Maintenance and Surface Preparation Activities Prior to Pavement Preservation Treatments (2021)

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17   Overview To better understand the current pavement maintenance and surface preparation practices that state transportation agencies employ, a survey of practice was developed, pre-tested, revised, and then distributed to each of the 50 state DOT voting members of the AASHTO Committee on Maintenance. The survey materials asked recipients to forward the survey to the appropriate person if the voting member was not the best person to represent and describe the agency’s relevant practices. In addition, email reminders encouraged participation in the survey. These efforts and respondent cooperation resulted in completed surveys from 45 states—a 90% response rate for the state DOTs. This chapter summarizes the findings from the survey of state DOT practices. The informa- tion is presented in several formats, including tables and graphs as appropriate. Appendix A includes a copy of the survey questions that were distributed electronically. Appendix B details the state survey responses, including any expanded responses (every survey question offered an Other option or space to further explain the response). Survey Content The survey questions were organized into the following three categories: • Planning – Initial survey questions requested information about how the DOT planned for preliminary maintenance or surface preparation prior to constructing a preservation treat- ment. Specifically, the survey asked agencies whether the decision was driven by policy, whether decisions were made within the agency, and whether and when maintenance or surface preparation actions were planned in relation to the timing of preservation treatment installation. • Implementation – This survey section inquired about how the state conducted maintenance and surface preparation actions preceding the preservation treatment installation. The survey also asked each agency to describe funding mechanisms and to explain how the preliminary work would be accomplished when the preservation treatment is installed either by agency forces or by contract. Questions also explored reasons why the work may not be completed as planned. • Tracking – The questions in this survey section focused on how maintenance and surface prep- aration work may be tracked for use within the maintenance management system (MMS) or pavement management system (PMS) to refine performance modeling and cost predictions. The survey responses are presented and discussed in the remainder of this chapter. Each graphic depicting the responses includes a notation N = x, where x equals the total number of agencies N responding to that question. The number of responses for each option is included C H A P T E R   3 State of the Practice

18 Maintenance and Surface Preparation Activities Prior to Pavement Preservation Treatments in the bar or pie sections of each of the graphic. If the sum of the responses exceeds N, then the question gave agencies the option to select multiple answers. The survey team also used the results to identify state DOTs willing to share their experience in greater detail. These case examples are detailed in Chapter 4. Survey Results: Planning for Pavement Maintenance and Surface Preparation Throughout the questionnaire, the responding DOTs identified different processes for plan- ning pavement repairs, maintenance, and surface preparation in conjunction with pavement preservation projects. For background, the agencies specified the maintenance applications that were applied, available guidance on maintenance and surface preparation ahead of preservation, and timing of the maintenance actions in relation to the preservation treatment. The surface preparation items did not specifically include work such as sweeping, other cleaning, or tack application that are common initial steps in any edge-to-edge pavement preservation project. Maintenance Treatments Applied Survey questions inquired about agencies’ experience with common maintenance treat- ments applied on flexible and rigid pavements. As shown in Figure 3, for flexible pavements, the most commonly cited treatment was crack sealing and filling, followed closely by partial-depth patching. Full-depth patching and rut filling also were noted by a large number of respondents. Fewer survey respondents indicated experience in correcting grades or slopes, making drainage repairs, or applying other treatments. As shown in Figure 4, typical maintenance actions for rigid pavements included full-depth repairs and then partial-depth repairs. Joint resealing also was one of the most commonly identified treatments. Additional survey responses included diamond grinding, crack sealing and filling, drainage repairs, and, less frequently, cross-stitching. Some agencies observed that diamond grinding was the most common preservation activity performed on concrete pave- ments, so the other repair strategies would precede diamond grinding. Several agencies indi- cated that they had very few or no concrete pavements. Figure 3. Treatments used for maintenance or surface preparation on flexible pavements.

State of the Practice 19   A description of the current state of the practice also necessitated knowledge about how deci- sions are made within the agencies to implement maintenance and pavement surface prepara- tion strategies prior to preservation treatments. As illustrated in Figure 5, a nearly even split occurred between those agencies that developed the scope of repairs and surface preparation during the scoping session for the pavement preservation project and those agencies that relied on local assessments by each maintenance office and acted on those assessments before the pres- ervation project. About a third of the DOTs indicated that the maintenance and surface prepara- tion strategies are linked to the specific preservation treatment being designed, and five DOTs reported that maintenance actions are not connected to the preservation treatment that may follow. Fewer noted a formal policy that directs maintenance or surface preparation actions. One DOT observed that its decisions could be both based on policy or directed locally because the district has access to a patching contract that may be used to conduct work on any route, but such work may also be included as a pre-treatment in the preservation contract. One agency specifically referenced its one-touch policy, which requires the district maintenance manage- ment team to complete at least one “maintenance” operation on a route prior to preservation activities to extend the time before the preservation treatment is required. Another agency noted Figure 4. Treatments used for maintenance or surface preparation on rigid pavements. Figure 5. Varying ways that maintenance decisions are made.

20 Maintenance and Surface Preparation Activities Prior to Pavement Preservation Treatments that its specification requires crack sealing and filling before any preservation project, but other activities may be scoped ahead of the preservation project. As decisions are made to conduct maintenance and surface preparation, the planned timing of the activities is important to consider. Some agencies, for instance, encourage a 60- to 180-day curing period between the application of a crack sealant and the placement of a chip seal treat- ment. The thought is that curing time reduces the likelihood of the crack treatment bleeding through the seal. For other treatments, a curing period may not be as important. Figure 6 breaks down the responses on when agencies plan to apply maintenance and surface preparation. Most responses indicated that maintenance could occur at any time in advance of treatment, with far fewer respondents reporting that timing depends on which treatment is applied. Even fewer agencies noted a minimum amount of post-maintenance time before preservation would be applied. If an agency indicated that a specified time interval was required between the application of maintenance and the preservation treatment, the survey asked the agency to quantify that time period. Those responses, although limited in number, are shown in Figure 7, ranging from less than 6 months to between 1 and 2 years. Several agencies stated that it may not always be prac- tical to require a significant time interval between treatments and that maintenance and surface preparation may be part of the preservation contract, so the contractor controls the timing. As shown in Figure 8, in almost every responding agency, decisions are made at the local level for maintenance and surface preparation activities; the central office contributes to the decision in just less than half of the responding agencies. This combination implies that project planning for preservation activities is highly collaborative; many states mentioned multidisciplinary teams Figure 6. Timing constraints for maintenance work. Figure 7. Target time intervals for advance work.

State of the Practice 21   that review each project to determine the best approach. In some agencies, maintenance activ- ities are directed locally while surface preparation activities may be guided more by central office policy or design procedures. Survey Results: Implementing Pre-Preservation Pavement Maintenance and Surface Preparation After the pavement maintenance and surface preparation work is planned, it is performed either by internal DOT forces or by a contractor using construction contracting methods. This section focuses on how agencies perform the work. Questions cover how the work was funded, how the work was installed, and how the preservation project was planned. Funding Mechanisms for the Work After preventive maintenance became eligible for federal funding, several states began using federal funds to support their pavement preservation programs (Figure 9). Predominantly, however, responding agencies funded their maintenance work through state or agency monies. According to the survey, some agencies may use federal funds to support surface preparation Figure 8. Responsible office for decision making. Figure 9. Maintenance work funding source.

22 Maintenance and Surface Preparation Activities Prior to Pavement Preservation Treatments work for certain types of preservation projects. For example, surface preparation for a mill and inlay preservation project may be financed by federal funds while this might not be the case for a treatment such as a slurry seal. South Carolina reported that the roadway classification determines the funding source, with interstate projects using federal funds and projects on all other routes relying on state allocations. States also observed that the urgency of completing the project may drive the decision on a certain funding type because federal funding, in their experi- ence, requires more lead time to develop and authorize a project. Performance of Preliminary Maintenance and Surface Preparation Preliminary maintenance and surface preparation work may be accomplished by internal agency personnel or by contract. The choice often is linked to whether the pavement preser- vation project is constructed by in-house forces or under contract. This section also considers the scope of maintenance work executed before preservation and addresses whether all needed maintenance is completed. Preliminary Work Quantity As shown in Figure 10, agency responses were almost evenly split on whether the scope of preliminary maintenance applied in advance of a preservation treatment was limited. Many of the explanations from those agencies answering “yes” focused on whether the pavement condi- tion required substantial maintenance work and whether it should still qualify for pavement preservation. If a roadway deteriorated and required a significant amount of maintenance prior to the treatment, rehabilitation might be a better alternative than pavement preservation. Agencies cited limits for preliminary patching of between 5% and 10% of the pavement. One agency stated that if a threshold of 10% of the surface were exceeded, a life-cycle cost analysis could be performed to determine whether pavement preservation was still cost-effective. Other agencies that answered “yes” indicated that the available budget may limit the amount of preparatory maintenance or surface preparation work that could be completed. The explanations associated with the “no” responses noted that the scope of maintenance must be reasonable and that, in the absence of official policy, good judgment is still required. One agency specifically pointed out, “If a pavement condition survey supports preservation, there should not be a substantial amount of pre-treatment maintenance work needed.” Is the Amount of Preliminary Maintenance Limited? Figure 10. Agencies reporting limits on the permitted amount of preliminary maintenance work.

State of the Practice 23   Preservation Treatment Installed by Agency Forces As depicted in Figure 11, nearly half of the agencies indicated that in-house forces would conduct surface preparation and maintenance work if they also implemented the final pres- ervation project. Several agencies reported that the question did not apply or that the work would be completed under a different preservation contract. Several states do not use in-house personnel to apply edge-to-edge treatments. Other agencies explained that their decision on how to carry out this work depended on the type of treatment called for, the complexity of the treatment, or the experience level of the in-house crews that do the work. Still other respondents described flexibility within their program so that either method could be used to perform the pre-treatment work. Preservation Treatment Installed by Contractor Figure 12 breaks out agency responses to the question on how maintenance and surface prep- aration work was completed when the preservation project was accomplished under contract. According to almost half of the respondents, the preservation contract included preliminary work; far fewer reported that in-house crews performed the work before a contractor installed the preservation project. Several other responses observed that the method was not always consistent and could vary based on the scope and timing of the project and on the type of Figure 11. Responsibility for application of maintenance work before agency-applied preservation treatment. Figure 12. Responsibility for application of maintenance work before contract-applied preservation treatment.

24 Maintenance and Surface Preparation Activities Prior to Pavement Preservation Treatments treatment being applied—or that either option could be used to deliver the work. For example, a few agencies mentioned the method for conducting the crack sealing activity. Accordingly, crack sealing could be installed by assigning in-house crews, using an on-call maintenance contract, or including crack sealing in the pavement preservation contract itself. Only one agency responded that it did not contract out any preservation work. Installation Reliability Even though maintenance work and surface preparation may be planned and included in the contract documents, they may not always be carried out according to the plan. In response to the question about whether planned maintenance work always occurs, almost two-thirds of the agencies answered “no.” Respondents noted explanations such as the agency lacked proper over- sight to accomplish the work; the engineering inspector or project designer might not possess the required skill to identify needs; or significant time may elapse between the scoping and the start of construction, allowing the roadway to further deteriorate. One respondent advocated denoting repair quantities and locations in the plans. The basic breakdown between “yes” and “no” responses is shown in Figure 13. However, Figure 14 displays the most commonly cited Does Planned Maintenance Work Always Occur? Figure 13. Responses to whether planned maintenance is always completed. Figure 14. Factors preventing completion of planned maintenance.

State of the Practice 25   factors that prevented maintenance work or surface preparation, with available budget for the work topping the list. Regardless of whether planned maintenance work or surface preparation is performed, any work that is completed should be captured and incorporated into pavement models and future maintenance planning. Survey Results: Tracking the Work Of the 45 responding state agencies, only a small number indicated that maintenance work and surface preparation work were not captured in a management system for assessment and consideration (Figure 15). The highest number of responses reported that the work was tracked in either the maintenance management system or the pavement management system. Figure 15 also documents that almost one-third of the responses split between some other process or a tracking process that depends on whether the work is done by in-house forces or under contract. Explanations for the latter included different tracking systems; the maintenance management system monitored in-house work efforts while contract work was tracked in the construction management system and perhaps the pavement management system. Figure 16 identifies the project characteristics tracked during maintenance and surface prepa- ration work. Most responses specified that location, costs, materials, labor, and equipment are commonly monitored within the agency system. However, the information tracked may not be the same within the agency or may not be compatible with both the maintenance manage- ment system and the pavement management system. For instance, the location scheme that the maintenance management system uses to track a patching or crack sealing activity may not align with the roadway segments monitored in the pavement management system. In addition, by their very nature, maintenance activities tend to be localized rather than performed over the entire pavement segment to which they are assigned in management systems. Dual management systems require a link or an export/import process to include maintenance management system activities in the pavement management system. Agencies reported that the information in the construction management system was not coded in a standard format for easy inclusion in the pavement management system, and the construction management system itself was perhaps not easily searchable. Roughly a quarter of the respondents indicated that performance was tracked, but only one specified that such tracking was in the pavement management system. Another comment suggested Figure 15. Process used to track maintenance work.

26 Maintenance and Surface Preparation Activities Prior to Pavement Preservation Treatments that the information in the systems is not always timely. Pavement condition data from the most recent survey may be relatively old, so the maintenance forces may be responding to identified needs while other personnel are planning to make the repairs as part of a preservation contract. Summary Responses to the questionnaire expose a great diversity in the strategies that agencies use to complete maintenance and surface preparation prior to the application of preservation treat- ments. Few agencies complete all the work themselves, and some contract out most or all of such work. Most DOTs have the flexibility to implement their pavement maintenance and surface preparation work in multiple ways. They may conduct some work using in-house personnel and other work under contract. These agencies have developed their practices to succeed within their specific circumstances and context, but their responses reveal an openness to improve. Figure 16. Characteristics tracked during maintenance and surface preparation.