRECAST PANEL MIXTURE DESIGN AND FABRICATION DETAILS 

The precast PCC panels were fabricated by the contractor and transported to the project site. The 

typical structural details of the precast panels are illustrated in Figure 20. The tie bar slots, which 

were formed during the panel fabrication process, were placed at 0.91 m (3 ft) on center. The 

panel also consists of #4 or #5 steel depending on the panel thickness. The panel lengths were 

variable so as to match the contraction joint spacing. The typical PCC mixture designs for this 

study are summarized in Table 11, and the compressive strength data for the Mead and Loveland 

sites are summarized in Table 12. 

Varies 12 ’-20 ’

3’-0”

3’-0”

3’-0”

3’-0”

Pick up point

#4 @ 1 ’-2” for 6 ” thick panels

#5 @ 1 ’-0” for 7 ” thick panels

Varies 12 ’-20 ’

3’-0”

3’-0”

3’-0”

3’-0”

Pick up point

#4 @ 1 ’-2” for 6 ” thick panels

#5 @ 1 ’-0” for 7 ” thick panels

Figure 20. Structural details of the precast panel. 

Table 11. Portland Cement Concrete Mixture Designs for the Precast Panels 

Mix Ingredients Design, lbs/yd3

Cement 390.4 kg/m3 (658 lbs/yd3) 

Water 128.7 kg/m3 (217 lbs/yd3) 

Fine aggregate 811.6 kg/m3 (1,368 lbs/yd3) 

Coarse aggregate 933.8 kg/m3 (1,574 lbs/yd3) 

Air-entraining admixture 38.7 ml/m3 (1.0 fl.oz/yd3) 

Water-reducing admixture 8.158 kg/m3 (220 oz/yd3) 

High-range water reducer 1.854 kg/m3 (50 oz/yd3) 

Nonchloride accelerator 10.753 kg/m3 (290 oz/yd3) 
 39 

Table 12. Compressive Strength of Concrete From the Mead and Loveland Sites 

 Average Compressive Strength Data, MPa (lbf/in2) 

Location <24 hours 7 days 28 days 

1 (Loveland) 19.3 (2,805) 28.5 (4,135) – – 

3 (Loveland) 20.4 (2,960) 29.2 (4,240) 35.6 (5,160) 

7 (Loveland) 18.4 (2,665) 29.4 (4,265) – – 

1 (Mead) 24.7 (3,585) 32.4 (4,705) 37.9 (5,490) 

3 (Mead) 24.9 (3,615) 29.4 (4,270) 35.2 (5,100) 

7 (Mead) 21.4 (3,105) 35.1 (5,085) 43.0 (6,240) 

9 (Mead, slabs 1–3) 20.9 (3,025) 34.2 (4,965) 40.3 (5,840) 

9 (Mead, slabs 4–6) 23.9 (3,450) 38.2 (5,545) 46.2 (6,700) 

9 (Mead, slabs 7–9) 23.4 (3,395) 37.6 (5,450) 42.5 (6,170) 

CONSTRUCTION SEQUENCE 

Prior to the removal of the candidate panels a distress survey was conducted. Typical distresses 

observed during the survey included midpanel transverse cracks with associated spalling; joint 

sealant damage, spalling, and asphalt patch deterioration; and corner cracking. Some examples of 

distresses are shown in Figure 21. 

 

Figure 21. Examples of distresses. 

The sequences of operation for offsite and onsite activities in the Colorado field study are listed 

below: 

Offsite Activities 

1. Fabrication of the precast panels. 

2. Storage of the fabricated precast panels. 
 40 

Onsite Activities 

The onsite activities were divided into four construction operations: 

1. Slab removal and base preparation: 

a. Sawcutting of panel boundaries. 

b. Demolition of distressed panels. 

c. Removal of the distressed panels. 

d. Cleaning of the exposed base. 

e. Heat-lancing the exposed concrete faces to remove traces of moisture. 

2. Precast panel placement and alignment: 

a. Transporting precast panels from the storage yard. 

b. Placement of the precast panels into the prepared excavation. 

3. Precast panel elevation adjustment: 

a. Drilling of injection portholes. 

b. Injection of HDP foam to adjust slab elevation. 

c. Filling of voids (if any) with HDP foam to ensure uniform support under the panel. 

4. Joint preparation: 

a. Sawcutting of tie slots in the existing end panels to match with the slots in the precast 

panels. 

b. Removal of all extra foam that surfaced during the slab stabilization and void filling 

process. 

c. Air-cleaning and sandblasting all tie slots to ensure good bonding. 

d. Heat lance the tie slots to remove all traces of moisture. 

e. Insert the fiberglass tie bars. 

f. Backfill tie slots with prewashed dried aggregate. 

g. Apply the polyurethane joint bonding material. 

h. Seal injection ports using nonshrink grout. 

The steps in a typical precast panel installation process in the field include are described below. 

Slab Demolition and Removal 

The perimeter of each of the distressed panel was sawcut. Additional transverse cuts were made 

to expedite the panel-breaking operation. The initial breaking of the concrete was done using a 

standard backhoe fitted with a jackhammer. An additional track-hoe was used to excavate and 

remove the demolished concrete. Figure 22 illustrates the slab demolition and removal process. 

Base Cleaning and Preparation 

The exposed base was swept and cleaned using compressed air. In addtion to the cleaning, the 

base and joint edges were dried (to remove any traces of moisture) using a hot-air lance. A 

secondary effect of using the hot-air lance was to expedite the curing of the slab-jacking foam. 

Figure 23 illustrates the base preparation activities. 
 41 

 

a) Slab demolition b) Removal of debris 

Figure 22. Slab demolition process. 

Figure 23. Base preparation activities. 

Panel Placement and Alignment 

Panel Placement 

The panels were brought to the site on a flatbed truck and lowered into the excavation using a 

133-kN (30-kip), truck-mounted crane. Figure 24 illustrates the panel placement process. 
 42 

 a) Panel moved from flatbed truck. 

 

 b) Panel lowered into excavation. c) Alignment of panel. 

Figure 24. Panel placement process. 

Panel Alignment 

The precast panel elevations prior to jacking ranged from 0 to 75 mm (0–3 in.) below the passing 

lane or shoulder. A two-part polymer (486 Star) was mixed and simultaneously injected through 

the portholes 16 mm (0.625 in.) diameter to lift the precast panel. The polyurethane foam has a 

free-rise density of 48.1–51.3 kg/m3

 (3.0–3.2 lbs/ft3), with a minimum compressive strength of 

6.89 kPa (40 lbf/in2) (ASTM 1621). According to the manufacturer specification the foam is 

expected to reach 90 percent of full compressive strength within 15 minutes. Dial indicators were 

mounted on the panel surface to monitor the change in the slab elevation relative to the adjacent 

pavement. The panel jacking commenced by lifting at the two corners on one side of the panel, 

followed by lifting of the slab at the other end, until the elevation was matched with the existing 

roadway. In addition, the foam also served to fill in voids under the panel after the slab jacking 

was completed. Uniform support under the panel is essential for good long-term performance. 
 43 

Joint Stitching and Bonding 

A good bonding surface was obtained by removing all the excess foam from the joint faces and 

formed stitch slots. This was accomplished by using a pavement saw to cut the foam on both 

sides of the construction joints. The joint faces were then sandblasted to ensure clean bonding 

surfaces. In addition to this the surfaces were hot-air-lanced to remove all traces of moisture. 

Stitch slots were saw cut in the existing approach and departure slabs. The entire sawcutting was 

done in the absence of water to prevent reaction with the slab-jacking foam and joint-bonding 

material (URETEK 600). 

The fiberglass stitches were placed into the 19-mm (0.75-in.) slot using two guide wire spacers, 

one at each end. The fiberglass ties are 0.9 m long, 127 mm wide, and 6 mm thick (36 in. long, 5 

in. wide, and 0.25 in. thick). A picture of the tie bar is shown in Figure 25. 

 

Figure 25. Fiberglass stitches. 

Table 13 summarizes the mechanical properties of the fiberglass stitches. This information was 

obtained from URETEK USA. The mechanical properties characterization was conducted by 

Wiss Janney and Elstner Associates, Inc. 

Table 13. Mechanical Properties of the Fiberglass Stitch 

Test Property Measured Data 

Ultimate load 9.689 kg (21,360 lb) 

Relative joint displacement (at ultimate load) (0.17 in. [0.01 in. at 8,000 lb]) 

Load at first softening 5.669 kg (12,500 lb) 

Ultimate average stiffness 56,925.842 kg (125,500 lb/in.) 

Dried aggregate (3–6 mm [0.125–0.25 in.]) was used to backfill the stitch slots, and polyurethane 

foam was applied to bind the aggregates together. 
 44 

The contractor also recommended that expansion joints be placed at intervals of 13.7–18.3 m 

(45–60 ft). The expansion joints were 19 mm (0.75 in.) wide and stitched together using the 

fiberglass ties. The joint consisted of a backer rod placed vertically at the longitudinal joint and 

stitches to isolate the polyurethane foam. The joint was then filled to approximately 50 mm 

(2 in.) from the top of the pavement with ground rubber, followed by a 13 mm (0.5 in.) bead of 

self-leveling silicone joint sealant. 

The injection ports were sealed using a nonshrink grout. The procedure included drilling out 

leftover jacking foam; cleaning the surface of the concrete for proper adhesion; and placing the 

grout. Figure 26 illustrates a cluster of completed panels. 

Figure 26. Completed cluster of panels. 

CONSTRUCTION PRODUCTIVITY 

The construction productivity metrics include documentation of the following: 

• Time to complete the installation of one cluster of panels. 

• List of possible concurrent activities. 

• Panel installation equipment used. 

• Panel installation crew size. 

Table 14 lists the equipment needed to successfully install the precast panels. The approximate 

construction completion time for all the panel clusters is provided in Table 15. 
 45 

Table 14. Equipment Used for Panel Installation 

Equipment Type Application in the Installation Process 

Ingersoll L6 light plant Work area lighting during night closures 

CAT 416 back-hoe with jackhammer Initial break up of concrete to be removed 

CAT 325B track-hoe Excavation of concrete to be removed 

Two haul trucks Haul concrete debris 

Ingersoll 185 compressor To remove debris from work area. Clean joints and stitch slots 

Two pavement saws To cut stitch slots in adjacent pavement slabs 

Sandblasting equipment To prepare joints and stitch slots 

Hot-air lance To prepare joints prior to bonding 

Propane weed burner To dry and heat aggregates used in the joint bonding operation 

Portable concrete mixture For aggregate mixing. Also used for mixing cement mortar for backfilling 

Figure 27 shows the relationship between average elapsed time (start to finish) per panel (within 

a cluster) and number of panels in a given cluster. From this plot it can be surmised that as the 

cluster size increases the installation productivity improves. Figure 28 highlights the contractor’s 

improving comfort level (in terms of production efficiency) with project progression. During the 

initial stages of the project the contractor was installing clusters with only one to two precast 

panels over a 9-hour construction window. After day 20, the production rate increased to four to 

eight precast panels per cluster. The increased productivity was a result of multitasking activities. 

Specific changes in the mode of operation made by the contractor included reduction in panel 

demolition time for the entire cluster of slabs; concurrence in the panel demolition, base 

preparation activity, and installation of new panels; and providing an additional applicator for 

joint bonding operations. The advantages of incorporating concurrent activities in the 

construction regime are illustrated in Figure 29. As the percentage (based on overall time per 

panel) of multitasking increases, the number of panels that can be installed within the allowable 

construction window increases.
 46 

Table 15. Approximate Installation Time for Patches (hours:minutes) 

Day Location/Panel No. Number of Panels Panel Excavation Panel Placement Panel Jacking Joint-Stitch Prep. Joint Bonding

13 M6, 1~3 3 1:39 1:12 1:27 1:29 1:15

14 M7, 1~3 3 1:42 0:49 1:38 1:55 1:18

15 M3, 18~16 3 1:02 0:23 1:59 1:40 1:05

16 M3, 11~10 2 1:49 0:08 0:40 1:35 1:10

17 M9, 1~4 4 1:18 0:37 0:53 2:20 2:38

18 M9, 5~8 4 1:26 0:25 1:15 1:31 1:39

19 M9, 9~13 5 1:32 0:19 1:18 0:53 3:12

20 M3, 15~12 4 1:31 0:21 0:54 2:28 2:22

21 M2, 8~5 4 1:06 1:12 2:34 N/A 2:29

22 M4, 20~19 2 1:02 0:11 N/A N/A N/A

22 M3, 9 1 N/A N/A 0:20 N/A N/A

23

24 M5, 24~21 4 1:31 0:25 N/A N/A 2:30

25 M2, 4~1 4 1:20 0:57 1:47 N/A 2:14

26 M1, 9~12 4 1:38 0:28 N/A 3:02 2:20

27 M1, 5~8 4 1:36 0:19 1:42 N/A 1:26

28 M1, 1~4 4 1:38 0:45 N/A N/A 1:10

29 L5, 1~5 5 1:28 0:32 1:43 N/A 1:55

30 L6, 1~5 5 1:34 0:39 1:20 N/A 2:35

31 M10, 1~4 4 2:19 N/A N/A N/A N/A

32 M8, 1~4 4 1:50 0:38 1:41 N/A 2:21

33 L4, 10~14 6 N/A 0:51 1:58 N/A 2:15

34 L4, 9~2 8 N/A 2:00 2:35 N/A 2:25

35 L4, 1 1 0:37 0:10 N/A N/A N/A

35 L3 4 N/A N/A 3:30 N/A N/A

36 L3, 5~10 6 2:03 0:44 1:56 N/A 2:20

37 L3, 11~16 6 N/A N/A 2:03 N/A 1:40

38 L2, 1~8 8 2:15 1:30 N/A N/A 2:10

39

40

41 L7, 1~7 7 N/A N/A N/A N/A N/A

42 L7, 8~14 6 N/A N/A 3:57 N/A 3:12

43 L1, 1~6 6 N/A N/A 3:03 N/A N/A

44 L1, 7~13 7 N/A 1:00 N/A N/A N/A

50 L7, 14 1 N/A 0:05 N/A N/A 0:33

51 E.P., 1~5 5 1:40 0:39 1:15 N/A 2:38

52 E.P., 6~9 4 N/A 0:41 1:13 N/A 1:03

53 E.P., 10~13 4 2:02 0:48 1:15 N/A 1:04

Night of saw cutting only

Surface grinding and repairs only

Surface grinding and repairs only
 47 

0

50

100

150

200

250

300

12345678

Number of Panels in a cluster

Average elapsed time per panel, min.

n=2

n=1

n=3

n=13

n=4

n=4

n=1 n=2

"n" indicates number of replicates

Figure 27. Relationship between average elapsed time per panel and the number of panels. 

0

50

100

150

200

250

300

0 10 20 30 40 50 60

Operation day

Average elapsed time per panel, min.

1-panel operation 2-panel operation 3-panel operation 4-panel operation

5-panel operation 6-panel operation 7-panel operation 8-panel operation

Figure 28. Illustration of improvement in operators’ comfort level. 
 48 

Day 15, 3-Panel Operation, 135 min./panel

9%

91%

One-Activitity Multi-tasking No-Activity

Day 16, 2-Panel Operation, 172 min./panel

94%

6%

Day 17, 4-Panel Operation, 103 min./panel

80%

3%

17%

Figure 29. Illustration of advantages of incorporating concurrent activities. 

REPAIR EFFECTIVENESS OF THE PRECAST PANELS 

One cycle of performance evaluation has been conducted at the Colorado sites since the 

inception of the project. The performance evaluation consisted of falling-weight deflectometer 

(FWD) testing and documenting the initiation (if any) of distresses. During June 2004, 81 precast 

panels along I-25 between Loveland and Mead were tested. Testing was conducted between 

9 p.m. and 5 a.m. Data from positions 1 and 3 were collected to monitor joint deflection. Position 

2 deflection data were used to monitor edge support, whereas deflection data from position 4 

provided information about midpanel support. The FWD testing and distress surveys were done 

concurrently. The FWD testing pattern is summarized in Figure 30. 

Figure 30. Falling-weight deflectometer testing pattern. 

Existing pavement Existing pavement

Precast slab 

Traffic Lane 

Shoulder 

4 

1 2 3 Wheel path ~ 36” 

Test pattern repeated on 

all panels 
 49 

Performance Evaluation at I-25 Test Site 

Figure 31 illustrates the peak (midslab) average deflections measured at location 4 for 81 panels. 

The thickness ranges from 140 to 184 mm (5.5 to 7.25 in.). The peak (average) deflections range 

from 0.14 to 0.30 mm (5.6 to 12.1 mils). On average the thinner panel sections experience higher 

deflections than thicker panels. Figure 32 illustrates the peak (edge) average deflections 

measured at location 2 on the precast panels. The relationship between the deflection magnitude 

and slab thickness is similar to the one observed in Figure 31. Figures 33 and 34 illustrate the 

peak joint deflections. The error bars indicate the scatter in the measured deflection data. This 

scatter can be attributed to the possible variability in support under the panel in the vicinity of the 

joint. Based on the data presented in Figures 31 through 33, the following observations can be 

made: 

 On average, the peak deflections at the joints for thinner slabs are higher than the thicker 

slab joint deflections. 

 Irrespective of slab thickness, joints between the precast panels and the existing slab 

(approach or departure) deflect less than the joint between two new precast panels. 

 The deflection data scatter (as seen in the error plots) is more for joints between two new 

precast panels than for joints between the existing slab and the precast panel. It is 

premature to speculate on the reasons for this differential behavior. 

0

5

10

15

20

5.5" 6.25" 7.25"

Average midslab deflection, mils 

n = 14 n = 45 n = 22

"n" indicates number of tested panels

Figure 31. Average midslab deflections as a function of slab thickness. 
 50 

0

5

10

15

20

5.5" 6.25" 7.25"

Average edge deflection, mils 

n = 14 n = 45 n = 22

"n" indicates number of tested panels

Figure 32. Average edge deflections as a function of slab thickness. 

0

5

10

15

20

5.5" 6.25" 7.25"

Average deflection, mils 

Ex. slab next to new panel

New panel next to ex. slab

New panel next to new panel

"n" indicates number of tested 

panels and existing slabs

n=1 n=1 n=13 n=7 n=7 n=38 n=3 n=3 n=19

Figure 33. Average joint deflections (approach) as a function of slab thickness. 
 51 

0

5

10

15

20

5.5" 6.25" 7.25"

Average deflection, mils 

Ex. slab next to new panel

New panel next to ex. slab

New panel next to new panel

"n" indicates number of tested 

panels and existing slabs

n=1 n=1 n=13 n=7 n=7 n=38 n=3 n=3 n=19

Figure 34. Average joint deflections (leave) as a function of slab thickness. 

Multiple performance evaluation surveys were conducted by CDOT personnel. The panel 

distresses as classified by the CDOT inspectors are as follows: 

• TYPE I: Corner or tab of panel has a full-depth crack, however, the slab is still stable and 

on grade. 

• TYPE II: Corner or tab of panel has a full-depth crack, and is experiencing minimal 

vertical movement under load. 

• TYPE III: Corner or tab of panel has one or more working cracks and is experiencing 

vertical movement under load. 

 

 The distribution of distress as reported by CDOT is as follows: 

1. 85 percent (23 out of 27) of the panels that are 140 mm (5.5 in.) thick have at least one 

tab that has failed or exhibits some level of distress. 

2. 24 percent (23 out of 97) of the panels that are 160 mm (6.25 in.) thick have at least one 

tab that has failed or exhibits some level of distress. 

3. 3 percent (1 out of 30) of the panels that are 185 mm (7.25 in.) thick have at least one tab 

that has failed or exhibits some level of distress. 

The majority of these cracks were in the vicinity of the fiberglass stitches. A typical crack pattern 

is illustrated in Figure 35. 
 52 

 

a) 

b) 

Figure 35. Typical crack patterns. 

The possible reasons for this premature failure include nonuniform support in the vicinity of the 

stitches resulting in tensile stresses at the top fibers of the panel; inadequate slab thickness to 

carry the axle loads; and longer effective slab lengths due to joint ties. 

Fiberglass stitch

Cracking with associated spalling
 53 

RECOMMENDATIONS FOR PRECAST PANEL INSTALLATION 

Based on this experience the following recommendations are suggested for future precast panel 

installations for full-depth repair of jointed concrete pavements: 

1. Reduce the slab length. 

2. Slab thicknesses less than 200 mm (8 in.) should not be used. 

3. The precast panel should be connected to the existing panels through dowels to ensure 

joint flexibility and load transfer. 

4. Whenever possible, multi-tasking during the installation process should be encouraged to 

reduce construction time. Construction and installation time can be positively impacted if 

the repair locations are in close proximity of each other, allowing for the installation of 

multiple panels under one traffic control setup. 

APPENDIX A 

Example of Field Data Sheet 
 56 

Pre-cast Concrete Panel System for Full Depth Pavement Repairs 

Field Data Sheets 

Date: ________________ 

PROJECT LOCATION

 Location*:________________________________________________________ 

 _________________________________________________________ 

 _________________________________________________________ 

 _________________________________________________________ 

*Be sure to include mileposts or exit numbers 

INVENTORY INFORMATION

 Cross-section details: 

 Slab thickness: ________________________ 

 Base thickness and type: ________________________ 

 Subbase thickness and type: ________________________ 

 Subgrade type: ________________________ 

Pavement Type: JPCP or JRCP 

 Joint spacing: ___________________________ 

 Shoulder type and width: ___________________________ 

 Traffic: 

 AADT: ___________________________ 

 %Commercial: ___________________________ 
 57 

DISTRESS INFORMATION*

 Patch ID #: _____________________________________________________ 

 Location: _____________________________________________________ 

*Record the extent and severity of the distress. Photograph ALL representative 

distresses. 

 

Example distress types: Transverse and longitudinal cracking, spalling, faulting, 

ASR, D-Cracking, corner cracks, pop-out, sealant damage, asphalt patches. 

APPENDIX B 

Construction Guidelines Presentation 
 60 

Slide 1 

Precast Concrete Panel System 

for Full Depth Pavement 

Repairs-Construction Guidelines

Federal Highway 

Administration

This presentation is intended to provide 

guidance on the installation of precast 

concrete panels as a full-depth repair 

alternative. 

Slide 2 

Acknowledgements

The project team would like to acknowledge

the financial support of the Federal Highway

Administration and the Michigan Department

of Transportation.

The project was sponsored by the Federal 

Highway Administration under the Concrete 

Pavement Technology Program Task 7. 

Additional financial assistance was provided 

by the Michigan Department of Transportation, 

which also provided the project sites along 

M-25 and I-675. 

Slide 3 

Why use “Fast Track” Repairs?

The traditional practice of rehabilitating 

existing concrete pavements is an excellent 

method to extend the remaining service life of 

the overall network. However, increasing 

traffic volumes and sensitivity to user delays 

and costs have required pavement 

construction and rehabilitation to be put on a 

“fast track” as much as possible. 

Slide 4 Potential Advantages of 

Precast Panels

9Minimize curling of the slab.

9Improved material properties.

9Reduce traffic delays and user 

costs.

9Improve construction uniformity.

Structural precast concrete elements have 

been successfully used in the building and 

bridge industry. Precast concrete elements are 

constructed under controlled curing conditions, 

resulting in improved short- and long-term 

durability properties. Since the panels are 

cured under controlled conditions the 

mechanical properties of the resulting 

concrete are not compromised. Since multiple 

slabs are fabricated at the same time, this 

leads to uniformity of construction. 
 61 

Slide 5 “Typical” Candidate 

Distresses

(a) (b)

(c) (d)

Typical distresses include (a) deteriorated 

joints with asphalt cold patch (b) medium 

severity mid panel cracking with associated 

spalling, (c) high severity transverse cracking, 

and (d) deteriorated joint (sealant damage) 

with associated spalling.

Slide 6 Precast Panel Structural 

Details Lift Hook

Cluster of dowel bars

1.25 or 1.5” in dia.,

spaced @ 12” on center

Existing

Slab Existing

Slab #5 epoxy

Coated bar

6’

Precast Panel 12’

Three 1.25” diameter dowels (10” thick slab) 

or 1.5” diameter dowels (12” thick slab) are 

placed at 12” on center along the wheel path. 

This placement is very similar to dowel bar 

retrofit construction. The mid panel 

temperature steel is optional. The temperature 

steel consists of 3/8” steel bars placed at 6” on 

center held together by 1⁄4” ties. The panels 

are 6 feet long and 12 feet wide.

Slide 7 Construction Sequence using 

HDP foam (typical)

9 Offsite activities

 Casting of the panels (precast or ready mix 

plant).

 Storage of fabricated precast panels.

9 Onsite activities

 Documentation of distresses

 Type, extent and severity levels

 Slab (existing) demolition

 Saw cutting of the repair boundaries

 Saw cutting of dowel slot outlines in the existing panel

 Removal of distressed panel

The construction process includes a variety of 

operations.

Slide 8 Construction Sequence 

(typical)

9Onsite activities, contd.

Initial cleaning of the base layer

 Removal of debris

 Dewatering (if needed)

Cutting (jack hammering) of dowel slots 

to specification depth.

Final cleaning and grading of base layer.

Cleaning (pneumatic) and sand blasting 

of dowel slots.
 62 

Slide 9 Construction Sequence 

(typical)

9 Onsite activities, contd.

 Check base grade and elevation.

 Transport precast panel to the repair site and 

check initial panel alignment and elevation.

 Conduct final adjustments.

 Final placement of panel 

 Drill holes for the injection of HDP foam.

 Inject HDP foam to stabilize and level the panel.

 Grout dowel slots and lift hook holes.

 Seal joints and open to traffic.

Slide 10 Fabrication of Precast PanelsOffsite Activity

Placement of panel steel 

and dowel bars

Completed mold for 

precast panels

The precast panels can be fabricated at either 

a precast plant or a ready-mix concrete yard. 

A series of slab forms are fabricated with the 

appropriate joint and panel reinforcement. 

Slide 11 Fabrication of Precast PanelsOffsite Activity

Placement of fresh concrete Completed precast panel

It is recommended that fresh concrete 

property tests be performed. The mechanical 

property tests should include flexural and 

compressive strength tests.

Slide 12 Fabrication of Precast PanelsOffsite Activity

Surface texturing Concrete curing

It is recommended that the completed panels 

be textured and cured. 
 63 

Slide 13 

Typical PCC Mixture Design

Cement (type I): 500-650 lbs*

Water: 200-250 lbs

Coarse Agg: 1500-2000 lbs

Fine Agg: 1200-1400 lbs

Admixtures: AEA, WRA (if needed)

Target 28-day f’c: 4000-6000 psi

Target slump: 1-3”

*All weights are for 1 yd3 of concrete.

Standard concrete paving mixture designs are 

suitable for precast concrete fabrication.

Slide 14 Installation of Precast PanelsOn site activities

Saw-cutting of panel boundaries and dowel slots

The slab removal boundaries are outlined and 

saw cut. The limits of the pavement area to be 

removed are sawed in the transverse 

direction. 

Slide 15 Installation of Precast PanelsOn site activities

Removal of distressed panel

Following the saw cutting operation, the lift 

hooks are inserted and the distressed slabs 

are removed using a front-end loader. During 

this process, the outline for the dowel slots in 

the adjacent panels is also cut. 

Slide 16 Installation of Precast PanelsOn site activities

Initial cleaning and grading of base course

It is recommended that the base be excavated 

1.5-2” below the bottom of the existing slab to 

accommodate the precast panel. The base 

should be cleaned and dewatered (if 

necessary).
 64 

Slide 17 Installation of Precast PanelsOn site activities

Jack hammering of dowel slots

The dowel slot cutting and preparation 

includes (i) initial grooving to the required 

depth with a concrete saw; (ii) jack hammering 

of the concrete to carve out the dowel slot.

Slide 18 Installation of Precast PanelsOn site activities

Sandblasting of dowel slots

The dowel slot preparation also includes (i) air 

cleaning of dowel slot to remove debris and 

any loose concrete pieces; and (ii) sand 

blasting of the dowel slots. The dowel slots are 

approximately 4” wide and 5.25” deep (base of 

the slot cut). 

Slide 19 Installation of Precast PanelsOn site activities

Schematic cross-section of the dowel assembly

Graded aggregate base Flowable fill or HDP

Dowel slot Dowel bar

Panel

Thickness

Existing

Pavement

Precast

Panel

18”

Slide 20 Installation of Precast PanelsOn site activities

Placement of precast panel

The precast panels are transported from the 

flat-bed truck to the excavation using a frontend loader. 
 65 

Slide 21 Installation of Precast PanelsOn site activities

Elevation adjustment of precast panel using HDP foam

A series (approximately 4–6 holes/panel) of 

holes (5/8” in diameter) are drilled to inject the 

foam. The polyurethane foam is made from 

two liquid chemicals that combine under heat 

to form a strong, lightweight, foam-like 

substance. The chemical reaction between the 

two materials causes the foam to expand and 

fill the voids. According to the manufacturer’s 

specification, the HDP foam sets in 

approximately 15 minutes (approximately 90% 

of full compressive strength), and the precast 

panel is ready to carry load. For the purpose 

of slab stabilization, the foam density is about 

4 lbs/ft3

 with a compressive strength range of 

60 psi to 145 psi.

Slide 22 Installation of Precast PanelsOn site activities

The characteristics of the HDP foam are:

 Setting time is approximately 15 minutes 

to achieve 90% of full compressive 

strength.

 The foam density is about 4 lbs/ft3

 The compressive strength ranges from 

60-145 psi.

 The injection port hole diameter is 5/8”

Slide 23 Installation of Precast PanelsOn site activities

Backfilling of dowel slots

Once the slab elevations are verified and 

deemed acceptable, the dowel slots are 

grouted and the joints are sealed. 

Slide 24 Installation of Precast PanelsOn site activities

Completed precast panel
 66 

Slide 25 Construction Activity –

Typical Timeline

A4 Final cleaning and grading of the exposed base layer

Cutting (jack hammering) of dowel slots

•Saw cutting of repair boundaries

•Saw cutting of dowel outlines

•Removal of distressed panel

A3

Initial cleaning of the exposed base layer

•Removal debris

•Dewatering (if needed)

A2

Slab demolition

• Saw cutting of repair boundaries

• Saw cutting of dowel outlines

• Removal of distressed panel

A1

Activity Description

Slide 26 Construction Activity –

Typical Timeline, contd

A8 Grout dowel slots, seal joints and open to traffic

Drill port holes and inject foam to support and align the 

panels. A7

A6 Transport, placement and alignment of precast panels

A5 Air cleaning and sand blasting of dowel slots

Activity Description

Slide 27 Typical Timeline (I-675)-

Example

Example Gantt Chart illustrating time taken to 

complete installation of one panel.

Slide 28 Typical Timeline (M-25)-

Example

Example Gantt Chart illustrating time to 

complete the installation of two panels 

(multitasking and overlapping of activities).
 67 

Slide 29 Construction Activity –

Typical Timeline

A8 26 Grout mixer (2)

Drills and HDP injection equipment 

(2) A7 25

Front end loader (1 operator), 3 

additional to guide the alignment A6 20

A5 21 Sand blasting equipment (2)

A4 15 Plate compactor (1)

A3 20 Two Pnuematic jackhammers (2)

A2 5 Nothing specific (2)

Concrete saw (1), front end loader (1 

operator) A1 60

Recommended Equipment 

(labor needs)

Time, 

minutes

Activity 

Code

Slide 30 

Repair Effectiveness

9Measure joint widths along transverse 

and longitudinal joints.

9Determine panel deflections using the 

falling deflectometer (FWD)

Slide 31 Repair EffectivenessStructuralPhotograph of a falling weight deflectometer 

(FWD).

Slide 32 Recommended FWD Test 

Pattern

Existing 

Slab

Existing 

Slab

Approach Joint

Leave Joint

Mid Slab

1 2 3 4

5 6 7 8

9

1 = Approach OWP (BJT); 2 = Approach OWP (AJT)

3 = Leave OWP (BJT); 4 = Leave OWP (AJT)

5 = Approach IWP (BJT); 6 = Approach IWP (AJT)

7 = Leave IWP (BJT); 8 = Leave IWP (AJT)

9 = Edge 

Load positions of the FWD to determine 

structural effectiveness.
 68 

Slide 33 Repair EffectivenessStructural

9Data from locations 1, 2, 3, 4, 5, 6, 7 

and 8 can be used to determine 

approach and leave load transfer 

efficiencies (LTEs) along the wheel 

paths.

(%) •100

Δ

Δ =

L

u LTE

Unloaded side deflection

Loaded side deflection

Slide 34 Repair EffectivenessStructural

9Peak deflections from locations 1, 2, 3, 

4, 5, 6, 7 and 8 can be compared with 

the peak deflection at location 9. This 

comparison gives information about 

the uniformity (or lack of it) of 

support.
APPENDIX C 

Sample Specification for Precast Full-Depth Concrete Pavement Repair 
70 

MICHIGAN 

DEPARTMENT OF TRANSPORTATION 

SPECIAL PROVISION 

FOR 

PRECAST FULL DEPTH 

CONCRETE PAVEMENT REPAIR 

C&T:VTB 1 of 4 C&T:APPR:TH:JFS:12-19-02 

 a. Description. The work consists of fabricating and installing precast full-depth concrete pavement 

repairs at locations shown on the plans, or as directed by the Engineer. All work shall be according to the 

Standard Specifications for Construction and this special provision. 

b. Materials. The concrete used in the fabrication of the precast panels shall be MDOT Grade P1 

according to the Standard Specifications for Construction. The Engineer will provide the concrete mix 

proportions based on the contractor’s materials selection. 

 The fabrication of the precast panels shall be done according to the special details included in this 

special provision. 

 Prior to stripping the forms, the precast panels shall have a minimum flexural strength of 500 psi. The 

precast panels shall have a 7 day continuous wet cure commencing immediately after final finishing with 

all exposed surfaces covered. The precast panels shall have a minimum cure of 14 days prior to 

placement. 

 The Contractor shall supply test data (slump, air voids, unit weight) for the fresh concrete, and flexural 

and compressive strengths for the hardened concrete after 7, 14, and 28 days (if applicable). 

 Concrete patching materials used to backfill the slots shall be selected from the Qualified Products 

List for Prepackaged Hydraulic Fast-Set Patching included in the Materials Source Guide. The patching 

material shall be extended with aggregate, up to the maximum amount specified in the Qualified Products 

List. If a curing compound is recommended by the manufacturer of the patching material, it shall be in 

accordance with subsection 903.05 of the Standard Specifications for Construction. 

 The leveling material shall be a flowable fill. The Engineer will provide the mix design. 

 The aggregate used in the patching materials shall be a dry, clean, crushed 26A gradation 

conforming to subsection 902.03 of the Standard Specifications for Construction, or equivalent as 

approved by the Engineer. 

c. Construction. All the saw cutting on the existing concrete pavement shall be done in accordance 

with paragraph six of Section 603.03.B.1.b of the Standard Specifications for Construction. The 

Contractor is responsible for insuring that the precast patch and dowels will properly align with the 

removal area and the dowel bar slots. 

 The slots for the dowel bars shall be cut using a diamond-bladed saw machine. The machine shall be 

capable of cutting a minimum of three slots simultaneously that are centered over the edge of the repair. 

Three slots will be made in each wheel path. The bottom of the slots shall be have a minimum flat 

distance of 10 inches into the existing concrete pavement. 

 Any loose concrete shall be vacuumed or removed from the slots and all surfaces shall be dry, 

abrasive blast cleaned. Any exposed steel shall be blast cleaned to remove any rust or laitance. 

Immediately prior to placement of the patching material, the slots shall be final cleaned with moisture-free, 

oil-free compressed air having a minimum pressure of 90 psi. 

 The slot walls and bottom must be dry before placement of the patching material, unless otherwise 

recommended by the manufacturer. 
71 

 The patching material shall be mixed with a portable or mobile mixer. The patching material shall be 

extended, by weight of the cement, with 26A aggregate up to a maximum extension rate as specified in 

the Qualified Products List, and placed according to the manufacturer's recommendations. The patching 

material shall then be consolidated using a hand-held vibrator if recommended by the manufacturer. The 

surface of each dowel-bar patch shall be finished flush with the surrounding concrete and cured 

according to manufacturer's recommendations, even if diamond-grinding of the concrete surface is to 

occur afterward. 

 The Engineer reserves the right to sample the patching material and conduct compressive strength 

testing to verify that the mixture is meeting the requirements stated below. 

 Age of sample Minimum Compressive Strength (psi)

 2 hrs. 2000 

 4 hrs. 2500 

 28 days 4500 

 The area where the precast patch is to be placed shall be excavated to a minimum of 12 inches 

below the top of the existing concrete pavement and shall be free of all debris and standing water. 

 The existing granular base material shall be moistened just prior to the placement of the flowable fill 

to prevent absorption of mix water into the underlying granular base material. 

 Flowable fill shall be placed in the excavated pavement area and leveled to the appropriate depth 

below the top of the existing pavement to allow the precast panel to be placed level with the top of the 

existing concrete pavement. 

 The width of the transverse joints between the precast panel and the existing pavement shall be 

equal on both sides of the precast panel with a width of 3/4 inch ± 1/4 inch. 

 The smoothness of the roadway after placement of the precast pavement patches shall meet the 

straightedge requirements in paragraph three of subsection 603.03.B.8 of the Standard Specifications for 

Construction. 

 Joint sealing shall be done in according to requirements specified for resealing transverse and 

longitudinal pavement joints described in Section 603.03 of the Standard Specifications for Construction. 

 Patching of the lift holes shall be done using the same material used to back fill the dowel bars. 

d. Opening to Traffic. Vehicular traffic shall not be permitted on the panel area until the prepackaged 

hydraulic fast set material used to fill the dowel bar retrofit slots has attained the proper curing time and 

compressive strength as specified by the product manufacturer. 

 e. Measurement and Payment.

 Contract Item (Pay Item) Pay Unit

 Precast Pavement Patch, 10 inch.................................................................................Each 

 Measurement for Precast Pavement Patch,10 inch is based on each in-place precast patch. 

 Payment for Precast Pavement Patch,10 inch includes all labor, equipment, and materials required 

to remove, and dispose of the existing concrete in the patch area, cut and clean the dowel bar slots, 

repair spalls, place the flowable fill, cast the precast patch, transport and install the precast patch, backfill 

the dowel bar slots and lift holes with a concrete patching material, sealing the joints, and cure the backfill 

material. 
72 
73 

REFERENCES 

ASTM International. Oct 1, 2004. ASTM D 1621 REV A: Standard Test Method for Compressive 

Properties of Rigid Cellular Plastics. ASTM International, West Conshohocken, PA. 

Bull, J. W. 1988. “The Use of Precast Concrete Raft Units for Roads.” Highways, vol. 56, no. 

1936, London, England, U.K., April, pp. 35–36. 

Correa, A. L., and B. Wong. 2003. Concrete pavement rehabilitation guide for full-depth 

repairs. Federal Highway Administration, FHWA-RC Atlanta 1/10-03 (5M), August. 

Davids, Bill. 2003. EverFE Theory Manual. University of Maine, Orono. 

FHWA. 1994. Accelerated Rigid Paving Techniques, State-of-the-Art Report, Special Project 

201. (FHWA-SA-94-080). Federal Highway Administration, Washington, DC. 

FHWA. 2003. LTPP Distress Identification Manual for the Long-Term Pavement Performance 

Program (FHWA-RD-03-031). Federal Highway Administration, Washington, DC. 

Grimsley, R. F., and B. G. Morris. 1975. An Approach to Concrete Pavement Replacement That 

Minimizes Disruption of Traffic. Special Report 153. Transportation Research Board, National 

Research Council, Washington, DC, pp. 107–110. 

Hachiya, Y., F. Akamine, O. Takahashi, and Y. Miyaji. 2001. “Rapid Repair With Precast 

Prestressed Concrete Slab Pavements Using Compression Joint System.” Proceedings of 7th 

International Conference on Concrete Pavements. International Society for Concrete Pavements, 

Orlando, FL, September, pp. 891–905. 

Lane, R., and T. Kazmierowski. 2005. “Use of Innovative Pre-Cast Concrete Slab Repair 

Technology in Canada.” Proceedings, 8th International Conference on Concrete Pavements,

Colorado Springs, Colorado, August 2005, pp. 771–789. 

Merritt, D. K., B. F. McCullough, and N. H. Burns. 2003. “Precast Prestressed Concrete 

Pavement Pilot Project Near Georgetown, Texas.” Transportation Research Record 1823.

Transportation Research Board, National Research Council, Washington, DC, pp. 11–17. 

Meyer, A. H., and B. F. McCullough. 1983. “Precast Repair of CRC Pavement.” Journal of 

Transportation Engineering, vol. 109, no. 5, American Society of Civil Engineers, New York, 

NY, pp. 615–630. 

Overacker, J. W. 1974. “Thruway Repairs Concrete Slabs Overnight.” Public Works, vol. 105, 

no. 3, New York, NY, March 1974, pp. 63. 

Sharma, A. K. 1990. “Experimental Rehabilitation of Jointed Portland Cement Concrete 

Pavement.” Transportation Research Record 1272. Transportation Research Board, National 

Research Council, Washington, DC, pp. 27–34. 
74 

Simonsen, J. E. 1971. Concrete Pavement Joint Repair With Pre-cast Slabs, Progress Report. 

Research project 68 F-102, Research report R-762. Michigan State Highway Commission, 

Lansing. April 1971. 

Simonsen, J. E. 1972. Concrete Pavement Joint Repair With Pre-cast Slabs, Construction 

Report. Research project 68 F-102, Research report R-804, Michigan State Highway 

Commission, Lansing. February 1972. 

Speir, R. H., S. D. Tayabji, G. R. Rada, Y. S. Chen, and S. Murrell. 2001. “Feasibility Study for 

the Use of Precast Portland Cement Concrete Panels for Rehabilitation of Airfield Pavements.” 

Proceedings of 7th International Conference on Concrete Pavements, International Society for 

Concrete Pavements, Orlando, FL, pp. 907–922. 

Tyson, S. S. 1976. Full-depth Repair of Jointed PCC Pavements Cast-in-place and Precast 

Procedures. Virginia Highway and Transportation Research Council, VHTRC 76-R44, 

Charlottesville. 
 
a

Office of Infrastructure

bcd

Office of Pavement Technology

Federal Highway Administration

U.S. Department of Transportation

400 Seventh Street SW, HIPT-20

Washington, DC 20590

Telephone: 202-366-0120

Fax: 202-493-2070

www.fhwa.dot.gov/infrastructure/pavement/concrete

FHWA-HIF-07-019