Pavement Patching Practices (2014)

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44 This chapter presents case examples of agencies that either illustrate common most effective practices or are trying new approaches. These case examples were identified through the survey responses and explored through follow-up interviews, e-mails, and a literature review. MAINTENANCE QUALITY ASSURANCE PROCESS—INDIANA DEPARTMENT OF TRANSPORTATION Although many states have management programs that include pavement patching, the one used by INDOT requires post- installation inspections by trained rating panels. INDOT’s Maintenance Quality Assurance Process (77) covers nine maintenance activities that are considered to have a major impact on roadway performance. Two of these activities are shallow patching and deep patching, which are performed on both asphalt and concrete pave- ments. These activities are reported by the maintenance units that perform them, and QA inspections are performed by teams of trained raters—one team in the northern part of the state and another in the south. Annual reports are prepared that compare the performance of the maintenance activities across the state. These inspections and the reports are used to revise the standards and to improve the patching practices. In some cases, they have been used to explore why patching performs better in some places than in others; so far, this has mainly come down to techniques rather than materials. The need to patch is determined by field inspection or public complaint. Each of the state’s six districts has a pave- ment engineer who is responsible for all pavement-related activities in the district. The pavement engineer is familiar with the roads in the district and determines where work is needed. A maintenance subdistrict foreman may also identify the need for attention. Some maintenance contracts are let; however, the majority of the work is done with state work- forces, especially on asphalt surfaces. As defined by INDOT, shallow patching is “minor patch- ing of small areas of bituminous roadway or paved shoulder with hot or cold bituminous mixtures with hand tools to cor- rect potholes, edge failures, and other . . . hazards” (77). This work is performed by the maintenance units. Holes that are more than 1 in. deep and 12 in. in diameter are supposed to be repaired as soon as possible. Smaller holes do not require immediate attention but must be filled by November 1 to pre- vent further damage. The standards suggest that if there are many holes in an area, there may be a larger problem that cannot be addressed simply by patching. Deep patching is more extensive patching to repair base failures, blowups, or settlements, which can occur on concrete or asphalt pavements and paved shoulders. Deep patching requires the removal of the pavement full depth. The district pavement engineer advises if a deep patch is appropriate and makes recommendations on the type of repair. The equipment requirements are more extensive than for shallow patching and include saws, jackhammers, and backhoes. As with shal- low patching, the standards include details on preparations, scheduling, traffic control, and materials. Each district has at least one spray patcher, and one district owns a paver; the paver is lent out to other districts or those districts rent equipment when needed. The district pavement engineer decides when to use the paver instead of manual patching. There are also asphalt storage trailers (hot boxes) in each district. Small rollers or vibratory plates are used for compaction on semi-permanent patches; truck tires are typi- cally used for reactive patching (the throw-and-roll technique). Traffic control is as outlined in the department’s Work Zone Traffic Manual (78). The performance standards include details on the type of patch, surface preparation, scheduling, traffic control, type of material to use, typical crew sizes, and more. The throw-and- roll technique is recommended for winter and early spring repairs. Vibratory plates or rollers are used to compact semi- permanent patches. Cold mix (generic or proprietary) is used as a temporary repair when needed; this is typically used for cold weather repairs when the asphalt plants are shut down. Proprietary chapter five CASE EXAMPLES

45 stockpile mix is not commonly used because of difficulties in bidding out proprietary materials; in general, the state strongly prefers non-proprietary materials. The choice of material to use for patching concrete pavements also depends on the time of year, location, type of roadway, and how long a lane can be closed. An approved list of materials is maintained. If a temporary patch is placed, it is scheduled for replace- ment with hot mix as a permanent patch within months after the plants reopen. Work plans are made for each fiscal year that lay out the work to be performed month by month. Tem- porary patches on both types of pavements are expected to last 3 to 6 months; permanent patches should last as long as the surrounding pavement. INDOT has found that spray- injected patches can perform as permanent patches if properly installed. For both shallow and deep patching, the locations are tracked by roadway segment. A planned upgrade will tie this to reference posts; however, this will require changing the maintenance management software. The work management system tracks activities to record how much work of various types is done and where it is performed. Follow-up inspections are performed by the rating teams. Shallow patching is inspected between 30 and 45 days after completion. Deep patching is inspected between 30 and 45 days after completion and again after one year. Not every roadway is inspected; however, one road in each maintenance subdistrict is inspected each year. Rating forms assign points for shallow patching based on how many holes were patched, are flush with the surrounding pavement, are compacted, have loose material present, and exhibit tracking. Deep patches are scored based on whether the patches are square with the pavement, cover the distressed area, are flush, and are compacted. In addition, for patches greater than 100 feet in length the pavement markings must be reestablished to get maximum points. The inspection also looks for evidence of poor drainage. This program has been in use for many years and is perform- ing well. It provides needed information to revise practices to get the most effective performance from these maintenance activities. TOOLS FOR TRACKING PATCHING— WASHINGTON STATE DEPARTMENT OF TRANSPORTATION GPS and GIS systems are increasingly being used in every- day activities, and advancements in technology now make it feasible to use these tools for even more undertakings. Sev- eral states, including Arkansas, Louisiana, and Maryland, are exploring the possibility of using GPS and/or GIS to track maintenance events or are planning to incorporate the tech- nology in their programs in the near future. Washington State has already begun implementation of an internally developed system that uses GPS to track locations that can be tied to their strong GIS program. Washington’s Highway Activity Tracking System is used to track a variety of maintenance activities, including patch- ing (79). The system currently allows agency personnel to input the results of inspections to identify maintenance needs and to log the repairs. The needs and repairs can be linked in the system so that tracking the responses to patching needs can be performed. Handheld GPS units are being imple- mented to accurately pinpoint where the repairs are needed and performed. The department believes recording an accu- rate location is the key to enabling meaningful analysis of the success of the maintenance. Information recorded includes the reason for the repair, type of repair, and location including which lane (or shoulder) is patched. The system is not currently used to track the patching material used; however, this is a planned future enhancement. The integration of GPS in the system is described as “a work in progress”; however, it is available statewide and is being used often in some regions. There is coordination and training provided by the headquarters, and training has been performed on a regional basis. The future of the system is promising and its use is expected to increase as more regions receive the training and become familiar with the capabilities of the system. PROCESS FOR ADDRESSING POTHOLES— MARION COUNTY, OREGON Marion County, Oregon, the county surrounding the state capi- tal of Salem, is an example of a local agency with established pavement patching and other maintenance programs (80). The Marion County Public Works (MCPW) department has written guidelines for pothole patching that include reporting potholes and setting priorities for patching. They describe a process for addressing potholes termed “The Four R’s: Response, Rating, Reporting and Repair.” The response is an alert that a pothole has been detected. If the alert comes from a citizen or another agency, such as law enforcement, the MCPW dispatcher collects information about the location of the pothole and records it in the dispatch

46 log, assigning an “event number.” Trained personnel from the department will then visit the site and assess the severity of the pothole and the need for traffic control when making the repair. If the alert comes from MCPW staff, no visit to the site is needed as the staff member can provide the needed location, severity, and traffic control information to the dis- patcher. Traffic control may require flaggers, lane closures with cones or arrows, and flashing lights on equipment. Bar- riers are sometimes used for longer lane closures by contrac- tors for planned patching. The rating is performed by MCPW personnel according to a chart summarizing the Pothole Severity Criteria Matrix Guidelines (80). The guidelines rate the severity of distresses on paved roadways, shoulders, and gravel roads. On paved surfaces, the severity is rated based on size of distress (width, length, and depth); roadway information, including classifica- tion, speed, and available driver response time; and location, in wheelpaths, in travel lanes, or anywhere on the pavement. Photographic examples are provided to assist the raters in assessing severity. High severity potholes are “large enough to do significant damage to tires, rims, suspension or axles”; the guidelines call for repairing these potholes as soon as pos- sible. Typically, the department reports, emergency patches are placed within a day. Medium severity patches have the potential to cause tire or rim damage; the guidelines suggest these be repaired within three business days, weather permit- ting. Low severity potholes will probably not cause damage to vehicles and are scheduled for repair when routine patch- ing is performed. Reporting is done after the pothole severity is rated; this step involves feedback to the dispatcher with the location (by street, address, or mile post; nearest cross street; and/or lane), pothole severity, and need for traffic control. Repairs are scheduled based on the severity rating, as described earlier. The materials used include bagged cold mix for temporary patches and cold mix placed in a heated enclosed truck bed or a “hot-patch truck.” (The county has no concrete surfaced roadways.) The hot-patch truck allows for essentially permanent repairs to be made. The dispatcher is informed of repairs after they have been completed and records them in a log. This also allows for monitoring the quality of the patching and materials, since the repair is well- documented. Patching is a major activity for this county, and agency personnel perform patching on an almost daily basis. Staff not only places patches on the county network, but also per- forms patching for other jurisdictions. Paving and specialty contractors are used on occasion. Although this county has an established program for managing pothole patching they still see room for improve- ment. They specifically cite needs for more information on and understanding of the performance of different patching materials, development of new materials, development of new equipment, and the use of bonding agents. They report that the greatest needs are for better tack application and tools for patching. EXAMPLE OF A PATCHING TRAINING PROGRAM—CORNELL LOCAL ROADS PROGRAM, NEW YORK The Cornell Local Roads Program in New York has provided training on pavement maintenance since 1996. That training has continued and been upgraded over the years. The latest version of the workshop was first offered in 2005 in response to issues in the state regarding selection of the right mainte- nance strategy for a given situation (81). The focus of the workshop is on understanding the causes of distress so that the proper repair technique can be selected. The course covers repair of paved and, to a lesser extent, unpaved roads and a variety of repair techniques, with an emphasis on the most common treatments, including patch- ing, crack sealing, and chip seals. To foster deeper understanding of the right repair technique to use in different situations, the course starts out explaining how roads carry loads and what causes them to fail. Class- room demonstrations explain fatigue, and discussions describe other failure mechanisms and contributing factors. The causes of a failure may arise from design, construction, materials, or maintenance. The types of distress and what causes them are also presented. Once failure has begun, the choice of what to do about it ranges from doing nothing to total reconstruction, with a number of maintenance options in between. The types of maintenance activities are outlined in Table 9. Demand maintenance is done in response to a hazard or complaint, referred to in this synthesis as reactive patching. Pothole repair is a typical example of demand maintenance. A semi-permanent patch is considered corrective mainte- nance because it is planned to correct a failure after it has occurred. The appropriate times in a pavement’s service life at which to apply these different types of maintenance are discussed in the course. One chapter in the pavement maintenance manual is devoted to patching, including the reasons to patch and types of patches (semi-permanent, spray patching, and demand

47 patching with cold mix). Step-by-step instructions on best practices for each of these types of patches are provided. Lastly, cost-effectiveness of the various types of patching is discussed. Table 10 summarizes the costs of different demand patching materials and procedures. The point being made is that even with higher costs for labor and equipment taking the time to roll the patch improves the performance. Higher costs for proprietary patching mate- rials can also be justified based on their improved service lives. The course has been offered 45 times since 2005. There have been 800 participants, including individuals from cit- ies, towns, and villages; the state; counties; federal agencies; and commercial or private entities. The course is meeting a state need. Type of Maintenance Planned? Performed Before Deterioration? Extends Pavement Life? Demand No No Not necessarily Routine Yes Not necessarily Sometimes Preventative Yes Yes Yes Corrective Generally No Yes Source: Orr (81). TABLE 9 TYPES OF MAINTENANCE ACTIVITIES Method Throw-and-Go (standard cold patch) Throw-and-Roll (standard cold patch) Throw-and-Roll (proprietary cold patch) Price ($/ton) $45 $45 $72 Materials $900 $900 $1,440 Labor $676 $901 $901 Equipment $200 $267 $267 Initial Cost $1,776 $2,068 $2,608 Survival Rate 10% 25% 50% Total Cost* $4,813 $4,782 $4,564 Source: Orr (81). *Assuming failed patches must be replaced three times. TABLE 10 COSTS OF DIFFERENT PATCHING TECHNIQUES