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A P P E N D I X B Examples of Identifying Feasible Preservation Treatments This appendix presents two example exercises intended to preservation is deemed appropriate, the agency's goal is for illustrate how the feasibility matrices in Tables 3.2 through 3.5 the treatment to perform adequately for at least 4 years. The can be used to identify feasible preservation treatments for a agency perceives no constraints regarding the availability of particular project. The first example is for treatment of an locally qualified contractors and good quality materials. And, existing HMA-surfaced pavement, while the second is for finally, traffic conditions are such that lane closure durations treatment of an existing PCC-surfaced pavement. Each exam- longer than 1 day are acceptable. ple includes a description of the project, presentation of the pavement condition and other relevant project information, Preliminary Feasibility Analysis and a discussion of the analyses performed to arrive at a final list of feasible treatments. The existing pavement condition data listed in Table B-1 indi- cate that there is little structural deterioration and that the vast majority of the deficiencies can be treated through preservation Example 1: Rural, techniques. The overall condition levels--PCR in the low- to HMA Roadway mid-80s--are such that preventive maintenance techniques and some minor rehabilitation techniques would be appropri- Project Description ate, even after factoring in the reduction expected to occur The project featured in this example is set in a rural, deep- between 2009 and 2010. freeze environment and involves a four-lane interstate facil- The most prevalent deficiencies are low- and medium- ity. The roadway is 8.4 mi long and has an ADT of 14,000 vpd, severity raveling, medium- and high-severity transverse ther- with 11% trucks. The posted speed limit is 65 mph and access mal cracking, low-severity longitudinal cold-joint cracking, is controlled through three distantly spaced interchanges. The and low- and high-severity stable rutting. Smoothness levels project terrain is flat to mildly rolling, and there are no signif- have gradually decreased, but are still reasonably high. Fric- icant horizontal curves. tion along the project has remained at satisfactory levels. The existing pavement structure was built as a reconstructed Evaluating the condition data in the backdrop of the prelim- pavement in 2001 and was designed for a 20-year period. The inary feasibility matrix given in Table 3.2, it can be seen that the pavement consists of 8.5 in. of HMA (1.5 in. surface course, following treatments are generally or highly recommended for 2.0-in. intermediate course, and 5.0-in. base course) on top of treating the above distresses: 8 in. of dense-graded aggregate base and a lime-stabilized sub- grade. Since construction, the pavement has undergone three Raveling. Slurry seal, single- and double-course micro- condition surveys and two tests each for smoothness and fric- surfacing, single-course conventional chip seal, ultra-thin tion. The results of these surveys/tests, which are based on an bonded wearing course, ultrathin HMA overlay, and thin evaluation of the outside/driving lane, are summarized in HMA overlay. Table B-1. Transverse thermal cracking. Crack sealing, slurry seal, The agency thinking is that either some form of preserva- single- and double-course microsurfacing, single- and dou- tion can be performed in 2010 or that a more significant reha- ble-course conventional chip seal, single- and double- bilitation can be done in the 20132015 time frame. Funding course polymerized chip seal, ultra-thin bonded wearing for a 2010 preservation activity is largely available and, if course, ultrathin HMA overlay, thin HMA overlay, mill 47

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48 Table B.1. Summary of Pavement Condition Data Condition Survey Year Smoothness Testing Year Friction Testing Year Existing Pavement Condition Parameters 2005 2007 2009 2007 2009 2007 2009 PCR Eastbound (EB) 95 90 81 Westbound (WB) 96 92 84 Raveling, LS (% area) EB 3.0 11.2 18.4 WB 1.1 3.5 6.8 Raveling, MS (% area) EB 1.3 4.7 7.3 WB 0.0 0.0 1.5 Segregation, LS (% area) EB 0.0 0.0 0.0 WB 6.5 4.5 3.2 Segregation, MS (% area) EB 0.0 0.0 0.0 WB 0.5 3.2 4.7 Trans-thermal cracking, LS (cracks/mi) EB 60 92 87 WB 45 96 102 Trans-thermal cracking, MS (cracks/mi) EB 6 35 49 WB 11 52 64 Long cold-joint cracking, LS (ft/mi) EB 120 967 2,412 WB 75 624 1,798 Long cold-joint cracking, MS (ft/mi) EB 0 54 367 WB 0 24 165 Stable rutting, LS (0.125 to 0.375 in.) (ft/mi) EB 110 1,256 5,868 WB 45 735 3,987 Stable rutting, MS (0.5 to 1.0 in.) (ft/mi) EB 0 151 1,268 WB 0 54 862 Fatigue cracking, LS (% wheel path area) EB 0.2 1.0 2.2 WB 0.0 0.3 1.5 IRI (Average Std Dev) (in./mi) EB 96.4 9.7 112.5 12.0 WB 88.5 6.2 105.7 10.3 FN40S (Average Std Dev) EB 45.4 3.2 43.6 2.6 WB 47.1 4.5 43.8 4.9

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49 and HMA overlay, HIR remixing and HMA overlay, HIR were performed in 2000, 2004, and 2008. The results of the repaving, and CIR. condition, smoothness, and friction surveys are summarized Longitudinal cold-joint cracking. Crack filling, slurry seal, in Table B-2. In addition to these results, on-board sound single- and double-course microsurfacing, single- and intensity (OBSI) testing performed in 2008 indicated that the double-course conventional chip seal, single- and double- pavementtire noise levels generated by the transversely tined course polymerized chip seal, ultra-thin bonded wearing concrete ranged from 106 to 108 dB(A). course, ultrathin HMA overlay, thin HMA overlay, HIR Agency funding for some form of preservation is available recycling and HMA overlay, HIR remixing and HMA overlay, for the 2010 construction season. The agency's goal for preser- HIR repaving, and CIR. vation treatment performance is 8 years. Traffic conditions are Stable rutting. Double microsurfacing, single- and double- such that lane closure durations longer than a 2-day weekend course conventional chip seal, single- and double-course are unacceptable. Also, there are no perceived availability polymerized chip seal, thin HMA overlay, cold mill and thin constraints regarding locally qualified contractors and good- HMA overlay, HIR surface recycling and HMA overlay, HIR quality materials. remixing and HMA overlay, HIR repaving, and CIR. Treatments appropriate for all four distress types include Preliminary Feasibility Analysis double microsurfacing, single-course conventional chip seal, The existing pavement condition data listed in Table B-2 ultrathin HMA overlay, and thin HMA overlay. indicate that there is no need for major rehabilitation in the near future. Only a few slabs have structural cracks and the Final Feasibility Analysis rate at which these cracks have developed is low. The table also indicates that the deficiencies are mostly functional and Evaluating these four treatments using the feasibility matrix in that the overall condition and smoothness levels are in the Table 3.4, it can be seen that one treatment--ultra-thin HMA proper ranges for preservation, even after factoring in the overlay--probably lacks the durability for a deep-freeze cli- condition changes expected to occur between 2008 and 2010. mate. Also, the expected performance lives of the double The most prevalent deficiencies are transverse and longi- microsurfacing and single-course conventional chip seal in a tudinal joint seal damage, transverse and longitudinal joint deep-freeze climate are probably such that they barely meet the spalling, and polished aggregate. Friction trends have con- agency's performance goal of 4 years. firmed the polishing problem and current friction levels are From the results of this analysis, it is reasonable to proceed either in or are approaching the marginal zone. Agency review with a cost-effectiveness analysis that includes double micro- of wet-weather accident rates has indicated a possible concern surfacing, single-course conventional chip seal, and thin with the friction levels. HMA overlay as the treatment alternatives. If agency experi- Evaluating the condition data in the backdrop of the pre- ence has indicated that the durability of ultra-thin HMA liminary feasibility matrix given in Table 3.3, it can be seen overlays is not significantly affected by the harsh climate, then that the following treatments are generally or highly recom- this treatment could also be evaluated for cost-effectiveness. mended for treating the above distresses: Example 2: Urban, Polishing. Diamond grinding, ultra-thin bonded wearing PCC Roadway course, and thin HMA overlay. Joint seal damage. Joint resealing. Project Description Joint spalling. Partial-depth patching. The project featured in this example is set in an urban, mod- Corner cracking. Crack sealing, full-depth patching. erate-freeze environment and involves a six-lane freeway that Transverse cracking. Crack sealing. is 4.3 mi long. The existing pavement structure is a 9.5-in. Friction. Diamond grinding, diamond grooving, ultra- doweled jointed plain concrete (JPC) pavement (15-ft joint thin bonded wearing course, and thin HMA overlay. spacing) resting on a 4-in. asphalt-treated base (ATB) and a lime-stabilized subgrade. The pavement was built in 1996 Although none of these treatments address all six deficien- with a 25-year design life. Current traffic consists of a 55,000 cies, some combination treatments can be formed that will ADT and 16.8% trucks. The posted speed limit is 55 mph and collectively address them. Possible combinations include the there are four interchanges along the length of the project. following: The terrain is flat and there are no horizontal curves. Automated pavement-condition surveys (including smooth- Diamond grinding, crack sealing, and joint resealing; ness) have been performed on the outside/driving lane every Limited partial- and full-depth patching, diamond grind- third year since construction. Friction tests for this same lane ing, and joint resealing;

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50 Table B.2. Summary of Pavement Condition Data Condition Survey/Smoothness Testing Year Friction Testing Year Existing Pavement Condition Parameters 1999 2002 2005 2008 2000 2004 2008 PCR Northbound (NB) 95 92 89 84 Southbound (SB) 98 96 93 88 Polishing (% wheel path area) NB 1.8 5.2 22.4 63.0 SB 0.9 4.5 24.8 58.4 Trans-joint seal damage, LS (joints/mi)a NB 56 102 123 103 SB 45 110 145 122 Trans-joint seal damage, MS (joints/mi)a NB 5 63 93 143 SB 2 48 85 156 Trans-joint seal damage, HS (joints/mi)a NB 0 8 15 38 SB 0 2 21 30 Long joint seal damage, (ft/mi)b NB 0 56 287 784 SB 0 108 402 1,026 Trans-joint spalling, LS (joints/mi)a NB 2 9 23 42 SB 0 4 15 21 Trans-joint spalling, MS (joints/mi)a NB 0 1 5 22 SB 0 0 1 11 Long joint spalling, LS (ft/mi)b NB 14 25 54 130 SB 10 24 48 164 Long joint spalling, MS (ft/mi)b NB 0 2 38 116 SB 0 0 29 84 Corner cracking, LS (slabs/mi) NB 0 2 3 5 SB 0 1 1 3 Corner cracking, MS (slabs/mi) NB 0 0 1 3 SB 0 0 1 2 Transverse cracking, LS (slabs/mi) NB 0 2 3 5 SB 0 0 0 2 IRI (Average Std Dev) (in./mi) NB 88 7 106 5 113 6 120 5 SB 86 6 97 5 106 8 114 5 FN40S (Average Std Dev) NB 35.2 4.6 32.4 3.9 28.8 2.0 SB 36.1 5.5 35.0 4.5 31.4 3.6 a Out of 352 total transverse joints/mi. b Out of 10,560 ft/mi (longitudinal lane-shoulder joint and longitudinal lane-lane joint).

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51 Limited partial- and full-depth patching, ultra-thin bonded ficiently impacted by the climate in terms of durability. Also, wearing course; and the treatment performance and closure duration require- Limited partial- and full-depth patching, thin HMA overlay. ments appear to be satisfied by all four treatments. Hence, based on this analysis, it is reasonable to proceed with a cost- effectiveness analysis that includes all four combination Final Feasibility Analysis treatments. Evaluating these four combination treatments using the fea- sibility matrix in Table 3.5, it can be seen that none are suf-