TRANSPORTA TJON RESEARCH RECORD 1307 221

Case Studies in Rehabilitation Strategy Development

MICHAEL I. DARTER AND KATHLEEN T. HALL

The performance and rehabilitation of jointed concrete pave­ments was recently investigated in a major national field study. Among the products of the research were detailed guidelines prepared to i;ssist practicing engineers in determining when res­toration was likely to be cost-effective, and when a structural overlay was required. The data base for this project included 95 ections of joint reinforced con.crete pavement and joint plain

concrete pavement in their first performance period. Thirteen of these sections were selected for use as case studies in rehabili­tation strategy development. The sections were selected to cover the range of four major climatic zone of the United tates, a well as a range of pavement condition from good co poor (as­ses ed on the basis of cracking, joint deterioration, joinr faulting, pumping, and serviceability). The EXPEAR computer program was used to evaluate the current condition of each pavement section, predict its future condition without rehabilitation, and compare the predicted performance and co !-effectiveness of var­ious rehabiJitation strategies. The case studies demonstrated that restoration is the most cost-effective alternative for pavements that are structurally adequate and do not have concrete durability problems.

Restoration is a rehabilitation strategy that involves a com­bination of methods for repairing distress, improving ride quality, and extending pavement life without a structural ov­erlay. Restoration techniques for jointed concrete pavements include the following:

1. Full-depth repair of joints, cracks, and corner breaks; 2. Partial-depth repair of spalls; 3. Grinding to remove faults and studded tire ruts and to

improve surface friction; 4. Grooving to improve surface friction; 5. Subsealing to fill voids under slab corners; 6. Slabjacking to improve the pavement's longitudinal

profile; 7. Load transfer restoration at joints and cracks; 8. Joint resealing; 9. Crack sealing;

10. Subdrainage improvement; and 11. Shoulder improvement.

Concrete pavement restoration typically involves a com­bination of several of these techniques. Over the past 25 years, many states have gained experience with restoration, and de­tailed information on design, construction, and performance of various restoration techniques is available from a variety of sources. (1-4)

M. I. Darter, ERES Consultants, Inc., 8 Dunlap Court, Savoy, Ill. 61874. K. T. Hall, University of Illinois at Urbana-Champaign, 1206 Newmark Lab, 205 N. Mathews, Urbana, Ill. 61801.

Little guidance is available, however, to assist the practicing engineer in determining whether a particular pavement is a good candidate for restoration, or whether another rehabil­itation strategy would be more appropriate. Restoration has been applied to many pavements which were really in need of structural improvement. The result, even if the restoration is well designed and well constructed, is short rehabilitation life, high life cycle costs, and diminished confidence in the effectiveness of restoration among engineers and highway users. It is possible for practicing engineers to assess the appropri­ateness of restoration, using information available about the design and condition of a particular pavement section, re­habilitation performance prediction models, and rehabilita­tion cost data. The EXPEAR computer program can be used for the purpose of comparing rehabilitation strategies for 13 pavement projects across the United States and representing a wide range of pavement conditions.

PAVEMENT PERFORMANCE AND REHABILITATION NEEDS

Maintenance Versus Restoration

The success of restoration depends on good design and con­struction, but it also depends on application of restoration at the appropriate time in the performance life of a pavement. The earliest time that restoration should be done is relatively easy to identify. Early in a pavement's life, its condition is excellent and its rate of deterioration is slow. For several years, routine or preventative maintenance is more cost­effective than any rehabilitation strategy. Restoration is gen­erally not warranted until distresses such as cracking, faulting, and joint spalling have developed to the point that they detract from the pavement's serviceability. When annual mainte­nance costs equal or exceed the equivalent annual cost of restoration, the restoration work is justified.

Restoration Versus Resurfacing

It is more difficult to identify the latest point in the pavement's life at which restoration is likely to be cost-effective, i.e., the point at which the pavement has carried so much traffic and sustained so much structural damage that an overlay is needed. It is conceivable that resurfacing may be done before this point and be more cost-effective than restoration, primarily because of the ability of overlays to reduce deflections and slow deterioration in the slab. Early resurfacing seldom oc-

222

curs, however, because of funding limitations . More fre­quently, restoration is performed some years after the time when it has the greatest potential to cost-effectively extend the pavement's life, and in some cases, after the time when a structural improvement is wammteri. The longer the delay, the less likely it is that restoration will be able to compete with resurfacing in performance and cost-effectiveness.

Indicators of Structural Deficiency

The following is a list of key distresses and levels that should be considered in assessing structural damage in jointed con­crete pavement. The critical values suggested are based on observations of joint plain concrete pavement (JPCP) and joint reinforced concrete pavement (JRCP) performance in previous studies ( 4-6) as well as from the data base, and from use of EXPEAR (7) to predict the performance of restoration on pavements with varying levels of deterioration.

1. Transverse cracking provides direct evidence of fatigue damage. In JRCP, low-severity cracks are considered a nor­mal consequence of drying shrinkage after construction, and are not considered structural distresses. In JPCP, unless the joint spacing is too long, transverse cracking of any severity is evidence of structural damage. Suggested critical levels for transverse cracking are 10 percent slabs cracked or 70 cracks per mile (all severities) for JPCP, and 70 cracks per mile (medium or high severity) for JRCP.

2. Longitudinal cracking in highway pavements is almost always caused initially by factors other than traffic (e.g., poor joint construction or foundation movement), but under traffic it can deteriorate to such an extent that it constitutes structural damage. More than 500 ft of longitudinal cracking per mile is suggested as a critical level for both JPCP and JRCP.

3. Joint faulting and pumping are not generally considered structural distresses, but they are caused by traffic loads and are visible indications of progressive loss of joint load transfer and erosion of slab support. Suggested critical levels of joint faulting are 0.10 in. for JPCP and 0.25 in. for JRCP.

4. Corner breaks, which occur as a result of substantial erosion of slab support and high corner deflections, are def­inite indications of structural damage. The suggested critical level for corner breaks is 25 per mile for both JPCP and JRCP.

5. Transverse joint spalling that reduces the thickness of the slab at the joints should be considered structural damage because it diminishes the structural integrity of the slab and is progressive in nature. It is often caused by poor joint con­struction, dowel bar corrosion, D cracking, or reactive ag­gregates. Suggested critical levels for joint spalling are 50 spalled joints per mile (medium or high severity) for JPCP and 25 spalled joints per mile (medium or high severity) for JRCP.

If JRCP or JPCP exhibits levels of structural damage be­yond those listed, the pavement has probably reached or passed the point at which the rate of deterioration begins to accel­erate rapidly. At this stage, a structural improvement is most appropriate. Restoration work performed on a pavement that has deteriorated past this point is likely to µrovidt: a relatively short performance life under medium to heavy traffic con-

TRANSPORTATION RESEARCH RECORD 1307

ditions. Attempting to delay a structural improvement by con­tinued patching may result in annual maintenance costs so high that they completely offset any savings achieved by the delay.

Although visible distress is a good indicator of structural damage, it cannot give a complete picture of the extent of underlying deterioration. Coring and deflection testing are strongly recommended on any project being seriously consid­ered for rehabilitation.

PAVEMENT EVALUATION AND REHABILITATION USING EXPEAR

EXPEAR is a computerized system to assist highway engi­neers in project-level evaluation of concrete highway pave­ments, development of feasible rehabilitation strategies, and prediction of rehabilitation performance and cost­effectiveness. EXPEAR is intended for use in rehabilitation planning and design for high-volume (e.g., Interstate) con­ventional concrete pavements [JRCP, JPCP, and continuously reinforced concrete pavement (CRCP)]. EXPEAR was orig­inally developed for the FHWA (7) and has been further developed with the support of the Illinois Department of Transportation (IDOT). Additional work on EXPEAR has been supported by the FHWA under this research study (8). Additional information on the development of EXPEAR is available (9-11). The current version is EXPEAR 1.4, which possesses the capabilities to do life cycle cost analysis and delay rehabilitation up to 5 years .

EXPEAR has been developed in the form of a knowledge­based expert system, which simulates a consultation between an engineer and an expert in concrete pavements. EXPEAR uses information about the pavement to guide the engineer through evaluation of a pavement's present condition and development of one or more feasible rehabilitation strategies. The procedure was developed through extensive interviewing of authorities on concrete pavement performance. In addi­tion, predictive models are used to estimate future pavement performance with and without rehabilitation.

CASE STUDIES

Sections Evaluated

The data base developed under this contract includes 95 sec­tions of JPCP and JRCP in their first performance period (6). Thirteen of these sections were selected for evaluation with the EXPEAR program. The sections, both JRCP and JPCP and located in all four major climatic zones, are presented in Table 1. The condition of each section was subjectively as­sessed as good, fair, or poor on the basis of observed distress and serviceability. Pavements rated as good had little or no cracking or joint deterioration, minimal joint faulting, no pumping, and a present serviceability rating (PSR) of 3.5 or more. Fair pavements had at least one of the following: mod­erate cracking or joint deterioration because of D cracking or reactive aggregate distress), moderate to high faulting (ex­ceeding the critical level), visible pumping, or PSR less then 3.5. Pavements rated as poor had at least two and in most

Darter and Hall 223

TABLE I CASE STUDIES SELECTED FROM THE FHWA-ERES DATA BASE

Section Cllatat~ Joint Joint

Type Condition CrKkl"I ~tutori1Uon Fau!U"I Pwnpl"' PSR (no/mile) (no / mile) (Inch) (0-5)

AZ 1-6 DNF )PCP Good .0 5 0.01 None 3.5 FL 2 WNF ]PCP Good 0 0 0.01 None 3.7 MI 3 WF JRCP Good 0 0 0.02 None 4.8 MN3 DF JRCP Good 0 0 0.00 None 3.8 MN 2-3 DF JRCP Good 0 5 0.05 None 4.0

CA 6 DNF ]PCP Fair 0 2 0.15 None 3.4 NC 1-8 WNF ]PCP Fair 20 5 0.22 None 3.3 NC2 WNF ]PCP Fair 0 0 0.02 High 4.2 NJ 2 WF JRCP Fair 24 14 0.06 None 3.8

CA 1-3 DNF ]PCP Poor 30 10 0.10 Medium 3.0 MI 4-1 WF JRCP Poor 222 0 0.12 None 2.4 MI 1-lOb WF }PCP Poor 0 219 0.19 Low 2.8 MNl-8 DF JRCP Poor 102 141 0.09 None 3.4

Notes: Condition rating (good, fair, or poor) is subjective assessment of overall pavement

condition, based on visible distress and PSR in outer traffic lane.

Sections CA 6 and CA 1-3 have low-severity reactive aggregate distress.

cases three or four of the following: substantial cracking or joint deterioration (exceeding critical levels) , high faulting (exceeding the critical level), visible pumping, and PSR less than 3.0.

Evaluation Procedure

All EXPEAR input data required for each section were ob­tained from the data base. The following steps were carried out for each of the 13 projects.

1. Input data were verified by state employees and project team members familiar with the sections.

2. A pavement evaluation was concluded and future perfor­mance was predicted without any rehabilitation.

3. The following rehabilitation alternatives were consid­ered:

• Restoration ; •Resurfacing options [conventional asphalt concrete (AC)

overlay, crack and seat AC overlay, saw and seal AC overlay, bonded PCC overlay, and unbonded PCC overlay]; and

•Reconstruction with JPCP or JRCP.

4. Rehabilitation performance was predicted using models contained in EXPEAR for distress after restoration (faulting, cracking, joint spalling, and PSR), resurfacing (rutting and reflective cracking for AC overlays; faulting , cracking, and joint spalling for PCC overlays) and reconstruction (faulting, cracking, joint spalling, and PSR).

5. Life cycle costs were estimated using Illinois statewide average costs. The costs include traffic control and other mis­cellaneous costs normally associated with the alternatives (guardrails, signs , etc.).

Because of the highly variable nature of pavement reha­bilitation costs throughout the United States, the cost analyses

should be considered only as examples for comparison of the relative cost-effectiveness of various strategies.

All of the projects were surveyed in 1987 and analyzed using EXPEAR in 1989. This 2-year delay is taken into account in the analyses: EXPEAR calibrates the performance prediction models to the 1987 distress and levels, predicts the distress levels in 1989, and uses these levels to compute rehabilitation quantities and costs . For some projects in very good condition, the rehabilitation was delayed an additional few years in the analysis .

AZ 1-6, Good Condition

Table 2 presents the results of the analysis of AZ 1-6, a section of 9-in. JPCP located on Route 360 near Phoenix, Arizona, in a dry, nonfreezing climatic zone. The pavement has carried about 2 million 18-kip equivalent single-axle loads (ESALs) in the outer traffic lane since its construction in 1981. When surveyed in 1987, its PSR value was 3.5, and the only notable distress was some joint spalling. Joint resealing had been attempted, without much success, a year earlier.

Given the low truck level on this pavement section, joint spalling on this pavement section is not predicted to increase significantly over the 20-year analysis period considered, and no other distresses are predicted to reach critical levels. As Table 2 indicates, the strategy with the lowest annual cost is restoration. Restoration could probably also safely be delayed for several years.

FL 2, Good Condition

Table 3 presents the results of the analysis of FL 2, a section of 13-in. JPCP located on 1-75 near Tampa, Florida, in a wet, nonfreezing climatic zone. The pavement has carried about 2 million ESALs in the outer traffic lane since its construction

224 TRANSPORTATION RESEARCH RECORD 1307

TABLE 2 RESULTS OF EXPEAR ANALYSIS OF AZ 1-6

PAVEMENT DESIGN HJghway: Route l6CJ near Phoenix Pavement type: 9-lnch JPCl' Year CONtructed: 1981 )olntspadng: lS-13-lS-17 feet Llowels: Und.oweled Base: 4-lnch Jean concrete Subgrade: A-0 Shoulders: Tied PCC outer, AC Inner Drain&: No dnin11

TRAFFIC Current 2-way ADT: Percent trucks: Lanes each direction: Accumulated ESAL:

97,770 3.8 3 2.01 milUon (outu lane)

EXISTING PA VllMENT CONDmON Year surveyed: 1987 PSR: 3.5 Deteriorated cracks: 0/mlle Deteriorated jolnte: 5/mlle (outer lane)

Joint faulting: Longitudinal cracks: Pumping: PCC surface: Joint sealant damage:

•D" cracking: Reactive aggregate: Settlemenls/heaves:

20/mlle (middle lane) 0.01 ln<h o feet/mile None Tined, not polished Medium severity (,..ealed 1966) None None None

Shoulder condition: Excellent Lane/shoulder }olnt: Fair

PHYSICAL TBS11NG Rl!COMMl!NDATIONS No phyJk<l t .. tlng W<ttant\'d.

PUl'URI! CONDmON WTlllOUT Rl!HAlllLTT A TION Some Joint dolrriontlon lo praen~ but no tlgn!Qcant l~rt'Uf' ol 1ny typo of diiltrlotaHon Is pft'dkbd over the not ;o.yt•r p1riod .

in 1986. When surveyed in 1987, its PSR was 3.7, it had no cracking or joint spalling, and faulting at transverse joints averaged only 0.01 in. The only distress noted was low­severity joint sealant damage.

As Table 3 indicates, the only rehabilitation work needed is joint resealing, which could be done now or delayed a few years with no adverse affects. No other rehabilitation is pre­dicted to be required for this pavement for the next 20 years. It is obvious that none of the available overlay strategies could compete in cost-effectiveness with restoration over the 20-year analysis period.

MI 3, Good Condition

Table 4 presents the results of the analysis of MI 3, a section of 10-in. JRCP located on 1-94 near Marshall, Michigan, in a wet, freezing climatic zone. The pavement has carried about 2.8 million ESALs in the outer traffic lane since its construc­tion in 1986. When surveyed in 1987, its PSR was 4.8, it had no crack or joint deterioration, and minimal faulting. No significant distresses were noted. EXPEAR predicted that the condition of the pavement would be acceptable for at least another 9 years. No restoration or other rehabilitation is war­ranted now. However, the pavement was underdesigned for the traffic levels anticipated on 1-94, and full-depth repair of deteriorated joints and cracks will probably be needed in the future.

CONSEQUl!NCE OF Dl!LAYING Rl!HABILITATION R...,bllltttlon may <tidy be d<Llyed. Soo>e Joint mealing and joint tp;tll Rpalr ii recom01cnd('(I .

PREDICTIID LlFI! OF Rl!HABILITATION

Alternative Restoration 3-lnch ACOL 5-lnch crack/seat AC OL 3-inch .taw /seal AC OL 3-lnch bonded PCC OL 8-lnch unbonded PCC OL 9•h\t:h tt<ON:INcdon

Yan Unacceptable 20+ 7 Rel. eta.eking 6 Rutting 8 Rutting

20+ 20+ 20+

RESULTS OF UFl!-CYCLI! COST ANALYSIS

Initial Annual Altematlve Coot Cost Restoration 59,200 3,800 3-lnch AC OL 274,600 41,500 &-Inch aack/11eat AC OL 273,200 47,500 3-lnch saw/a,.I AC OL 284,300 38,200 3-lnch bonded PCC OL 368,800 2.3,400 II-Inch unbonded PCC OL 514,200 34600 9-lnch recomtru.ctlon 506,000 34000

Cost per 2-lane mile, bued on predlc:ted Uvet shown abow ('20 yt1r1 for bondtd overlay, unbond~ ov~rlay, and rtOOmtr.uctlon) uad dbcou.nt. nfe or 3 percent.

RECOMMl!NDl!D Rl!HABILITATION (1989)

Minot ft81onHon wort. (•pall ,.pair and joint .... aung) could be d.onc llo lmpmvo r1c1 .. bJUty and prevent water and lncOD\preulble lnflllntlon.

RthablllttUon T«hnlquH Full..S1pth ,.pair ol Jolnll Reeeal tnmvene jolntl Reoe1J lane/1houlder jolnll

Quantity 200 'Y 9~ft

IDS60 ft

Quantity per 2-lane mile and shoulden.

MN 3, Good Condition

Table 5 presents the results of the analysis of MN 3, a section of 9-in. JRCP located on 1-90 near Austin, Minnesota, in a dry, freezing climatic zone. The pavement has carried about 1.5 million ESALs in the outer traffic lane since its construc­tion in 1984. When surveyed in 1987, its PSR was 3.8, it had no cracking or joint deterioration, and minimal faulting . The only problem identified in EXPEAR's evaluation of the pave­ment was a possible subdrainage deficiency. As Table 5 in­dicates, subdrainage improvements could be done at low cost to ensure good long-term performance. There is no predicted need for other restoration work or other rehabilitation over the 20-year analysis period.

MN 2-3, Good Condition

Table 6 presents the results of the analysis of MN 2-3, a section of 9-in . JRCP located on 1-90 near Albert Lea, Min­nesota, in a dry, freezing climatic zone . The pavement has carried about 2.8 million ESALs in the outer traffic lane since its construction in 1976. When surveyed in 1987, its PSR was 4.0 , it had no cracking, some joint spalling (5 per mile), and some joint faulting (0 .05 in.). The transverse joints and lane­shoulder joints are poorly sealed.

As Table 6 indicates , restoration could be performed now at low cost , or could safely be delayed a few years. The costs

TABLE 3 RESULTS OF EXPEAR ANALYSIS OF FL 2

PA VBMl!NT DESIGN Highway: 1·'15 near Tampa Pavement type: 13-ln<h JPCP, 14-loot lonet Year constructed: 1986 Joint •pacing: 13-12-111-19 feel Oowela: Doweled, 1.25-lnch diameter Base: 6-lnch untreated aggregate Subgrade: A-3 Shoulde": Tied PCC On.IN:

TRAFFIC Cum!nt 2-way ADI: Percent trucb: L.aocs e1ch dhtttlcn! Accumulated ESAL:

No dralN preeent

28,700 20.0 2 2.00 million (outer lane)

EXISTING PAVEMENT CONDmON Year surveyed: 1987 PSR: 3.7 Deteriorated. cocks: O/m.lle Deteriorated jolnls: O/mlle Joint f1ultlng: o.oi Inch Longltudtn.I cracl01: 0 feet/mile Pumping: None PCC surface: Tined, not polished Joint sealant damage: Low severity •ow cracking: None Reactive aggregate: None Settlements/heaves: None

Shoulder condition: Excellent Lane/shoulder joint: Good

Over.111: The only deficiency b an Inadequate joint sealant reservoir widlh for the existing sealant type.

PHYSICAL TESTING RECOMMENDATIONS No physical tesllng warranted.

FlmlllB CONDmON wrm:our RllHABn.rTATION Servk.,.bWty: Faulting: Jolnt deterioration: Cncldng:

> 3.5 for 20 years c 0.10 lnc:h lor 20 yean 0/mlle for 20 yean I/mile In 20 yean

CONSBQUBNCB OP DBLAYING lll!HABn.rTATION Othor than .... allng tnnovene jolnls, no major rehlbUltltton ls requlred now or over the next 20 yean. Rne1.llng may be delayed 1 few ye.rs with no advet1e effects.

PRBDICTED LIFI! OF REHABILITATION

AlttrNtlve Yun UnacCll!ptable Rettondon 20+

RESULTS OF LJFJ!.CYCLB COST ANALYSIS

Altem.atlve Rettoration

lnldal Coot

19,900

Annual Coot

1,100

Cost per 2--lane mile, hued on predicted life 1hown above (20 yean) •nd discount rate of 3 percenl

RECOMMENDED RllHABILITATION (1989) Rese1l tnnsvene Joints to conect sealant reservoir shape factor.

Reh.abllltation Technique Reseal tnuuvene joints

Quantity per 2-lane mile and shoulden.

Quandty 11372 ft

TABLE 4 RESULTS OF EXPEAR ANALYSIS OF MI 3

PAVEMENT DESIGN Highway: 1-94 near M1rshall Pavement type: 10-lnch JRCP Year ronstnlcled: 1986 Joint opadng: 41 feet Jolnt sealant: Preformed Dowels: 1.2.5-lnch diameter Reinforcement: 0.168 lnJ/ft Ba!te: 4-inch penneable untreated

Subgnde: Shoulders: Drains:

TRAFFIC Current 2-way AOT: Percent tru.cb: IA~ t:ach direction: Accumulated ESAL:

aggregate A-4 Tied PCC Yeo

31,300 22 2 2.rl ml111on (outer lane)

EXISTING PAVEMENT CONDmON (outer lane) Year surveyed: 1987 PSR: 4.8 Deteriorated cracb: O/mJle Crack faulting: 0.0 Inch Deteriorated joints: O/mlle Joint faulting: 0,02 Inch Longitudinal cracks: O feet/mile Long. joint opall: O feet Pumping: None PCC swface: Tined Joint sealant damage: Low "D" cracking: None Settlemenm/heaves: None

Shoulder condltlon: Good Lane/ ohoulder joint: Good

Ovenll: Traffic J.1nee and shoulden show no deleri.oro.tlon.

PHYSICAL TESTING Rl!COMMENDATIONS No phyalcal testlng w.,ranted.

FlTl'lllll! CONDmON wrm:our RllHABn.rTATION ServiceabUlty: Deteriorated jolnll: Deteriorated cracks: Faulting:

PSR > 3.0 over 20 years > 27 / mUe In 2D03 > 75/mlle In 1996 < 0.25 Inch ov'-r 1.0 yu .r.:.

CONSBQUBNCB OP DELAYING Rl!HABJUTATION None.

PREDICTED LIFI! OF REHABIUTATION No tthlbilUaUon needed fot al lt.u t .9 ycan..

RESULTS OP LJFJ!.CYCLB COST ANALYSIS None.

RECOMMENDED Rl!HABILITATION No rehabilitation ls needed for at leut 9 yean. At that lime, full-depth repair of joints and cn1.cb wW be needed. The pavement wn unden:letlgned for the very heny tr,lfflc on (-94.

TABLE 5 RESULTS OF EXPEAR ANALYSIS OF MN 3

PA VEMEN"I' DESIGN HJghway: ].90 near Awttn Pavemenl lype: 9-lnc:h JRCP Year coNtructed: 1984 joint opadng: 27 feet Dow11l111 1-lnd\ diameter Reinfon:ement: 0.054 lnJ/ft Base: ~Inch untreated Subg,.de: A-4 Shoulder>: AC DnlN: None

TllAPFJC Cum.mt Z.-way ADT: Pe~ent tnlcb: Lines each direction: Accumulated l!SAL:

10,600 15 2 1.S mllllon (outer Ju~)

HXISUNG PAVEMENT CONDmON (ouler lane) Year JUrveycd; 1987 PSR: 3.8 Detertonted. en.ck!: 0/mlle Crack faulllng: 0.00 inch Deteriorated )oint:s: O/m.Ue Joint faulttng: 0.1>2 inch Loogitudinal cracb: 0 feet/mlle Pumping: None PCC surface: Tined Joint tul.lnt damage: tow Mver\ty "D' craclclng: Norv: Settlemenbl/heava: None

Shoulder condition: Good t.ne/1houlder joint: Poor

Ovetwll; Only minor dol<rlontlon. A subdralluge ddkkrv:y lJ lndlcal<d by de.,. buc, lmpormoabl• oubgr>dt, lnad<qu&I<: dltd"" and hHvy tTOfA<.

PHYSICAL TESTING RECOMMENDATIONS No dtDocllon '"'~ need«! . Cori"' 11 crnltr slab. Co,. <or1mlnadon and malOrlab lt<!Wg. Including p<tmubtllty of but. No '°ughnao or •kid """"II needtd .

PUrlJRE CONDmON WITHOUI' llEHABll.ITATION Secvlc:eabtllly: Delerlont<d Jolnl!I: Deteriorated crackl: Pumping:

PSR < 3.0 In 2005 > 0.27 /mlle In 2006 > 75/mlle In 2006 Medium. In 2001

CONSEQUENCE OP DBLA YING llEHA811.1TATION Subdr1il'llge lmpmnment wouJd delay future pumping and re]ated distresset.

PREDICl'ED LlPB OP REHABILITATION (1992)

Alternative Restoration

Yean Unaccepuble 20t

RESULTS OP LIPll-CYCLE COST ANALYSIS

Altemadve Restoration

lnltlal CoBI

37,800

Annual Coat

2,200

Coot ptr l-lule mil<, tt.Jtd on predi<led Ille (20 years) and d!Jtou.nt ralf' ot 3 pc·run

RECOMMENDED REHABll.ITATION Subd.rainage Improvement would extend life of pavement.

llch&bllludon Ttclullqun hut.II oubdralns

Quantity per ~lane mile and shoulden.

Quantlly 5280 ft

TABLE 6 RESULTS OF EXPEAR ANALYSIS OF MN 2-3

lA VEMEN"I' DESIGN Highway: 1-90 near AJbert Lei Pavement type: 9-inch JRCP Year constructed: 1976 Joint spadng: 27 feet Dowels: I-Inch diameter Reinforcement: 0.097 ln2 /ft Base: 5-lnch untreated Subgnde: A-2 Shou1den~ AC Drains: None

TllAllJIIC Current 2-way ADT: 3,900 Pen::ent trucks: 20 lanes each dlrectk>n: 2 AccumuJated ESAL: 2.78 million (outer lane)

EXISTING PAVEMEN"I' CONDmON (outer lane) Yttr •urv6~; 1987 PSR: 4.0 Deteriorated cracks: O/mlle Crack faulting: 0.00 inch O.terlonted )oinll: 5/mlle Joint faulting: 0.05 Inch Longitudinal cracb: O feet/mlle Pumping: None PCC turface: Tined Joint sealant damage: Medium severity "D" cracking: None Settlements/heaYet: None

Shoulder condition: Good t.ne/1houlder joint: Poor

0vfr1U1 Tr.Inc 1u..a show some joln1 dcttricmUon and fa.ultlng. Shoulder1 are In good condition. .,...pt tht l>nel•houldet Joint.

PHYSICAL TESTING RECOMMENDATIONS O.ll<dlon t,.rlng not llHCl<d. No caring or m1te.UIJ leollng notdtd. No n>ogh,,... or 11dd lfttlng needt<L

P1111JllE CONDmON wrraour llEHABnITATION Deterlonited.joinbl: > 27/mlle in2004

CONSEQUENCE OP DBLAYING llEHABll.ITATION Joint_ datcdonitlon rt\l)' lncfUU!' If Joint 1Nl1nt i5 not tepJacfd, lb:«sslvc \v.at r NY ti\lfr Jrttion If longiludlnal lanc/1houldor Jol.nt n<>I t<ff•lcd.

PREDICTED LlPB OP llEHABll.ITATION (1992)

AJt.,naUvc lt8tona.Uon

Yu.n Unac<wpl.&ble 20+ Joint dt1ttrlo111tion

RESULTS OP LIPll-CYCLE COST ANALYSIS

Altem1dve Restoration

InllJal Con

44,500

Annual Cool

3,100

Coot p<r 2-l1n• mll•, tt...d on predlcred tile (W years) Ind discount RIO O( 3 p:.runt.

RECOMMENDED ltEHA8!UTAnON (1991) MlnQr rtstoullon work In 5 yurs may cxknd llfe of p1vement.

Rucon.Uon Tc:ehnlque full-dtplh "-P•lr jolnll Pull-depth n!pllr cr1cb Reseal tn.naverae Joints Reseal i1nc/1houlder joint

Qu1nHly per ~line mlle and thoulden.

Quantity 133 oy 2hy

'493ft 10560 ft

Darter and Hall

and quantities presented in Table 6 are for restoration work in 1992.

CA 6, Fair Condition

Table 7 presents the results of the analysis of CA 6, a section of 9-in. JPCP located on Route 14 near Solemint, California, in a dry, nonfreezing climatic zone. The pavement has carried about 4.4 million ESALs in the outer traffic Jane since its construction in 1980. When surveyed in 1987, its PSR was 3.4, it had no transverse cracking, and some joint spalling and longitudinal cracking. Faulting at transverse joints av­eraged 0.15 in. and the joints were not sealed. The PCC slab exhibited low-severity reactive aggregate distress .

As Table 7 indicates, EXPEAR predicted a relatively short life for restoration (6 years), primarily because more joint deterioration is predicted in the future as a result of the re­active aggregate. As a result, three overlay options have lower equivalent annual costs than restoration. The alternative with the lowest annual cost is a 3-in. AC overlay with sawed and sealed joints.

NC 1-8, Fair Condition

Table 8 presents the results of the analysis of NC 1-8, a section of 9-in. JPCP located on 1-95 near Rocky Mount, North Carolina, in a wet, nonfreezing climatic zone. The pavement has carried about 9.1 million ESALs in the outer traffic lane since its construction in 1967. When surveyed in 1987, its PSR was 3.3, it had some transverse cracking (20

227

per mile), some joint spalling (5 per mile), and faulting of 0.22 in. at transverse joints.

Although faulting is already high, the PSR is currently ac­ceptable, and was predicted by EXPEAR to remain above the critical level of 3.0 for another 5 years. Rehabilitation could be performed now, or could be delayed a few years. As Table 8 indicates , restoration and overlay alternatives have comparable predicted lives, but restoration has the lowest annual cost.

NC 2, Fair Condition

Table 9 presents the results of the analysis of NC 2, a section of 11-in. JPCP located on 1-85 near Greensboro, North Car­olina, in a wet, nonfreezing climatic zone. The pavement has carried about 5.8 million ESALs in the outer traffic lane since its construction in 1982. When surveyed in 1987, its PSR was 4.2, it had no transverse cracking or joint spalling, and min­imal faulting. The only noted distresses were high-severity pumping and low-severity joint sealant damage, including a drainage deficiency. As Table 9 indicates, EXPEAR rec­ommended that subdrainage improvements not be delayed. Excellent performance is predicted for restoration over the 20-year analysis period, and the annual cost is very low.

NJ 2, Fair Condition

Table 10 presents the results of the analysis of NJ 2, a section of 10-in. JRCP located on Route 130 near Yardsville, New Jersey, in a wet, freezing climatic zone. The pavement has

TABLE 7 RESULTS OF EXPEAR ANALYSIS OF CA 6

PA VEMBNT DESIGN HJghway: Roule Hi nt'.tr S!Jl~mlnt Pa.vement type: 9-lnch ]PCP Year constructed: 1980 Joint spacing: 12-13-15-14 leet Dowels: Undoweled Base: 4.2-lnch le1n concrete Subgnde: A·2 Shoulden: AC Drains: Drains present

TRAFl'IC Cunent 2-way ADT: 46,000 Percent trucks: 9.0 lanes each direction: 3 Accumulated E.SAL: 4.43 milllon (outer lane)

EXISTING PAVEMENT CONDIDON Year surveyed: 1987 PSR: 3.4 Deterlonted cracks: O/mlle Deteriorated joint!: 2/mile Joint faulHng: 0.15 Inch Longitudinal cmkJ: 51 leet/mlle Pumping: None PCC surface: Tined, not polished Joint seail1nt dam1ge: High severity (not se1led) "D" cracking: None Reacdve aggregate: LDw severity Settlement1/heave1: None

Shoulder amdltlon: Excellent Lane/1houlder joint: Poor

PHYSICAL Tl!STING RECOMMENDATIONS Corlng at reprnentltlve deteriorated tnn1vene joints. Coring at longitudinal joint ond cnck. Teat 1tr<ngth of PCC 1wf1ce and lean conaete b11e. Observe eroelon at top ol l<an concroi. boK. l'otn>graphlc exom cl PCC for OIJ8"l'lt •Hc:Hvlty.

FUflJRB CONDIDON WITHOUT RllHABil.ITATION Fau!Hng: > 0.10 Inch Jn 1987

CONSEQUl!NCB OF DELAYING RBHABil.ITATION Faulting It cunenUy unacceptable.

PREDICI'ED LIPI! OP RllHABILITATION

Alternative Restoration 3-lnch AC OL 5-inch crack/seat AC OL 3-lnch 11w/1eal AC OL 7-inch unbonded PCC OL

Yun Unacceptable 6 Jt. deterioration 8 Rutting, rf crck 9 Rutting

12 Rutting, d crck 20+

RESULTS OF LIFJl.CYCLE COST ANALYSIS

Alternative Reslonlion 3-ln<h AC OL 5-inch crack/seat AC OL 3-lnch saw /seal AC OL 7-inch unbonded PCC OL

lnlUal Coot

248,800 312,900 406,800 335,800 619,400

Annual Cost

43,300 42,000 49,200 31,800 39,200

Cost per 2-Jane mile, hlted on predicted Jlvet shown above (20 ye.n for unbonded overlly) and dlscount n.te of 3 percent.

RECOMMBNDED RllHABil.ITATION (1989) 3-lnch AC overl1y wJth 11wed and se.Jed Jolnts Js the most costo4i!ffectlve 1llem1tlve, wlth a life of about 12 years.

Rchablllt.atlon TechnJque Pull-deplh ,..,.;,of jolnll Full-depth repair of crack! Reseal tnn1vene Jolntl Reoeol ione/1houlder joint 3-lnch ,.w /1eol AC OL

Quantity per 2-lane mile and ahoulden.

Quontlty 434 ay 10 •y

9910 ft 10560 ft 22293 •y

TABLE 8 RESULTS OF EXPEAR ANALYSIS OF NC 1-8

PA VBlllllNT DESIGN Highway: la95 near Rocky Mount Pavement type: 9-lnch )PCP Year comtructed: 1967 Joint •pacing: 30 feet Dow1l11 Undowclcd Bue: 4-ln<h unl1Ulod aggregalt Subgiade: A-2 ShouldetB! AC DnlN: No dralN present

TRAFFIC Current 2-way ADT: Percent trucks: Linea each direction: Accumulated ESAL:

19,100 9.0 2 9.14 mllllon (outer line)

EXISTING PAVEMENT CONDmON Ye1r surveyed: 1987 PSR: 3.3 Delerlontod cncb: 20/mlle Deterlonted jolnl>: 5/mlle joint faulting: 0.22 inch Longitudinal cracks: 0 feet/mile Pumping: None PCC 1urface: TJned, not polished Joint sealant dam1ge: Low severity -0" cracking: None Reactive aggregate: None Settremenbl/heaves: None

Shoulder condition: Good Lane/shoulder jolnt: Poor

Overall: Excessive faulting indicates a load transfer defld enc)'. Some joint and crack deterioration present, redudns .t:(lnilct1• bUlty.

PHYSICAL TESTING RECOMMENDATIONS Defledlon test for structure an1lysU and void detection. Core at center of slab to obtain material samples. Core representative deteriorated. joints. Test strength of rec cores.

FlTl'UllE CONDmON wrmovr RBHABD.ITATION S.n1J0Hb1lllyl F•ultlng' )olnt detoriont\on: C.-a.:1JJ13,

PSR < 3.0 In 1994 > 0.10 Inch In 1987 5/mlle for 2D yean 24/ mil• In 20 yean

CONSBQtJENCB OF DELAYING RBHABRJTATION Faulting Lt atn.ady high, but PSR la ntod above 3.0. A few yean of delay can be talented.

PREDICl1!D UPB OF RBHABn.ITATION

Alternative Restontlon 3-lnch AC OL

Yun 14

Unacceptable Faulting

fl.Inch cnck/seat AC OL ~nch &aw/teal AC OL 7-lnch unbonded PCC OL 11-lnch ~mtn.ictton

10 14 15 20. 2D•

Rel. cncldng Ref. cncklng Ref. er.eking:

RF.SUL'IS OP IJFE-cYCLE COST ANALYSIS

Alternative Restondon 3-lnch AC OL 5-lnch cr1ck/ se1t AC OL 3-inch saw /seal AC OL 7-lnch unbonded PCC OL 11-inch reconstruction

lnldal Coll

1°',000 303,000 '28,000 313,000 635,000 506,000

Annual Coit 6,000

28,900 23,100 21,400 30,200 29,300

Cost per 2-llne mile, based on predicted lives shown above (20 years for unbonded overlay and reconstrudlon) and discount rate of 3 percent.

RECOMM'l!NUiiO REHABILITATION (UH) Technlqu< QuanOly Crlnd Ing '1040 •Y f ull•chplh rcp&lr o( '-Y•Cb 210 ty Full-<lepth r<palr ol Joints 80 •Y Rir1e11111n.sve:SM: Jol.nt1 i1:106 n Reseal lane/shoulder joint 10560 ft

Quantity per 2-lane mile and shoulden.

TABLE 9 RESULTS OF EXPEAR ANALYSIS OF NC 2

PAVBllll!NT DESIGN Hf3hway: 1-85 neat Clftnsboro Pavement type: 11-lnch )PCP Year constructed: 1982 joint opacing: 19-lfl.25-23 feet Dowela: Doweled, 1.38-lnch diameter Bue: 5-lnch lean concrete Subgnde: A-4 Shoulder., 11..S PCC DnlN: Drains present

'l'RAJIPIC Current 2-way ADT: Percent trucks: Linet each direction: Accumulated ESAL:

26,000 17.0 2 5.76 mllllon (outer lane)

EXISTING PAVEMENT CONDmON (outer lane) Year .surveyed: 1987 PSR: 4.2 Deterlonted en.ck.I: 0/mlle DetertoAtod jolnl>: O/mlle Joint faulttng: 0.02 Inch Longitudinal crocks: O feet/mile Pumping: High PCC surface: Tined, not polished Joint sealant damqe: Low severity "D' cracldng: None Reactlve aggregate: None Settlements/he.vee: None

Shoulder condition: Excellent lane/shoulder joint: Poor

Overall: Although drains are present, high-severity pumping Indicates a drainage deficlency.

PHYSICAL TESTING RECOMMENDATIONS Deflection test slab comen for void detection. Core at ctntq-r uhJ1b to obt.t ln tr\llttl1l n mplt1. FJr:11mh"lf' ~tablUud ba!t!: l:Orcs lorero1lon. P.:valuate dnln.abillty (gnd•llon, p<rmo1blllly) ol 1u1>gr•d•.

FlTl'UllB CONDmON wrmour RBHAllRJTATION Setvl«•blllty: Faulllng: Jo!nt delt'riontlon: Cncldng:

PSR = 3.0 In 20 y<OIS < 0.10 Inch for 20 )~Us O/mlle for 20 ~·an 7/mile In 20 ye1m

CONSEQtJENCB OP DELAYING REHABILITATION Subdralnage and slab support improvements art required now.

PRBDICl1!D LIFE OP REHABRJTATION

Altematlve Reator1tlon

Yun Unacceptable 2D+

RF.SUL'IS OF LIFll-CYCLE COST ANALYSIS

Allematlve Restoration

Inldal Coot

29,300

Annual Coot

1,900

Col l pe r 2.-l.l nc mil'- l»5ed on predicted llfe shown above (20 yeAn) and dlstount r1.te of 3 pen::ent.

RECOMMENDED REHABILITATION (1989) Technlqv• Quanttty Repo.lr longitudinal subdral~ 5280 ft Su\Ral at join ts 208 cf grout R~al Jane/ sho ulder joints 10560 ft

Quantity per 2-lane m.lle and shoulders,

Darter and Hall 229

TABLE 10 RESULTS OF EXPEAR ANALYSIS OF NJ 2

PA Vl!Ml!NT DESIGN Highway: Route 130 near Yardvllle Pavement type: 11).lnch JRCP Year con1tructed: 1951 Joint •peeing: 78 feet Jolnt tealant: Expt.nslon Dowel diameter: 1.25-lnch 1t1lnless steel clad Reinforcement: D.168 ln1/ft BHe: $.Inch untttl.ttd •ggrtg.tlr Subgnde: A~ Shoulde,.: AC DralN: None

TRAFFIC Cunent 2-way ADT: Percent truck!: Lanes eaich direction: Accumulated ESAL:

24,650 22 2 34.8 million (outer lane)

l!XISTING PAVEMENT CONDmON (outer lone) Year 1urveyed: 1987 PSR: 3.8 Deterlonted cncb: 24/mlle Crack faulting: 0.02 Inch Deteriorated joints: 14/mile Joint faulting: 0.06 inch Longitudinal cncks: 10 feet/mile Long. Joint spall: 141 .. t Pumping: None PCC surface: Not polished Joint sealant damage: High severity "IY cracklng: None Settlements/heaves: None

Shoulder cond I ti on: Good lane/shoulder Joint: Good

Overall: Some transverse crack and Joint detertontton. Some faulting at joints and cracks. Shoulden; are in good condition. Subd.r.lNge deftdency indicated due to dense-graded aggregate bi15e, A-4 subgrade, inadequate ditch depth and heavy b'affic. Joint sealant ls in poor condition.

PHYSICAL TESTING RECOMMENDATIONS Deflection testing needed for structural analysis and void detection. Coring and materials testing needed for assessing extent of deterioration, Materials testing for base permeability.

carried about 35 million ESALs in the outer traffic lane since its construction in 1951. When surveyed in 1987, its PSR was 3.8, it had 24 deteriorated transverse cracks per mile, 14 de­teriorated joints per mile, and some faulting at cracks and joints. High-severity joint sealant damage was also noted.

On the basis of the observed distress and heavy truck traffic, EXPEAR predicted that the pavement's condition would re­main acceptable for only another few years. As Table 10 indicates, restoration in 1989 would have the lowest annual cost of all of the alternatives, and predicted life of 8 years. If rehabilitation were delayed beyond that time, overlay or re­construction options would probably provide lower annual costs and better long-term performance.

CA 1-3, Poor Condition

Table 11 presents the results of the analysis of CA 1-3, a section of 8.4-in. JPCP located on 1-5 near Tracy, California, in a dry, nonfreezing climatic zone. The pavement has carried about 7 .6 million ESALs in the outer traffic lane since its construction in 1971. When surveyed in 1987, its PSR was 3.0, it had 30 cracks per mile, 10 spalled joints per mile, and 500 ft of longitudinal cracking per mile. Faulting at transverse joints averaged 0.10 in., the joints were not sealed, and medium­severity pumping was evident. The PCC slab exhibited low­severity reactive aggregate distress.

Because the condition of the project is already unaccept­able, rehabilitation should not be delayed. As Table 11 in-

FUl'tlRB CONDmON WllHOur REHABILITATION Servlceablllty: PSR < 3.0 In 2003 Deterto .. ted jolnb: > 27 /mile In 1990 Detertonted mdai: > 75/mlle In 1989

CONSEQUENCE OF DBLAYING REHABILITATION Th1J Is 1 very old pavement th.It haa carried a large amount of tnfflc and la now deterlocatlng (a1e:ldng1

jolnt deterlon.tlon and faulting). The pavement has some potential for restoration If done soon.

PREDlClllD UFE OF REHABILITATION

Alternative Yesn Unacceptable Restoration 8 Joint/crack

deterioration 3-lnch AC OL Ref. cracking,

rutting 5-incli crack/seat AC OL 10 Rutting 9-lnch unbonded PCC OL 14 Jt dttt'.riontion,

cracking 12-lnch recorutruction 20 Jtdeterlcration,,

cracking

RESULTS OF LIFE-CYCLE COST ANALYSIS

Inlti•I Alternative Coit Restoration 182,000 3-lnch AC OL 423,900 5-lnch crack/seat AC OL 488,300 9-lnch unbonded PCC OL 730,000 12-inch recomtructlon 6181800

Annual Coat

24,400 73,800 54,000 60,900 42,700

Con per 2-lane mile, hl.s.M on pttdlcted Dvcs ind dlJC'ount r11c of 3 perccnL Slnce ahould(lrJ" U1: Jn good condition, shoulder removal and replacement not included in cost of recorutruction.

RECOMMENDED REHABILITATION (1990) The restoration alternative ls the most cost-effective. If a life of 8 yean la acceptable, restoration is recommended. If not, recorutructlon Is recommended.

Restoration Tir:chnlquee Full-depth repair joints Full-depth repair cracks Reseal transverse joints Install subdn.ins (both lanes)

Qu•nH!y 337 sy 701 sy

1108 ft 10,560 ft

dicates, the annual cost of restoration is similar to that of an unbonded overlay or reconstruction, but the predicted life of restoration is fairly short. A significant unknown is the rate of progression of reactive aggregate distress in the concrete. Coring, strength testing, and petrographic examination of the concrete were recommended by EXPEAR to assess the ag­gregate's reactivity. Restoration is recommended only if the reactive aggregate distress is not projected to progress further. Otherwise, an unbonded PCC overlay or reconstruction is recommended.

MI 4-1, Poor Condition

Table 12 presents the result of the analysis of MI 4-1, a section of 9-in, JRCP located on 1-69 near Charlotte, Mich­igan, in a wet, freez.ing climatic zone. The pavement has car­ried about 4.4 million ESA in the outer rraffic lane since it construction in 1973. When surveyed in 1987, its PSR was 2.4, it had extensive transverse crack deterioration (222 per mile), moderate faul ting (0.08 in. at cracks, 0.12 in. at joints), and medium-severity joint sealant damage.

The pavement need immediate rehabilitation. As Table 12 indicate , restoration is a poor rehabilitation choice, in terms of both performance life and annual cost. The crack and seat AC overlay, saw and seal AC overlay, and bonded and unbonded PCC overlay options are all very close in pre­dicted life and annual cost.

TABLE 11 RESULTS OF EXPEAR ANALYSIS OF CA 1-3

PA VllMENT DESIGN HJghway: 1·5 near Tncy Pavement type: 8.4-inch JPCP Year constructed: 19'71 Joint 'P'dng: IZ.-U-19-18 feet DnwPl1t: t Jnrtowtled Bue: 5.4-lnch cement.treated Subgnde: A-1 Shoulden: AC Dnim: No dnlM present

TRAFFIC Current 2-way ADf: Petcent trucb: Lanes each dlrectlon: Acrumulated F.SAL:

13,000 19.0 2 7.62 million (outer lane)

EXISTING PAVl!Ml!NT CONDmON Year surveyed: 1987 PSR: 3.0 Deterior.ted cncb: 30/mlle Deterionted Joints: JO/mile Joint l1uldng: 0.10 Inch Longitudinal cracks: 500 feet/mile Pumping: Medium rec 1ur{1C,., lined, not polllht'<I Jotn.1 ae1?.tnt damage: Hlgh 1111\.'(rtty (not aealed) "D' mcklng: N no Reactivt! •88ft8.•~ Low ;everity Settkmrntt/huve.: None

Shoulder condll:ion: Excellent 1.ane/ahoulder jolnl: Poor

Cmu•ll: Slgnl&.nt Joint dotorlotodon. • lob ""'cklng ind Joint f1utdng awes rvughn • Subdrahuge dtlklmcy <'Xlsbl.

PHYSICAL TESTING RECOMMENDATIONS OtOcdlon te,t for 1tructurc anal)'l~ tnd -void dett<:tton. Cott rec sum~ anH 1t.1.bi llzed hlse at c:entf'r of 1l&b. Cott rtpmtntatl\le deteriOl"ll.rd }olnts and cracb. Core longlh.idlnil joint •nd (rtCk. Test ttrength of PCC 1urfl.ce •nd •l•bll17.Rd ba11e. evalu1te dtslNblllty (grod1Hon, pcrnvabillty) ol 1ubgrtdt. Pt-1rognphlc rx•m of rec tor •ggreg•te n:act!vlly.

FUTURE CONDmON WITHOUT REHABILITATION Servlce1blllty: PSR = 3,0 In 1987 P1ultlng: 0.10 inch In 1987 Pumping: Medium In 1987

CONSEQUENCE OP DELAYING REHABIUTATION Condition II curTently u111cceptable.

PREDICTED LIFE OF REHABILITATION

Alternative hstoratlon 3-lnch AC OL 5-lnch crack/seat AC OL 7-inch unbonded PCC OL 9~11\Ch 11'COru1tucdon

Yun s 8

10 211+ 211+

Unaucptlble Jt.. de.lt.rlor•tfon R<r. cracking Rutting

RESULTS OP LIFE-CYCLE COST ANALYSIS

Altem1tlve Restonitlon 3-lnch AC OL 5-inc:h crack/seat AC OL 7-lnch unbonded PCC OL 9-lnch recorutructlon

lnidal Coot

180,000 419,000 442,000 600,000 603,000

Annual Coll

37,100 116,300 48,800 38,000 38,200

Cati pctr 1-lan~ mile, bl•i:d on predicted lives shown 11tbcv~ (20 yeari for unhanded ovtrl•)' and reconstrudlon) •nd discount rate of 3 percent.

RECOMMl!NOEO REHABILITATION (US9) Re1lo~ only Ir pt"trognphk 1n1Jyall lndk1t~ low •gg~alt reactivity. 01huwlle, overl1y with unboncftd PCC or rttONll'\Kt.

RehabUludon Technique Full-depth repair de,.rtoroted joints Pull-depth reP"lr detertonted Joints Reseal tnn1verse )oinbl Sul longitudinal crack& Reoe1l llne/1houlder Joint INtall 1ubdralns

Quantity per 2-J.ne mile and 1houlden.

Qulndty 'JJYlsy 634 •y

10440 It 940 It

10560 It SlJ!O It

TABLE 12 RESULTS OF EXPEAR ANALYSIS OF MI 4-1

PAVEMENT DESIGN lllghway: I~ near Chulotte Pavement type: 9-inch JRCP Year constructed: 1973 Joint spacing: 71 feet Joint 1e1l1nt: Prefonned Dowel dlameter. 1.25 ln Reinforcement: 0.162 ln1 I ft Base: 4-lnch untreated aggregate Subgnide: A~ Shouldera: Tied rec Drains:

TRAFFIC Current 2--way AUT: Percent trucb: r.,,,,., .. ch dittctlon: Accumulated ESAL:

None

13,700 II 2 4.37 million (out<r lane)

EXIS'llNI> PA VBMllNT CONDmON (outer lane) Year survtytd: 1987 PSR: 2.4 Detertonted cncb: 222/mlle Crack faulting: 0,08 lnch Deterlo,.ted Joints: O/mlle Joint !1ulHng: 0.12 Inch Longltudinll cnckl : 0 leet/mlle Long, joint •P"ll: o leet Pumping: None PCC surface: Tlned Joint 11e1l1nt damage: ~lum 1ever1ty "D" craclci11g: Low Settlementl/heavea: None

Shoulder condldon: Good Lane/1houlder joint: Good

Ovenll; Traffic lines 1how extensive trlMvene crack dticrlor1lloftt but no jalnl dctcrtontion. Somt faulU1'4 •.Ult 1t lolnlt 11"1 <n<I". Shoulder> .... in good con<lldQI\. Subdr1IN&• d<fkl<ncy lndlcatt'<I by deMo­gr>ded '83~•,. bcH, A~ 1ubgndt, lnadf<!ualt dlt<h dtpth 1n<I ht•vy tralllc.

PHYSICAL TESTING RECOMMENDATIONS 0.Ut<llon !<>ling ne<ded for alNctursl 1noly>ll and void dt lrd.lon. Coring .and 1JU1rerl1lt ttttlna MftiC'd lot asaeutng VdetPl ol ddf'riontlon (ram •o· a-.-cklng (boch .......... Ind longltod lNI joint>). Mol<rl•IJ ,..«"41 for 1•>rrneablllty.

FUTURB CONDmON WITHOUT REHABILITATION Servlce1blllty: Deterlorsted Joints: Deteriorated crackJ:

PSR c 3.0 In 1987 > 27/mlle In 1997 > 75/mlle In 1987

CONSEQUENCE OF DELAYING REHABILITATION P"avHntti1 II 11tt1dy v.iry nJugh and nttd• bnmcdi1r~ ft'habllltatlon. l\ll lyptf of d•ltriontlon 1tt pr<dl<!td to lncniut lri Ntv"1. Pavt-rMnt la too dtleriorattd far retoraUon now. AC OYfrky may not be fe11lble due IO d•ttr!ondon ol rec >lob.

PREDICTED LIFE OP REHABILITATION

AltematJve Res ton ti on 3-lnch AC OL !I-Inch atck/seat AC OL 3-lnc:h 11w/1eal AC OL 3-lnch bonded PCC OL 7-lnch unbonded rec OL

Yun 5

10 15 13 15 17

Vnoccepllble Jt. deterioration R<I. crocking Rutting Rel. a.eking Ref, cncklng Jt deterlorwtlon, en eking

RES UL TS OF LIFB-CYCLE COST ANALYSIS

Altematlvit Raton ti on 3-lnch AC OL 5-tnch aock/1eot AC OL 3-lnch llW/Hll AC OL 3-lnch bonded PCC OL 7~nch unbon<led PCC OL

lnllW Coot

718,7ll0 611,900 736,400 621,600 706,100 '1118,7ll0

Annual Coot

143,'°° 67,600 511,100 55,100 55,800 55,7ll0

Coot per Z-lln• milo, ~ on p...SlcVd llveo 1hown above and dl6coun.t rat• ol 3 pctto11l,

RECOMMENDED R'EllABIUTATION (1'ff) Tlutt 1llm\IUY .. (3-inch llW/N~l l\C 01. Sob:h bonded PCC 01. 7·1nch unbonded rec OL) ... •try 1lrnli.t In perfo<ml- 1.nd -L l'wtlwr INl)'lll II ,.,....ed rw Hl«tton.

Darter and Hall

MI 1-IOb, Poor Condition

Table 13 presents the results of the analysis of MI 1-lOb, a section of9-in. JPCP located on US-10 near Clare, Michigan, in a wet, freezing climatic zone. The pavement has carried about 0.9 million ESALs in the outer traffic lane since its construction in 1975. When surveyed in 1987, its PSR was 2.8, it had extensive joint deterioration (219 per mile) , faulting of 0.19 in. at joints, extensive longitudinal joint spalling (1,395 ft per mile), low-severity pumping, medium-severity joint sealant damage, and medium-severity D cracking.

As Table 13 indicates, the pavement has too much dete­rioration for restoration to be cost-effective. An unbonded PCC overlay is the best rehabilitation choice in terms of per­formance and annual cost.

MN 1-8, Poor Condition

Table 14 presents the results of the analysis of MN 1-8, a section of 9-in. JRCP located on I-94 near Rothsay, Minne­sota, in a dry, freezing climatic zone. The pavement has car­ried about 5.5 million ESALs in the outer traffic Jane since its construction in 1970. When surveyed in 1987, its PSR was 3.4, it had extensive crack deterioration (102 per mile), joint deterioration (141 per mile), and longitudinal cracking (1,775 ft per mile). Faulting at transverse joints averaged 0.09 in . Low-severity D cracking and joint sealant damage were also noted.

The pavement's condition is currently unacceptable. As Table 14 indicates, the rehabilitation strategies with the lowest

231

annual cost are reconstruction and unbonded PCC overlay. Because no preoverlay repair is involved (i.e., increases in distress quantities do not affect strategy cost), either recon­struction or an unbonded overlay could be delayed a few years. Despite the large amount of distress present , rideability is still acceptable, so some delay in rehabilitation could be tolerated.

SUMMARY

The pavements examined here that were in g od condition had minor faulting (average of 0.02 in .), little or no joint spalling or load-related cracking, and good ride quality (PSR greater than 3.5) . For these pavements, restoration was con­sistently the most cost-effective rehabilitation strategy.

Pavements in fair condition had greater faulting (average of 0.11 in.), moderate joint spalling (average of 5 joints per mile) and load-related cracking (average of 11 cracks p r mile) , and fair ride quality (PSR great.er than 3.0) . Resto­ration was the mo t cost-effective rehabilitation trategy for four of the five case studies in fair condition. The exception was a pavement that had joint deterioration because of re­active aggregate .

The pavements in poor condition had high levels of fau lting (average of0.13 in .) , a large number of spalled joints (average of 92 per mile) and load-related cracks (average of 88 per mile), and poor ride quality (PSR of 3.0 or less) . In every case examined, overlay or reconstruction was more cost­effective than restoration .

TABLE 13 RES UL TS OF EXPEAR ANALYSIS OF MI 1- lOb

PA Vl!Ml!NT DESIGN Highway: US 10 near Clare Pavement type: 9-lnch ]PO' YeAr conatn.icted: 19'75 )olnt opadng: 1~19-lS.12 feet Dowels: Undoweled Relnfon::ement: None Base: ~Inch aspNlt-treated Subgr.tde: A-2 Shoulder.: AC On ins: None

TRAFFIC CWTent 2-way AOT: 5,100 Percent trud.9: 8 Lanes each direction: 2 Accumul11ed ESAL: 0.88 million (outer lane)

EXISTING PAVEMENT CONDmON (outer lane) Year surveyed: 1987 PSR: 2.8 Deterior1ted cr.tclc.s: O/mile Crack faulting: 0.00 inch Deteriorated joints: 219/mlle Joint faulling: 0.19 inch Longitudlnal cracks: 0 leet/mlle Long. jolnt spall: 1395 feet Pumping.: Low PCC surface: Tined Joint sealant damage: Medium severity "D" cracking: Medium Settlements/heaves: None

Shoulder condition: Good Lane/ shoulder joint: Good

Overall: Traffic lanes show exlenslve joint deterioration from •o• cracking. Serious faulting f.)tl;n::s. Should~n 1n: in good condition.

PHYSICAL TESTING RECOMMENDATIONS Det1ectlon lesdng needed loc structural analysis and void detedi.on. Coring and materials testing needed for assessing extent of deterioration from "D" cracking (both transverse and longitudinal jolnbi). No roughnes.1 or skid testing needed.

PUl'IJllE CONDmON WITIIOUT llliHABILITATION S.rvlc .. blUty: PSR < 3.0 In 1981 l\tulll.., > 0.10 Inch In 1987 Dettrio,.t<d join,.: > "/mile In 1\187

CONSEQUENCE OP DBLAYING REHABILITATION Pavement too deteriorated for restoration. Tnmverse and JongltudlN1 Joint d'tuiontJon wlli inaY:.He. AC overfly may not be feulbl~ duin to dettrlor11lon of PCCslab.

PREDICll!D LIPl! OP REHABIUTATION

AlterNtlve Restoradon ~Inch AC CL 7-lnch unbonded PCC OL

Yun Un..:cept.abl• !I Jt detl!rioration

17 Ref. crocking 20+

RESlJLTS OP LIFE-CYCLE COST ANALYSIS

Alternative Restoration ~lnchACOL

7-lnch unbonded PCC OL

Initial Coot

718,200 929,500 567,400

Annual Coll

143,500 6 .. 600 34,900

Cost per ~lane nUle, based on predicted lives shown above and dlscount rate of 3 percent.

RECOll{MENDED REHABILITATION (1991) 7-jnch unbonded PCC overlay with no additional rt'lpllr ls the tnQSt cml-coffective 1ltcrR1tlvt. due lo

h.1n1lve tep.-11' n.ttdN for other alhtmatl"es·

Rehablllti.tion Technlque1 Unbonded PCC OL traffic lanea AC OL 11hou1ders

Quantity 1._080 sy 8,800 •y

232 TRANSPORTATION RESEARCH RECORD 1307

TABLE 14 RESULTS OF EXPEAR ANALYSIS OF MN 1-8

PAVEMENT DESIGN Highway: 1-94 near Roth.\ay Pavement type: 9-lnch JRCP Year consttucted: 1970 Joint spacing: Dowels: Reinforcement: Base: Subgrade: Shoulders: Drains:

TRAFFIC

27 feet t-\nc'h d\amPh>r 0.097 sq In I ft 5-lnch aspha1t-treated A-2 AC None

Current 2-wa.y ADT: 5,000 Percent trucks: 21 Lanes each direction: 2 Accumulated ESAL: 5.5 million (outer Jane)

EXISTING l'A VEMENT CONDffiON (outer lane) Year sul"\"l'!)'t'd! 1987 PSR: 3.4 Deteriorilled cracks: Crack faultlng: Deteriorated joints: Joint faulting: Longitudinal cracks: Pumping: PCC surface: Joint &callnl diamage: ·o~ cra.ddng: S.:.utomants I hc.a.,res:

102/mile 0.00 inch 141/mllc 0.09 Inch 1175 feet/mile None Tined Low severity low•verily None

Shoulder condition: Good Lane/shoulder joint: Good

Overa11: Traffic lanes have a large amount of deteriorated transverse and longitudinal cracks and joints.

PHYSICAL TESTING RECOMMENDATIONS Oo0«11on letting tor Alru('tur,.1 ana1y.i1J 4nd vold dctttdt>n. Coring 1t ccn\c-r tl.1b1 mar lranto . Jolnlt and lonsh11dlnal jolnl5. Coro ~mln.11Jon 1.nd ltUl lt"rials testing.

The cost of rehabilitation is strongly tied to pavement con­dition, as follows:

Average Initial Cost Average Annual Cost Condition Per Lane-Mile ($) Per Lane-Mile ($)

Good 32,000 2,000 Fair 163,000 16,000 Poor 605,000 45,000

It pays, therefore, to maintain pavements in good condition and to rehabilitate them before they exhibit substantial distress.

In the case studies examined, an AC overlay with sawed and sealed joints was usually the most cost-effective AC ov­erlay option. A 3-in. AC overlay with sawed and sealed joints was predicted to last longer and be more cost-effective than a conventional AC overlay of the same thickness. A 5-in. AC overlay of cracked and seated pavement typically was pre­dicted to perform better than a conventional 3-in. AC overlay. However, the cost of cracking and seating and the cost of the additional 2 in. of AC resulted in a higher life cycle cost about half the time.

The unbonded PCC overlay provided the longest life of all overlay alternatives and was found to be cost-effective when the existing pavement was badly deteriorated. Reconstruction was cost-effective if the existing pavement exhibited extensive deterioration and the shoulders were in good enough condi­tion that they did not need to be replaced.

FUruRE CONDmON WITHOUT REHABnITATION Scrviceablllty: PSR < 3.0 in 2004 Deteriorated joints: > 27/mlle in 1987 Deteriorated cracks: > 75/mlle in 1987

CONSEQUENCE OF DELAYING REHABilJTATION Joint dc1:trtora1lon •-nd crack deterioration are a1n:ally unn.a:ept1ble. Further delty ln rehabltitailon would substantially increase maintenance cost and the cosl of n!habilitation.

PREDICTED LIFE OP REHABILITATION (1992)

AltemaUve Restoration 3-lnch AC OL

Yean Unacceptable 6 F1uhing

10 Rutting, ref. cracking

7-lnch unbonded PCC OL 16 Jt. deterioration 9-inch reconstruction 20+

RESULTS OF LIFE-CYCLE COST ANALYSIS

lnlUal Alternative Cost Restoration 599,000 3-inch AC OL 748,000 9-lnch reconstruction 633,600 7-inch unbonded PCC OL 704,000

Annual Cost

104,000 83,000 42,600 52,900

CCKI per 2-1ane milt>, bind Un pn:dlcte:d Jives shown above (20 years for rt'<OtUlrucUon) and discount rale of 3 percent.

RECOMMENDED REHABnrrAnON 11992) ReconslruC'tlDn hH lowest annual ((!Sl; unbonded rec overlay also provides acceptable life at low annual cost.

Rehabilitallon TechnJques

Reconstruct both traffic lanes Reconstruct AC shoulden

Quantity per 2-Jane mile and shoulden.

Quantlty

14,080 sy 9,387 sy

Overall, the EXPEAR program provided realistic evalua­tions, future predictions, and selection of alternatives for the case studies.

ACKNOWLEDGMENTS

The research reported in this paper was part of a study entitled "Performance/Rehabilitation of Rigid Pavements" conducted for the FHWA by ERES Consultants, Inc., of Savoy, Illinois. The contract officer's technical representative for the study was Roger Larson. Kurt Smith and Sue James of ERES Con­sultants are gratefully acknowledged for their assistance.

REFERENCES

1. M. J. Darter, E. J. Bnrcnberg, and W. A. Yrjanson. CHRP l?uporr 281: Join/ Repair Methods for Portland C11mvnt Concrete Pavements. TRB, National Research Council, Washington, D.C., 1985.

2. ERES Consultants, Inc. Techniques for Pavement Rehabilitation. Participants' Notebook, 4th ed., National Highway Institute and FHWA, U.S. DcpHtment of Transportation, 1987.

3. Concrete Pavement Restoration-Performance Review. Pave­ment Division and Demonstration Projects Division, FHWA, U.S. Department of Transportation, 1987.

4. M. B. Snyder, M. J. Reiter, K. T. Hall, and M. I. Darter. Re­habilitation of Concrete Pavements, Volume I-Repair Rehabil­itation Techniques. Report FHWA-RD-88-071. FHWA, U.S. Department of Transportation, 1989.

Darter and Hall

5. M. l. Darter, J . M. Becker. M. B. Snyder, and R. E. Smith. NCHRP Repol'I 277: Co11cre1e P11 veme111 Eva/11111io11 Sys1e111 (COPE ). TRl3. National Research uncH , Washington, D. ., 1985.

6. K . D . Smith. D. G. Peshkin . M. l. Darter, A. L. Mueller, and . H. Carpenter. Performance of Joi11111d oocre10 Pn Peme111s,

Vof!lme l - £va/11a1io11 of 011cre1e l'nve111e111 l'erfomumcli m1 Design Fea111re . Report FHWA-RD-89-136. FHWA , U.S . De· panment of Transportation, 1989 ..

7. K. T. Hall , J. M. onnor. M. I. Darter. S. H . Cnrpenter. Re· habiliu11/011 of 011cre1e Pt1ve111e111 , Vo/11111c Ill - Co11 rete Pave­me111 £1111l11fllio11 mul Relwbilitfllio11 ystem, Report HWA-RD·

-073. Fl-IWA. U.S. Department of Tran p nation. 1989. 8. M. I. Darter. and K. T. Hall . S1r11c11.1ral 011er/ay S1ra11:-ie for

Joimetf Concrete Pavcme111s, Volume fll-011ideli11es for the Se­lection()! Relwbili1111io11 Aliematlves. Report FHWA-R D-89-145. FHWA. U.S. Department C>f ransportation, 1989.

233

9. K. T. Hall. M. l. Darter, •. H. arpcnter, and J . M. onnor. Development of a Demon trntion Prototype o.ncrete Pavement Evaluation ystcm. In Tmnsporra1io11 Research Record 1117, TRB, National Research ouncil, Washington, D . . 19 7.

10. K. T . Hall J . M. Connor. M. I. Darter. and S. H. arpcnter. Development of an Expert System for oncnHe Pavemem Eval­uation aDd Rehabilitation . Proc .. 2nd North A111erica11 Co11fer­ence on Managing Pavements, Toronto, Ontario, Canada, Nov. 1987.

11. K. T. Hall , J . M. onnor, M. I.. Daner and S. H. Carpenter. Expert Sy. tem for Concrcre Pavement Evaluation and Rehabil­itation. In Tra11spor1n1io11 /fr enrc/1 Recor<l 1207. TRB, National Research Council, Washington, D.C., 1988.

Publication of this paper sponsored by Committee on Pavement Rehabilitation.