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42 locations of the distresses within the pavement structure, and limit values define the point at which the pavement is in the operational impacts (functional or structural) of the dis- need of major structural improvements. tresses. For instance, a treatment whose primary purpose is to Table 3.14 (p. 58) shows the basic decision support matrix seal surface cracks and rejuvenate the HMA surface layer, would (treatmentdistress matches) presented in the preservation be a good candidate for a pavement that has become oxidized workshop manual. It is supplemented with more specific and has consequently developed considerable amounts of information regarding the suitability of some treatments low- to medium-severity cracks. for different distress severity levels. It should be pointed out A number of decision support matrices and trees were iden- that the unshaded columns in this table depict the preserva- tified in the literature, ranging from simple routines involv- tion treatments covered in the SHRP 2 Renewal Project R26 ing a few treatments and several key distress types to complex study, whereas the shaded columns represent rehabilitation algorithms featuring many treatments and an array of distress treatments. types, severity levels, and extents. As noted by Hicks et al. (2000), both tools can be used effectively in the selection Survey Results on Treatments and Deficiencies and identification of suitable preservation and rehabilitation treatments. Tables 3.15 and 3.16 (pp. 6061) reflect the state of the practice For the guidelines produced in this study, it was determined for treatment use by transportation agencies based on exist- that a decision support matrix should be used as the basis for ing pavement surface conditions. In these tables, "extensive" identifying candidate preservation treatments based on pave- use means that two-thirds or more of the highway agencies ment condition. A decision support matrix provides users with reported using a particular treatment to address a certain a more systematic and understandable approach; however, pavement deficiency. "Moderate" represents use by between decision trees could also be easily constructed from the formu- one-third and two-thirds of the agencies, whereas "limited" lated decision matrix. represents use by less than one-third of the agencies. Decision Support Matrixes Guideline Decision-Support Matrixes for HMA-Surfaced Pavements The treatment application information presented above, Three of the more comprehensive decision support matrixes representing both best and current practices, was used to prepared for HMA-surfaced pavements are illustrated in Tables formulate decision-support matrixes for identifying feasible 3.5 through 3.7 (pp. 4346). Each of these tables provides an treatments based on existing pavement condition. Tables 3.17 indication of treatment suitability for different types of distress. and 3.18 (pp. 6265) show the guideline matrixes developed In addition, Tables 3.5 and 3.6 give indications of treatment for HMA- and PCC-surfaced pavements, respectively. These suitability corresponding to different distress severity levels. matrixes are a key part of the treatment selection framework These and other similar matrixes and trees have served as a basis and process presented in Guidelines for the Preservation of for the development of preservation guidelines in various states High-Traffic-Volume Roadways. and provinces, including California, Illinois, Ohio, Montana, Nebraska, New York, Virginia, Alberta, and Ontario. Tables 3.8 Final Analysis of Treatment through 3.10 (pp. 4853) show the decision support matrixes Feasibility: Consideration of developed by the California and Illinois DOTs. Tables 3.11 and Project Needs and Constraints 3.12 (pp. 5455) illustrate the Ohio DOT's matrixes for flexible and composite pavements, respectively. Once a preliminary list of feasible treatments has been developed based on existing pavement conditions, further evaluation is needed to determine which of the treatments Decision Support Matrixes largely satisfies the needs and constraints of the project. The for PCC-Surfaced Pavements needs center on the targeted or required performance of the The FHWA's Concrete Pavement Preservation Workshop preservation activity and the impacts that various project Reference Manual (Smith et al. 2008) provides detailed and site location factors can have on the performance of the guidance on the application of preservation and rehabilita- identified feasible treatments. The constraints center on fund- tion treatments for PCC-surfaced pavements. Table 3.13 ing limitations for the preservation work and various other (p. 56) presents examples of both general trigger and limit factors that can affect the constructability of the identified values for different distress and performance indicators and feasible treatments. different traffic volume categories. The trigger values define Detailed discussions of these two feasibility aspects are pro- the point when preservation may be appropriate, while the vided in the sections that follow. Included in these discussions (text continues on page 46)

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Table 3.5. Guidelines for Effective Maintenance Treatments (Based on SHRP Southern Region Review of SPS-3 Test Sites) Treatmentsa Thin Slurry Crack Rout and Rout and Chip Seal: Chip Seal: Pavement Conditions Parameters Overlay Seal Seal Sealb Fillb Finec Coarsec Microsurface Fog Traffic ADT/laned <1000 E E E E E E E E E 1000 < ADT < 4000 E E E E E E-Q E-Q E E-Q >4000 E E E E E E-N-Q E-N-Q E E-Q Rutse <3/8 in. E E E E E E E E E 3 /8 in. < R < 1 in. E M-N E E E M-N-Q M-N-Q E T >1 in. E T E E E T T M-C T Cracking Fatigue Low E E E E E E E E M Moderate E M M M M E E M T High M T T T T E E T T Longitudinal Low E E E E E E E E M Moderate E M E E E E E M T High M T M E E M M T T Transverse Low E E E E E E E E M Moderate E M E E E E E M T High M T M E E M M T T Asphalt Surface Dry E E T T T E E E E surface appearance Flushing E E T T T M-Q E-Q E T condition Bleeding E E T T T N-Q N-Q E T Variable E E T T T M-Q E-Q E Mf Raveling Low E E T T T E E E E Moderate E E T T T E E E M High E M T T T E-Q E-Q E M Potholes Low E E T T T E E E T Moderate E M M T T E E M T High M M M T T M M M T Existing pavement texture is rough E E T T T M-Q M-Q E T Poor ride E E T T T T T M T Rural (minimum turning movements) E T T T T E E E E Urban (maximum turning movements) E E E E E E-Q E-Q E E Subsurface moisture High snowplow usage E E E E E E-Q E-Q E E Low frictional resistance E E T T T E E E T Source: Hicks et al. 2000. Note: E = Effective; M = Marginally effective; N = Not recommended; Q = Requires a higher degree of expertise and quality control; T = Not effective. a The chart provides general guidance only. Engineering judgment and experience should be used to select the proper treatment. b Typically requires routine retreatment at 2-year intervals. c For ADT in excess of 50,000 (total) and/or truck volumes in excess of 20%, this treatment can be effective but is not recommended. d Higher percentages of trucks have a significant effect on performance. e 43 Rutting has occurred over an extended period of time. f Spot treatments on dry conditions only.

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44 45 Table 3.6. FHWA/FP2 Guidelines for Pavement Treatment Selection Treatments Ultra- Full-Depth Thin Reclamation Reflective Std. Mod. High- Bonded Recycled Cold Hot Granular Crack Pavement Fog Crack Sand Chip Chip Performance Slurry Wearing Asphalt In-Place In-Place Thin Base Relief Conditions Parameters Seal Seal Seal Seal Seal Chip Seal Seal Microsurfacing Course Pavement Recycling Recycling Overlay Stabilization Interlayer Traffic (ADT) <1000 * * * * * * * * * * * * * * * (% trucks should 10004000 * * * * * * * * * ? * * * * * also be considered) >4000 ? * X * * * * * * ? * ? * * * Ruts <3/8 in. * * * * * * * * * * * * * * * 3 /81 in. X ? ? ? ? ? ? * X * ? ? ? * ? >1 in. X X X X X X X ? X ? ? X X * ? Cracking fatigue Low ? * * * * * X * * * * * * * * Moderate X ? ? * ? * X ? ? ? * * * * * High X X X X X X X X X ? * ? ? ? * Cracking Low ? * * * * * * * * * * * * * * longitudinal Moderate X * ? * * * ? ? ? ? * * * * * High X ? X X X X X X X X * ? ? * * Cracking transverse Low ? * * * * * * * * * * * * * * Moderate X * ? * ? * ? ? ? ? * * * * * High X ? X X X X X X X X * ? ? * * Surface condition Dry * X * * * * ? * * * * * * * * Flushing X X ? * * * X * * * * * * * ? Bleeding X X X ? * * * * * * * * * * ? Variable ? X ? * * * * * * * * * * * ? PCC X ? * * * * * * * ? X X * X * Raveling Low * X * * * * * * * * * * * * * Moderate ? X * * * * * * * * * * * * * High ? X * * * * ? * * * * * * * * Potholes Low X * * * * * * * * * * * * * * Moderate X ? ? ? ? ? ? ? X * * * * * * High X ? X X X X ? ? X ? * ? * * * Stripping Moist. Damage X X X X X X X X X X ? X X ? X Texture Rough X X ? ? ? ? * * * * * * * * * Ride Poor X X X X X X * ? * * * * * * * Rural Min. turning * * * * * * X * * * * * * * * Urban Max. turning * * ? * * * * * * * * * * * * Drainage Poor X X X X X X X X X X ? X X X ? Snowplow use High * * * ? * * * * * * * * * * * Skid resistance Low X X * * * * * * * * * * * ? * Noise Low ? ? X X X * ? ? * ? ? ? ? ? ? Initial cost concern Low * * * * * * * * * * * * * * * High * ? * * ? * ? X X * ? * ? ? ? Life cost concern Low * * * * ? * * * ? * * * ? * ? High ? * ? ? * * ? * * * * * ? * * Local const. quality Low X ? X X ? * X * * ? X * ? X ? High * * * * * * * * * * * * * * * User-delay $ High ? ? ? ? ? * ? * * ? ? * ? ? * 2 Source: FHWA and FP 2005. Notes: These are broad assumptions. Assessment of a given road should take precedence, with special attention to distress course(s) and needed repairs before treatment. Recommendations in top chart assume good-quality design and construction. Multipliers from the bottom chart should be used. This information is meant to be fed into a decision matrix. X = Not recommended; ? = May be recommended; * = Recommended.

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46 Table 3.7. Guidelines for Preliminary Selection of Candidate Rehabilitation Techniques for HMA-Surfaced Pavements Candidate Rehabilitation Treatments Pavement Distress Cold HIR Surface HIR HIR Thin Thick Combination Mode Mill Recycle Remixing Repaving CIR HMA HMA Treatments Raveling Potholes Bleeding Skid resistance Shoulder drop-off Rutting Corrugations Shoving Fatigue cracking Edge cracking Slippage cracking Block cracking Longitudinal cracking Transverse cracking Reflection cracking Discontinuity cracking Swells Bumps Sags Depressions Ride quality Strength Source: Modified from Dunn and Cross 2001. Courtesy of Asphalt Recycling and Reclaiming Association. Most appropriate Least appropriate (continued from page 42) is information on the best and current practices that are used by an overall condition indicator (PCI/PCR), a serviceability in developing the guidelines featured in Guidelines for the indicator (PSI/PSR), a roughness parameter (IRI), or a variety Preservation of High-Traffic-Volume Roadways. of individual distress indicators (rutting, fatigue cracking, and so on). It is also used to refer to the service life of a pavement, as defined by the time until the pavement needs a major or Performance Needs structural rehabilitation (which can be determined in a variety of ways using time-series condition data or historical pavement Performance Definition construction and rehabilitation event data). The term "performance" takes on many connotations when The meaning of "performance" is further complicated when used in reference to pavements. It normally refers to the applied to a preservation treatment. This is because both the deterioration of pavement condition over time, as gauged performance of the treatment itself and the influence of the

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47 treatment on the performance of the existing pavement are of project literature. The results are summarized in the following interest. In addition, the term "effectiveness" is often used sections. when referring to the immediate, short-term, or long-term effects of the treatment application (Kuennen 2006c). IMPACT OF PAVEMENT CONDITION ON TREATMENT PERFORMANCE For the purposes of this study, performance has been defined Pavement survival analysis of the performance of SPS-3 PM as the length of time that a treatment serves the purpose for treatments in the southern long-term pavement performance which it was placed (i.e., provides a benefit). It is the exten- (LTPP) region revealed quantifiable effects of existing pave- sion in service life imparted to the existing pavement by the ment condition on treatment performance (Eltahan et al. 1999). preservation treatment. This designation of performance is Using a failure criterion defined by severities and quantities most compatible with the procedures needed to evaluate the of cracking, patching, and bleeding, the median survival time cost-effectiveness of preservation treatments as part of a (time until 50% of sections reach failure) of thin HMA over- project-level treatment selection process. lay, slurry seal, chip seal, and crack seal treatments at 28 SPS-3 sites were computed. The results are summarized in Table 3.21 (p. 67). Performance Targets and Requirements A recent study of Ohio DOT PM treatments examined the In addressing treatment feasibility, the user should identify effect of existing pavement condition on treatment performance targeted or required levels of performance for the planned (Rao et al. 2008). Using historical data on hundreds of pave- ment sections on different facility types throughout the state, preservation activity. This performance goal may be based on the study showed that there is generally an increase in the exten- a nominal assessment of (a) the expected performance capa- sion in life of 1 to 2 years corresponding to treatments placed bilities of the alternative treatments for the conditions at hand, on pavements in good condition (PCR between 80 and 90) ver- (b) the long-term planning and programming impacts for the sus those placed on pavements in fair condition (PCR between subject project, and (c) the importance of minimizing delays 70 and 80). This effect is illustrated in Table 3.22 (p. 67). associated with future maintenance and rehabilitation (M&R) The evaluation of preservation treatment performance data activities. by Caltrans indicated significant reductions in performance corresponding to lower overall pavement conditions at the time Expected Treatment Performance of treatment application. Table 3.23 (p. 67) shows the estimated lives of five different treatments when applied at three differ- As a starting point for establishing expected treatment perfor- ent pavement condition levels. As can be seen, there are sig- mance, the project literature was reexamined for information nificant increases in treatment performance (4 to 5 years) for on general treatment performance (and not specifically on high- chip seals, slurry seals, microsurfacing, and thin HMA over- traffic-volume roadways). Although the type of performance lays when they are placed on pavements in good condition data sought was pavement life extension, the availability of rather than on those in fair condition. such data was limited. Hence, treatment life data were also sought and compiled. IMPACT OF TRAFFIC ON TREATMENT PERFORMANCE A collective summary of the performance information for Satisfactory treatment performance in part depends upon the treatments applied to HMA- and PCC-surfaced pavements is ability of the treatment to withstand the stresses placed upon presented in Tables 3.19 and 3.20 (p. 66), respectively. These it by traffic. These stresses include not only the vertical shear ranges are based on information reported by various sources, stresses and abrasive forces of repeated traffic applications representing a variety of conditions and using different per- but also the horizontal shear stresses of turning or braking formance measures. As such, these reported ranges may be vehicles and, in certain environments, the abrasive forces of based as much (or more) on perception instead of on well- studded tires and snowplows. designed, quantitative experimental analyses. There is little published information on a quantitative The literature review discussion in Chapter 2 demonstrated assessment of the impact of traffic level on preservation treat- that preservation treatment performance is affected by the ment performance. Although the LTPP SPS-3 and SPS-4 conditions in which the treatment is installed and must studies included sections of varying traffic levels, the various function. Specifically, treatment effectiveness is influenced published reports covering treatment performance provided by the condition of the pavement upon which it is placed, and no indication of the effect of traffic level on performance. treatment durability is influenced by the level of traffic and A 1998 national study of the longevity and performance of the type of climate to which it is exposed. diamond-ground PCC pavements (Rao et al. 1999) illustrated An investigation of how these factors--pavement condition, the general effect of traffic on surface texture wear following traffic, and climate--affect the general performance ranges grinding, but age and climate were established as the key vari- listed in the previous tables was made by reexamining the ables in a texture deterioration model (traffic and snowplow (text continues on page 57)

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48 49 Table 3.8. Caltrans Flexible Pavement Maintenance Treatment Matrix Treatment Costs Traffic Volume Cost: $/sq yd (Treatment Only) ADT > 5,000 < 30,000 High Snowplow Use Additional Premium Additional Premium Cost per Lane-Mile (total project cost Medium Projects Periods or Work Rutting Climate for Night Work, Zones, $/sq yd. includes traffic Large Projects Small Projects for Short Work ADT > 30,000 ADT < 5,000 Stop Points Mountains Oxidation Bleeding Raveling control) Coastal $/sq yd Desert Urban Valley <1/2 in. >1/2 in. Night Rural Cold Preventive Treatments Crack/joint seal Emulsion N N N N N G G G G G G G N N G G G G 8,000 0.500.65 0.600.75 0.700.85 +0.150.20 +0.601.00 Modified (rubber) N N N N N G G G G G G G G G G G G G 8,000 0.550.70 0.650.80 0.750.90 +0.150.20 +0.601.00 Seal coats Fog seal (see note a) F G N N N G G G G F F N N P F G G F 13,000 0.150.30 0.150.30 0.150.30 +0.05 +0.10 Rejuvenator (see note a) G G N N N G G G G G F N N N N G G F 15,000 0.200.50 0.200.50 0.200.50 +0.10 +0.20 Scrub seal (see note d) G G N N N G G G G G F N N G N F G P 17,000 2.15 2.15 2.15 NA NA Slurry seals Type II (See note a) F G N N N G G G F G G G N N G G G P 23,000 1.602.20 1.752.40 1.902.60 NA +0.30 Type III G G N F N G G G F G G G N N G G G P 24,000 1.602.20 1.752.40 1.902.60 NA +0.30 REAS G G N F N G G G F G G G N N G G G P 1.201.80 1.201.80 1.201.80 NA +0.30 Microsurfacing Type II G G N G F G G G G G G G G N G G G P 31,000 2.002.80 2.102.90 2.253.00 +0.100.20 NA Type III G G N G G G G G G G G G G N G G G P 31,000 2.002.80 2.102.90 2.253.00 +0.100.20 NA Chip seals PME: Med. fine G G N F N G G F F G G N N N P P G P 27,000 1.802.00 2.252.75 3.003.50 NA +0.501.00 (see note d ) PME: Medium G G N F N G G F F G N N N N P P G F 27,000 1.802.00 2.252.75 3.003.50 NA +0.501.00 (see note d ) PMA: Medium G G N F N G G G G G G N N G P P G F 24,000 NA (see note c) PMA: Coarse (see note c) G G N F N G G G G G N N N G P P G G 24,000 NA AR: Medium G G N F N G G G G G G N G G P P G F 65,000 3.754.55 4.004.75 4.255.00 NA +0.501.00 AR: Coarse G G N F N G G G G G N N G G P P G G 65,000 3.754.55 4.004.75 4.255.00 NA +0.501.00 Cape seals Slurry G G N F N G G G G G G G N N G G G P Micro G G N G F G G G G G G G N N G G G P PM alternative to a seal coat >30,000 ADT PBA-O G G P F N G G G G G G G F F G G G P 65,000 812 814 1016 +1.204.00 RAC-O G G P F N G G G G G G G F P G G G P 60,000 1014 1014 +1.503.50 RAC-O high binder (HB) G G P F N G G G G G G G F P G G G P 65,000 1014 1014 +1.503.50 RAC-G G G P G F G G G G G G G F F G G G G 65,000 1014 1014 +1.503.50 PBA-G G G P P N G G G G G G G F F G G G G 60,000 812 814 1016 +1.204.00 Thin bonded wearing G G P F N G G G G G G G F F G G G G 85,000 1014 1014 +1.503.50 course (BWC) Thin bonded wearing G G P F N G G G G G G G F F G G G G 85,000 1014 1014 +1.503.50 course rubber (BWC-RAC-O/G) Maintenance treatments Thin lift overlays Conventional G G P G G G G G G G G G G G G G G G 45,000 812 814 1016 +1.204.00 PBA G G P G G G G G G G G G G G G G G G 60,000 812 814 1016 +1.204.00 RAC G G P G F G G G G G G G F F G G G G 65,000 1014 1014 +1.503.50 Digouts P P G N G G G G G G G G G G G G G G 125,000 Source: Caltrans 2008a. Note: G = Good performance; F = Fair performance; P = Poor performance; N = Not recommended. a Usually limited to shoulders, low-volume roads, and parking areas. b Generally used on shoulders, parking areas, and locations where less-aggressive surface is desired. c Under evaluation. Please consider other strategy at this time. d Use of pass rejuvenating seal under evaluation. Please consider other PME strategy at this time.

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50 51 Table 3.9. Caltrans Treatment Guidelines for Effective Maintenance of Cracking in Bituminous Pavements Type of Cracking Alligator A Alligator B Alligator C Longitudinal/Transverse Edge Criteria Low Medium High Low Medium High Low Medium High Low Medium High Low Medium High Width 1/4, 1/2 1/4, 1/2 1/4, 1/2 1/4, 1/2 No >0%, 10% Material Material Material or or or or or or or or or Loss Loss Loss Area 10%, 20%, 10%, 20%, 10%, 20%, <30% Preventive treatments Crack/joint seal (see note e) Emulsion N F N N P N N N N G F N G P P Modified (rubber) N G P N P N N P N P G F P P P Seal coats Fog seal (see note a) G P N G N N F N N F N N F P P Rejuvenator (see note a) G N N G N N F N N F N N F P P Scrub seals G F N G F (see note d) N G F (see note d) N P N N F P P Slurry seals Type II (see note a) F N N F N N F N N F N N F P P Type III F P N F P N F P N F P N F P P Microsurfacing Type II (see note b) G N N F P N F P N F N N P P P Type III G P N F P N F P N F N N P P P Chip seal PME: Med. fine G P N G F (see note d) N G P (see note d ) N P P N P P P PME: Medium G P N G F (see note d) N G P (see note d ) N P P N P P P PMA: Medium (see note c) G P P G F (see note d) P G P (see note d ) P P P N P P P PMA: Coarse (see note c) G P P G F (see note d) P G P (see note d ) P P P N P P P AR: Medium G G F G G F G F (see note d ) F P F F P P P AR: Coarse G G F G G F G F (see note d ) F P F F P P P PM alternative >30,000 ADT Conventional PBA OGAC G F N G F (see note d) N G F (see note d ) N G F P P P P RAC-O G G F G G F (see note d ) G G F G F P P P P RAC-O high binder (HB) G G F G G F (see note d ) G G F G F P F F F RAC-G G G G G G F (see note d ) G G G G F P G G G Thin bonded wearing course rubber (BWCR) G G G G F (see note d) F (see note d ) G F (see note d ) F F F P P P P Maintenance treatments Conventional G G F G G (see note d) P (see note d ) G G F P F F N F F PBA G G G G G (see note d) P (see note d ) G G G P F F N F F RAC G G P G P (see note d) P G F P P P F N F F BWC G G G G F (see note d) F (see note d ) G F (see note d ) F F F P P P P Digouts N N F N N G N N G N F F N F G Source: Caltrans 2008a. Note: G = Good performance; F = Fair performance: P = Poor performance: N = Not recommended. a Usually limited to shoulders, low-volume roads, and parking areas. b Generally used on shoulders, parking areas, and locations where less-aggressive surface is desired. c Under evaluation. Please consider other strategy at this time. d Effective when proper prep work has been performed. e Per maintenance manual: For cracks <1 4 in., crack seal not recommended. /

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52 Table 3.10. Illinois DOT Flexible Pavement PM Treatment Matrix Crack Crack Fog Sand Scrub Slurry Pavement Conditions Severity Levels Filling Sealing Seal Seal Seal Rejuvenator Seal Microsurfacing Alligator/fatigue crackinga L1 F F NR NR NR NR F F L2, L3, L4 NR NR NR NR NR NR NR NR Block cracking M1 R R F R R F R R M2 R R NR NR F NR F NR M3, M4 F F NR NR NR NR NR NR "Stable" ruttingb N1, N2 NR NR NR NR NR NR F R N3 NR NR NR NR NR NR NR F Joint reflection and transverse O1 NR NR F R R NR F R crackingc O2, O3 R R NR NR NR NR NR F O4, O5 F F NR NR NR NR NR NR Overlayed patch reflective P1, P2, P3, P4, P5 F* F* F* F* F* F* F* F* cracking Longitudinal/center of lane Q1 R R F F F NR F F cracking Q2, Q3 R F NR NR F NR NR F Q4, Q5 NR NR NR NR NR NR NR NR Reflective widening crack R1 R R F F F NR F F R2, R3 F F NR NR NR NR F F R4, R5 NR NR NR NR NR NR NR NR Centerline deterioration S1, S2, S3, S4 F* F* F* F* F* F* F* F* Edge cracking T1 F F F R R NR F F T2 F F NR NR NR NR NR F T3, T4 NR NR NR NR NR NR NR NR Permanent patch deterioration U1, U2, U3, U4 F* F* F* F* F* F* F* F* Shoving, bumps, sags, and V1 NR NR NR NR NR NR NR F corrugation V2, V3 NR NR NR NR NR NR NR NR Weathering/raveling W1, W2 NR NR F F F F R R W3, W4 NR NR NR NR NR NR F F Reflective D-cracking X1, X2, X3 NR NR NR NR NR NR NR NR Friction Poor NR NR NR R R NR R R ADT <5,000 R R R R R R R R 5,00010,000 R R F F F R F R >10,000 R R NR NR NR NR NR F Relative cost ($ to $$$$) $ $ $ $$ $$ $$ $$ $$ Source: IDOT 2009. Notes: ADT = Average daily traffic. CIR = Cold in-place recycling. HIR = Hot in-place recycling. HMA = Hot-mix asphalt. UTW = Ultra-thin whitetopping. R: Recommended treatment for the specified pavement condition. Care must be taken in making sure that all critical distress types are addressed by the selected treatment. R*: Recommended treatment when used with milling prior to treatment. R**: Used in combination with crack sealing. F: Feasible treatment, but depends on other project constraints, including other existing distresses. F*: This is a localized distress and should be treated locally, while other distress types present should dictate choice of global treatment. NR: Treatment is not recommended to correct the specified pavement condition. a Preservation treatments do not correct alligator cracking. Of the treatments, chip seals are most appropriate at addressing alligator cracking. b If stable rutting is present without other distresses, microsurfacing or mill and overlay is the recommended treatment. c If cracking is joint reflection related, the preservation treatments will not correct the distress. (continued on next page)

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53 Table 3.10 (continued) Ultra-Thin Thin Bonded Chip Cape HMA Wearing Cold Drainage Pavement Conditions Seal Seal CIR HIR Overlay Course UTW Mill Preservation Alligator/fatigue crackinga F F F F F F F NR R NR NR NR NR NR NR NR NR F Block cracking R R R R F F R F NR F F F F NR NR NR NR NR NR NR F F NR NR NR NR NR "Stable" ruttingb F F R R R* F R* F R NR NR R R R* NR R* F F Joint reflection and transverse R R F F R** F NR F NR crackingc F F F F F NR NR NR NR NR NR NR NR NR NR NR NR NR Overlayed patch reflective F* F* F* F* F* F* F* F* F* cracking Longitudinal/center of lane F F F F F F F F NR cracking F F F F F F F F NR NR NR F F NR NR NR NR NR Reflective widening crack F F F F F F F F NR F F F F F NR F NR NR NR NR NR NR NR NR NR NR NR Centerline deterioration F* F* F* F* F* F* F* F* F* Edge cracking R F R R R** F F F R F F F F F NR F NR R NR NR NR NR NR NR NR NR F Permanent patch deterioration F* F* F* F* F* F* F* F* F* Shoving, bumps, sags, and F F R R R F F R F corrugation NR NR R R R NR F R F Weathering/raveling R R F F F F F F NR F F R R R* NR NR NR NR Reflective D-cracking NR NR F F NR F NR F NR Friction R R F F R R F F NR ADT R R R R R R R R R R R F R R R R R R F F NR R R R R R R Relative cost $$ $$ $$$ $$$ $$$ $$$ $$$$ $ Varies

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54 Table 3.11. Ohio DOT's GQL Logic Summary for Selecting Candidate PM Projects on Flexible Pavements Crack Single Double PMAC Thin HMAC Sealing Chip Seal Microsurfacing Microsurfacing Overlay Overlay Raveling L: OFE L: OFE L: OFE L: OFE L: OFE L: NA M: O M: M: M: OFE M: OFE M: NA H: H: H: H: H: H: NA Bleeding L: L: L: L: L: L: NA M: M: M: O M: OFE M: O M: NA H: H: H: H: H: H: NA Patching L: O L: L: L: L: O L: O M: O M: M: M: M: O M: O H: O H: H: H: H: O H: O Debonding L: O L: L: L: L: O L: O M: M: M: M: M: O M: O H: H: H: H: H: O H: O Crack seal deficiency L: E L: NA L: NA L: NA L: NA L: NA M: E M: NA M: NA M: NA M: NA M: NA H: E H: NA H: NA H: NA H: NA H: NA Rutting L: OFE L: OFE L: OFE L: OFE L: OFE L: OFE M: O M: M: M: O M: M: O H: H: H: H: H: H: Settlement L: NA L: NA L: NA L: NA L: NA L: NA M: NA M: NA M: NA M: NA M: NA M: NA H: NA H: NA H: NA H: NA H: NA H: NA Potholes L: NA L: L: L: L: O L: O M: NA M: M: M: M: O M: O H: NA H: H: H: H: O H: O Wheel track cracking L: OFE L: OFE L: OF L: OF L: OF L: OF M: O M: M: O M: O M: O M: O H: H: H: H: H: H: Block and transverse cracking L: OFE L: OF L: OFE L: OFE L: OFE L: OFE M: O M: O M: O M: OF M: OF M: OF H: H: H: H: H: H: Longitudinal cracking L: OFE L: OFE L: OFE L: OFE L: OFE L: OFE M: O M: OFE M: OFE M: OFE M: OFE M: OFE H: H: H: H: H: H: Edge cracking L: OFE L: OF L: OF L: OFE L: OF L: OF M: O M: O M: O M: O M: O M: O H: H: O H: O H: O H: O H: O Thermal cracking L: OFE L: OFE L: OFE L: OFE L: OFE L: OFE M: O M: O M: O M: O M: OF M: OF H: H: H: H: H: H: Sources: Rao et al. 2008; ODOT 2001. Notes: PMAC = Polymer-modified asphalt concrete. L, M, H: Low, medium, and high severity, respectively. O, F, E: Occasional, frequent, and extensive, respectively. = Not suitable for distress severity level. NA = Particular distress is not considered in the logical decision.

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55 Table 3.12. Ohio DOT's GQL Logic Summary for Selecting Candidate PM Projects on Composite Pavements Crack Single Double PMAC Thin HMAC Sealing Chip Seal Microsurfacing Microsurfacing Overlay Overlay Raveling L: OFE L: OFE L: OFE L: OFE L: OFE L: NA M: O M: M: M: OFE M: OFE M: NA H: H: H: H: H: H: NA Bleeding L: L: L: L: L: L: NA M: M: M: O M: OFE M: O M: NA H: H: H: H: H: H: NA Patching L: O L: L: L: L: O L: O M: O M: M: M: M: O M: O H: O H: H: H: H: O H: O Disintegration/debonding L: O L: L: L: L: O L: O M: M: M: M: M: O M: O H: H: H: H: H: O H: O Rutting L: OFE L: OFE L: OFE L: OFE L: OFE L: OFE M: O M: M: M: O M: M: O H: H: H: H: H: H: Pumping L: O L: L: L: L: L: M: O M: M: M: M: M: H: H: H: H: H: H: Shattered slab L: NA L: L: L: L: L: M: NA M: M: M: M: M: H: NA H: H: H: H: H: Settlement L: NA L: NA L: NA L: NA L: NA L: NA M: NA M: NA M: NA M: NA M: NA M: NA H: NA H: NA H: NA H: NA H: NA H: NA Transverse cracks L: OFE L: OFE L: OFE L: OFE L: OFE L: OFE M: OFE M: M: M: O M: OF M: OF H: H: H: H: H: H: Joint reflection cracking L: OFE L: OFE L: OFE L: OFE L: OFE L: OFE M: OFE M: M: M: O M: OF M: OF H: H: H: H: H: H: Intermediate transverse cracking L: OFE L: O L: O L: O L: O L: O M: OFE M: M: M: M: O M: O H: H: H: H: H: H: Longitudinal cracking L: OFE L: OFE L: OFE L: OFE L: OFE L: OFE M: O M: O M: O M: OFE M: OFE M: OFE H: H: H: H: H: H: Pressure damage/upheaval L: NA L: O L: O L: O L: O L: O M: NA M: M: M: M: M: H: NA H: H: H: H: H: Crack seal deficiency L: FE L: NA L: NA L: NA L: NA L: NA M: FE M: NA M: NA M: NA M: NA M: NA H: FE H: NA H: NA H: NA H: NA H: NA Corner breaks L: NA L: O L: O L: O L: O L: O M: NA M: M: M: M: M: H: NA H: H: H: H: H: Punchouts L: L: L: L: L: L: M: M: M: M: M: M: H: H: H: H: H: H: Sources: Rao et al. 2008; ODOT 2001. Notes: PMAC = Polymer-modified asphalt concrete. L, M, H: Low, medium, and high severity, respectively. O, F, E: Occasional, frequent, and extensive, respectively. = Not suitable for distress severity level. NA = Particular distress is not considered in the logical decision.

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60 Table 3.15. Highway Agency Treatment Usage on HMA-Surfaced Roadways According to Pavement Condition Pavement Distress Surface Distressa Treatment Raveling Oxidation Bleeding Smoothness Friction Noise Light Moderate Heavy Crack filling NA NA NA Limited NA Limited Extensive Moderate Limited Crack sealing NA NA NA Limited NA Limited Extensive Moderate Limited Slurry seal Extensive Extensive Limited Limited Limited None Moderate Limited None Microsurfacing Moderate Moderate Limited Moderate Moderate Limited Extensive Moderate Limited Chip seals Moderate Extensive Limited Limited Moderate None Extensive Extensive Limited Ultra-thin bonded wearing course Moderate Moderate Limited Moderate Extensive Limited Extensive Moderate Limited Thin HMA overlay Extensive Moderate Moderate Extensive Moderate Limited Extensive Extensive Limited Cold milling and overlay Extensive Moderate Moderate Extensive Moderate Limited Extensive Extensive Moderate Ultra-thin HMA overlay Moderate Moderate Moderate Moderate Moderate Limited Extensive Moderate Limited Hot in-place HMA recycling Moderate Moderate Limited Moderate Moderate Limited Extensive Moderate Moderate Cold in-place recycling Limited Limited Limited Moderate Limited Limited Moderate Extensive Extensive Profile milling None None Limited Extensive Moderate Limited Moderate Limited None Ultra-thin whitetopping Limited Limited Limited Moderate Limited Limited Moderate Moderate Limited Note: Extensive = Used by 66% of respondents; Moderate = 33% to 66% usage; Limited = <33% usage. a Various forms of cracking.

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61 Table 3.16. Highway Agency Treatment Usage on PCC-Surfaced Roadways According to Pavement Condition Pavement Distress Surface Distressa Treatment Smoothness Friction Noise Light Moderate Heavy Concrete joint resealing Limited None Limited Extensive Moderate Limited Concrete crack sealing Limited None Limited Extensive Moderate Limited Diamond grinding Extensive Moderate Moderate Limited Limited Limited Diamond grooving Moderate Extensive Limited Limited Limited Limited Partial-depth concrete patching Moderate None Limited Moderate Extensive Moderate Full-depth concrete patching Moderate Limited Limited Limited Extensive Extensive Dowel bar retrofit Moderate Limited Limited Limited Moderate Moderate Ultra-thin bonded wearing course Extensive Moderate Limited Moderate Moderate Limited Thin HMA overlay Moderate Moderate Limited Moderate Moderate Limited Note: Extensive = Used by 66% of respondents; Moderate = 33% to 66% usage; Limited = <33% usage. a Spalling, various forms of cracking. (continued from page 57) (8.5 years) of the expected performance range (5 to 12 years) due to agency or contractor inexperience or limitations in of the thin overlay treatment. This resulted in a reduction the quality of locally available materials. One approach to of 30%. The lower and upper limits of each treatment's account for construction quality risk is to apply a confidence general expected performance range were then reduced by factor to the expected performance range, with a factor of this percentage. The adjusted ranges are listed in Tables 3.26 1.0 representing 100% confidence, 0.75 representing 75% (p. 69) and 3.27 (p. 70) and were incorporated into the preser- confidence, and so on. Thus, if the expected performance vation guidelines document. of a treatment ranged from 4.0 to 6.0 years and the level of To ensure that the effects of existing pavement condition confidence was 75% (reflecting some shortcomings in agency and climate are properly accounted for, the preservation guide- or contractor experience or materials quality), then the range lines suggest using values near the lower limit of the perfor- would be reduced to between 3.0 and 4.5 years. mance range for treatments to be applied on pavements in fair condition and located in severe-freeze environments. On Construction Constraints the other hand, it is suggested that values near the upper limit of the range be used for treatments applied to pavements in There are several construction factors that affect the feasibility of a preservation treatment, including the following: good condition and located in nonfreeze environments. For the purposes of this study, three climatic regions were The anticipated or targeted time frame (i.e., time of year) for identified based on the LTPP test site classifications established construction. Each candidate treatment must be examined in by Jackson and Puccinelli (2006). These regions consist of the terms of the weather patterns (temperature, precipitation) following: for which they are most suitable for application and of the various weather-related effects (e.g., moisture left in Deep freeze (northern-tier states, freezing index [FI] > 400); pavement structure, salt or sand from winter maintenance Moderate freeze (middle-tier states, 50 < FI 400); and operations remaining in cracks and joints). Table 3.28 Nonfreeze (southern-tier states and portions of coastline, (p. 71) provides an illustration of one agency's recommen- FI 50). dations for treatment timing restrictions. Work zone duration restrictions. Depending on agency An approximate delineation of the climate zone boundaries policies and practices and a variety of other factors (traffic is presented in Figure 3.10 (p. 70). volume and speed, driving difficulty, facility setting, and One final consideration in assessing treatment performance so on), there may be a need to restrict the duration of work is the potential for substandard construction and performance zone setups so as to minimize congestion and maximize (text continues on page 69)

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62 Table 3.17. Guideline Decision-Support Matrix for Preliminary Identification of Candidate Treatments for HMA-Surfaced Pavements Distress Types and Severity Levels (L Low, M Medium, H High) Surface Distress Cracking Distress Window of Water Fatigue/ Opportunity Ravel/ Bleed/ Segre- Bleed/ Long WP/ Trans Joint Long/ Weather Flush Polish gation Pumpa Slippage Block Therm Reflect Edge Preservation PCI/ Age Treatment PCR (yr) L/M/H -- -- L/M/H -- L/M/H L/M/H L/M/H L/M/H L/M/H Crack fill 7590 36d Crack seal 8095 25 d Slurry seal (Type III) 7085 58 Microsurfacing: Single 7085 58 Microsurfacing: Double 7085 58 Chip seal: Single Conventional 7085 58 Polymer modified 7085 58 Chip seal: Double Conventional 7085 58 Polymer modified 7085 58 Ultra-thin bonded 6585 510 wearing course Ultra-thin HMAOL 6585 510 Thin HMAOL 6080 612 Cold milling and 6075 712 thin HMAOL Hot in-place recycling Surf recycle/HMAOL 7085 58 Remixing/HMAOL 6075 712 Repaving 6075 712 Cold in-place recycling 6075 712 and HMAOL Profile milling 8090 36 Ultra-thin whitetopping 6080 612 Note: = Highly Recommended; = Generally Recommended; = Provisionally Recommended; = Not Recommended. a Porous surface mix problem. b Rutting primarily confined to HMA surface layer and largely continuous in extent. c Corrugation/shoving primarily HMA surface layer mix problem and frequent in extent. d For composite AC/PCC pavements, a more probable window of opportunity is 24 years for crack filling and 13 years for crack sealing. e Localized application in the case of bumps. (continued on next page)

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63 Table 3.17 (continued) Distress Types and Severity Levels Surface Deformation Distress Characteristics Issues Wear/ Stable Corrug/ Bumps/ Ride Ruttingb Shovec Sags Patches Quality Friction Noise Preservation Treatment L/M/H L/M/H L/M/H L/M/H -- -- -- Crack fill Crack seal Slurry seal (Type III) Microsurfacing: Single Microsurfacing: Double Chip seal: Single Conventional Polymer modified Chip seal: Double Conventional Polymer modified Ultra-thin bonded wearing course Ultra-thin HMAOL Thin HMAOL Cold milling and thin HMAOL Hot in-place recycling Surf recycle/HMAOL Remixing/HMAOL Repaving Cold in-place recycling and HMAOL Profile milling e e Ultra-thin whitetopping

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64 Table 3.18. Guideline Decision-Support Matrix for Preliminary Identification of Candidate Treatments for PCC-Surfaced Pavements Distress Types and Severity Levels (L Low, M Medium, H High) Surface Distress Window of Map Opportunity Crack/Scale Water Polish (Non-ASR) D-Crack Popouts Bleed/Pump PCI/ Age Preservation Treatment PCR (yr) -- -- L/M/H -- -- Concrete joint resealing 7590 510 Concrete crack sealing 7090 512 Diamond grinding 7090 512 Diamond grooving 7090 512 Partial-depth concrete patching 6585 615 Full-depth concrete patching 6585 615 b Dowel bar retrofitting 6585 615 Ultra-thin bonded wearing course 7090 512 Thin HMA overlay 7090 512 Note: = Highly Recommended; = Generally Recommended; = Provisionally Recommended; = Not Recommended. a May be appropriate in conjunction with partial- and/or full-depth repairs to ensure smooth profile. b Isolated incidences of D-cracking only. c Isolated incidences of faulting only. d Likely needed in conjunction with diamond grinding. (continued on next page)

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65 Table 3.18 (continued) Distress Types and Severity Levels Surface Characteristics Joint Distress Cracking Distress Deformation Distress Issues Joint Seal Joint Long/ Ride Damage Spall Corner Trans Faulting Patches Quality Friction Noise Preservation Treatment L/M/H L/M/H L/M/H L/M/H L/M/H L/M/H -- -- -- Concrete joint resealing Concrete crack sealing Diamond grinding a Diamond grooving Partial-depth concrete patching Full-depth concrete patching c Dowel bar retrofitting d Ultra-thin bonded wearing course Thin HMA overlay

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66 Table 3.19. General Expected Performance of Preservation Treatments Applied to HMA-Surfaced Pavements Expected Performance Expected Performance Treatment (Treatment Life) (yr) (Pavement Life Extension) (yr) Crack filling 2 to 4 NA Crack sealing 3 to 8 2 to 5 Slurry seal 3 to 5 4 to 5 Microsurfacing Single course 3 to 6 3 to 5 Double course 4 to 7 4 to 6 Chip seal Single course 3 to 7 5 to 6 Double course 5 to 10 8 to 10 Ultra-thin bonded wearing course 7 to 12 NA Thin HMA overlay Dense graded 5 to 12 NA Open graded (OGFC) 6 to 12 NA Gap graded (SMA) NAa NA Cold milling and thin HMA overlay 5 to 12 NA Ultra-thin HMA overlay 4 to 8 NA Hot in-place recycling Surface recycle and thin HMA overlay 6 to 10b NA Remixing and thin HMA overlay 7 to 15c NA Repaving 6 to 15 NA Cold in-place recycling and thin HMA overlay Between 6 to 8 and 7 to 15d NA Profile milling 2 to 5 NA Ultra-thin whitetopping NA NA Sources: Peshkin et al. 1999; Lamptey et al. 2005; Peshkin and Hoerner 2005; Dunn and Cross 2001; Newcomb 2009; Cuelho et al. 2006; Okpala et al. 1999; Caltrans 2008a; NDOR 2002. Note: NA = Not available. a Current indications are that SMA overlays perform the same or slightly better than dense-graded overlays. b Range based on reported performance of surface recycle and subsequent surface treatment. c Range based on reported performance of remixing and subsequent HMA overlay of unspecified thickness. d Range based on reported performance of CIR and subsequent surface treatment (6 to 8 years) and CIR and subsequent HMA overlay of unspecified thickness (7 to 15 years). Table 3.20. General Expected Performance of Preservation Treatments Applied to PCC-Surfaced Pavements Expected Performance Expected Performance Treatment (Treatment Life) (yr) (Pavement Life Extension) (yr) Concrete joint resealing 2 to 8 5 to 6 Concrete crack sealing 4 to 7 NA Diamond grinding 8 to 15 NA Diamond grooving 10 to 15 NA Partial-depth concrete patching 5 to 15 NA Full-depth concrete patching 5 to 15 NA Dowel bar retrofit 10 to 15 NA Ultra-thin bonded wearing course 6 to 10 NA Thin HMA overlay 6 to 10 NA Sources: Peshkin et al. 1999; Smith et al. 2008; Peshkin et al. 2007; Caltrans 2008a; Caltrans 2008b; NDOR 2002.

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67 Table 3.21. Median Survival Time of PM Treatments Table 3.23. Projected Performance of Preservation Treatments in California Pretreatment Pavement Thin HMA Chip Slurry Crack Good Fair Poor Condition Overlay Seal Seal Seal Condition Condition Condition (PCI 80) (PCI 60) (PCI 40) Good 7.5 yr NA 6.5 yr 6.5 yr Treatment (yr) (yr) (yr) Fair 7.3 yr NA 5.0 yr 7.2 yr Fog seal 3 to 5 1 to 3 1 to 2 Poor 2.2 yr NA 2.5 yr 0.75 yr Chip seal 7 to 10 3 to 5 1 to 3 Source: Eltahan et al. 1999. Slurry seal 7 to 10 3 to 5 1 to 3 Microsurfacing 8 to 12 5 to 7 2 to 4 Thin HMA overlay 10 to 12 5 to 7 2 to 4 Source: Hicks and Marsh 2005. Table 3.22. Performance of PM Treatments in Ohio Pavement Life Extension, Based PCR on Projected Treatment Age Range at Existing Primary Applications (yr) at Terminal PCR of: Time of Pavement with Respect to PM Treatment Treatment Type Highway Classa 80 75 70 65 Chip seals 70 to 80 Flexible General 6.0 9.0 12.0 80 to 90 Flexible General 6.5 9.0 12.0 All All All 6.25 9.0 12.0 Single-course microsurfacing 70 to 80 Flexible General and urban 3.75 5.75 7.5 9.5 80 to 90 Flexible General and urban 5.0 7.0 8.5 10.5 70 to 80 Composite Urban and priority 2.25 4.0 6.25 8.5 80 to 90 Composite Urban and priority All All All 3.75 5.5 7.25 9.25 Double-course microsurfacing 70 to 80 Flexible Priority and urban 3.75 5.25 7.0 9.0 80 to 90 Flexible Priority and urban 70 to 80 Composite Priority and urban 80 to 90 Composite Priority and urban 6.5 8.5 10.5 12.0 All All All 5.0 6.5 8.25 10.0 Ultra-thin bonded wearing courseb 70 to 80 All Priority 6.0 8.0 10.0 11.5 80 to 90 All Priority 6.0 8.0 10.25 12.0 All All All 6.0 8.0 10.0 11.5 PMAC overlaysc 70 to 80 Flexible Priority and urban 6.5 8.25 10.25 12.0 80 to 90 Flexible Priority and urban 7.0 8.25 10.25 12.0 70 to 80 Composite Priority and urban 6.0 8.25 10.75 12.0 80 to 90 Composite Priority and urban All All All 6.5 8.25 10.25 12.0 Thin HMA overlays (without repairs) 70 to 80 Flexible General, urban, and priority 8.5 11.0 14.0 80 to 90 Flexible General, urban, and priority 10.25 12.0 15.0 70 to 80 Composite Priority and urban 7.0 9.25 12.0 80 to 90 Composite Priority and urban 10.0 12.0 15.0 All All All 8.5 11.0 14.0 Thin HMA overlays (with repairs) 70 to 80 Flexible Urban and general 11.0 12.0 15.0 80 to 90 Flexible Urban and general 70 to 80 Composite General, urban, and priority 11.0 12.0 15.0 80 to 90 Composite General, urban, and priority All All All 11.0 12.0 15.0 Source: Rao et al. 2008. Note: PMAC = Polymer-modified asphalt concrete. a ODOT Highway Classification: Priority = Interstates and four-lane NHS highways outside urban area; Urban = Nonpriority state routes in urban areas; General = All remaining state routes (mostly two-lane highways). b Proprietary product NovaChip. c Proprietary product SmoothSeal.

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68 Source: Chou et al. 2008. Figure 3.9. Average performance trends of thin HMA overlay on Ohio priority-system and general-system pavements. Table 3.24. Expected Pavement Service Life Extensions Affected by Pavement Preservation Treatments in Colorado, Corresponding to Truck Traffic Levels Expected Pavement Life Extension (yr) for: Pavement Treatment Type AADTT 6,000 tpd Crack filling Flexible 4 2 2 Crack sealing Flexible 4 3 2 Sand seals Flexible 3 Not advised Not advised Chip seals Flexible 6 to 9 3 to 6 2 to 3 Microsurfacing (single course) Flexible 6 to 9 3 to 5 2 to 3 Microsurfacing (multiple course) Flexible 8 to 9 4 to 6 2 to 4 Ultra-thin bonded wearing course Flexible 9 7 5 Thin HMA overlay Flexible 10 to 11 5 to 9 3 to 5 Mill and thin HMA overlay Flexible 10 to 11 5 to 10 3 to 5 Crack sealing Rigid 6 3 2 Joint resealing Rigid 4 to 6 3 to 5 2 to 3 Diamond grinding Rigid 6 3 2 to 3 Partial-depth spall repair Rigid 4 to 6 2 to 3 3 Dowel bar retrofitting Rigid 4 to 6 2 to 3 3 Full-depth concrete repair Rigid 6 to 11 3 to 10 5 Source: Galehouse 2004. Note: AADTT = average annual daily truck traffic; tpd = trucks per day.

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69 Table 3.25. Estimates of Treatment Performance indicated that most treatments can satisfy the tightest in Four Climatic Zones restriction of a single daytime or overnight shift. For treat- ments applied to HMA-surfaced pavements, only ultra- Thin HMA Chip Slurry Crack thin whitetopping was reported as not being able to meet Climate Zone Overlay Seal Seal Seal this restriction; longer closure time is needed in order for the Dry nonfreeze >12 yr 7 yr >12 yr 910 yr PCC to cure and reach an acceptable strength level. For PCC-surfaced pavements, longer closure times are gener- Dry freeze 67 yr 11 yr 5 yr 6 yr ally required for partial-depth and full-depth repairs and Wet nonfreeze >12 yr >12 yr >12 yr 7 yr for dowel bar retrofitting. Although the use of high early Wet freeze 7 yr 67 yr 5 yr 34 yr strength PCC mixes and fast-track proprietary repair Source: Morian et al. 1998. materials (and precast full-depth repair panels) do enable these treatments to be used in single-shift or overnight closures, the costs are often significantly greater than the (continued from page 61) conventional cementitious materials used and their dura- safety. Such restrictions could be tight, entailing that work bility is more variable. be performed in a single daytime or overnight shift, or more Roadway geometrics. Every project consists of a unique set moderate, allowing work to take place over a weekend, for of geometric conditions or circumstances. The presence of example. features such as significant horizontal or vertical curves, The impact of work zone duration restrictions must intersections or interchanges, overhead bridges or sign be evaluated against the time-to-opening requirements of structures, paved shoulders, and curb-and-gutter could be each candidate treatment. The preservation survey results problematic to the construction of certain preservation Table 3.26. Expected Performance of Preservation Treatments Applied to HMA-Surfaced Pavements on High-Traffic-Volume Roads Expected Performance Expected Performance Treatment (Treatment Life) (yr) (Pavement Life Extension) (yr) Crack filling 1.5 to 3 NA Crack sealing 2.0 to 5.5 2 to 5 Slurry seal 2.0 to 3.5 4 to 5 Microsurfacing Single course 2.0 to 4.0 3 to 5 Double course 3.0 to 5.0 4 to 6 Chip seal Single course 2.0 to 5.0 5 to 6 Double course 3.5 to 7.0 8 to 10 Ultra-thin bonded wearing course 5.0 to 8.5 NA Thin HMA overlay Dense graded 3.5 to 8.5 NA Open graded (OGFC) 4.5 to 8.5 NA Gap graded (SMA) NA NA Cold milling and thin HMA overlay 3.5 to 8.5 NA Ultra-thin HMA overlay 2.5 to 5.5 NA Hot in-place recycling Surface recycle and thin HMA overlay 4.0 to 7.0 NA Remixing and thin HMA overlay 5.0 to 10.5 NA Repaving 4.0 to 10.5 NA Cold in-place recycling and thin HMA overlay 5.0 to 7.5 NA Profile milling 1.5 to 3.5 NA Ultra-thin whitetopping NA NA Note: NA = Not available.

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70 Table 3.27. Expected Performance of Preservation Treatments Applied to PCC-Surfaced Pavements on High-Traffic-Volume Roadways Expected Performance Expected Performance Treatment (Treatment Life) (yr) (Pavement Life Extension) (yr) Concrete joint resealing 1.5 to 5.5 5 to 6 Concrete crack sealing 3.5 to 4.0 NA Diamond grinding 5.5 to 7.0 NA Diamond grooving 7.0+ NA Partial-depth concrete patching 3.5 to 10.5 NA Full-depth concrete patching 3.5 to 10.5 NA Dowel bar retrofitting 7.0 to 10.5 NA Ultra-thin bonded wearing course 4.0 to 6.5 NA Thin HMA overlay 4.0 to 6.5 NA treatments. Likewise, how each candidate treatment would Traffic accommodation and safety issues. Some projects may deal with existing pavement markers and striping must be include geometrics or other features that could be problem- determined. atic from the standpoint of accommodating or controlling Availability of experienced contractors and quality materials. traffic during treatment construction. Each candidate treat- Certain treatments, like microsurfacing, in-place re- ment must be evaluated for shortcomings in these regards. cycling, and diamond grinding, require specialized Environmental considerations. In some agencies and for equipment and materials that may not be locally available. certain locations (generally urban areas), a special emphasis Others may require a level of expertise or high-quality is placed on using construction activities that are sensitive materials that may also not be locally available. Each can- to the environment. Techniques that involve reduced carbon didate treatment must be evaluated for shortcomings in emissions and recycling of materials or that fit well with these regards. pavement sustainability concepts are viewed as desirable. Deep Freeze Moderate Freeze Nonfreeze Source: Adapted from Jackson and Puccinelli 2006. Figure 3.10. Deep freeze, moderate freeze, and nonfreeze climatic regions.