Rapid Slab Repair and Replacement of Airfield Concrete Pavement (2021)

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7   Planning Thorough planning is essential for the success of any RSRR project. This process begins by identifying an individual or team (depending on project size) to oversee the planning process. There are six key steps in a typical planning sequence for RSRR projects (Figure 4). The level of effort within each step will vary from airport to airport according to the airport size, type, function, and available resources; experience with RSRR; and the quantity and location of RSRR work. For example, Steps 2 and 3 are more applicable to airports that do not regularly perform or have not performed RSRR, whereas those two steps may be skipped by airports that have extensive RSRR experience or established programs. While airports will develop individualized approaches to planning, the general planning sequence remains the same. Identify Need for and Extent of Partial- and Full-Depth Repair Work Selecting applicable and effective maintenance treatments depends on factors such as exist- ing distress, facility type, climate conditions, available materials, and access to experienced personnel to conduct the work. The steps are 1. Conduct a detailed pavement assessment to identify concrete pavement distresses (type, extent, and severity). 2. Determine whether PDR or FDR is the proper repair strategy for the observed distresses. 3. Document the size and location of proposed PDRs and FDRs. One or more of the following methods (listed in order of increasing amount of inspection detail and required resources) may be used to determine whether concrete slabs need repair or replacement (either PDR or FDR): • Visual pavement inspections carried out by airport personnel on a regular basis: – For Part 139 airports, guidance is provided in FAA AC 150/5200-18C, Airport Safety Self-Inspection (FAA 2004). – For non–Part 139 airports, pavement-related inspection guidance listed in FAA AC 150/ 5200-18C can be useful, albeit on a less frequent inspection schedule. • Pavement surface evaluation and rating of specific pavement areas per FAA AC 150/ 5320-17A, Airfield Pavement Surface Evaluation and Rating Manuals (FAA 2014a). Addi- tionally, FAA AC 150/5380-6C, Guidelines and Procedures for Maintenance of Airport Pave- ments (FAA 2014b) provides guidance on the inspection of pavements and identification of concrete pavement distresses. • Detailed inspection of pavement condition, carried out according to ASTM D5340, “Standard Test Method for Airport Pavement Condition Index Surveys.” This method must C H A P T E R 2

8 Rapid Slab Repair and Replacement of Airfield Concrete Pavement be expanded to the entire pavement area of interest to determine locations and quantities of PDRs and FDRs. If data are being collected specifically for an RSRR project, the pavement condition index (PCI) does not need to be calculated, as the location and extent of distress are more important. Detailed distress mapping, which can often incorporate geographic information system data for locating and tracking repairs, is suggested. • Information extracted from an Airport Pavement Management Program populated with data collected according to ASTM D5340. These programs, however, are often based on statis- tical analysis of sample units, which may not accurately identify the actual repair quantities. Following are examples of approaches for determining the need for PDR and FDR: • John Glenn Columbus International Airport: A pavement condition assessment is per- formed on an annual basis and used to determine PDR quantities. The airport operations group determines whether an emergency repair is warranted. • Louisville Muhammad Ali International Airport: Visual pavement inspections are performed on a regular basis, and the airport has established thresholds for cracking and spalling dis- tresses that trigger repair strategies. • McCarran International Airport (Las Vegas): Weekly inspections are performed to identify locations that require PDR and FDR. If areas that need PDR are identified, they are pro- grammed for repair the following week. Locations that warrant FDR or other major repairs are discussed with FAA on a weekly basis to program the repairs. One highlight of the program is that the cause of failure is investigated to identify the correct repair strategy and minimize the chance of repeat failures. • Raleigh–Durham International Airport: A pavement management system is used to track distresses, the PCI, and deflection measurements to evaluate structural capacity. Airport personnel use the pavement management data to track performance and identify areas for repair. Pavement condition surveys are conducted on one-third of the pavements each year. • Seattle–Tacoma International Airport: One-third of the airfield pavement assets (e.g., runways, taxiways, taxilanes, and aprons) are inspected each year. These data are integrated into a 5-year pavement management program that is used to prioritize pavement work. Consider Conventional Versus Rapid Construction The selection of the construction technique to be used for PDR and FDR application is driven mainly by the location of work on the airfield, the impact on airport operations, and the allowable closure time. Rapid construction is not always necessary and, before deciding on a construction technique, it is essential to Figure 4. Planning sequence. Source: Nichols Consulting Engineers, Chtd.

Planning 9   1. Develop a basic understanding of the differences between conventional and rapid PDR and FDR construction and 2. Understand the challenges associated with rapid PDR and FDR construction. Considerations for selecting conventional or rapid construction techniques include overall approaches, construction duration, and typical materials, among others. Construction Approaches Conventional construction relies on common construction techniques and equipment, standard work hours, and readily available materials. Equipment and materials (e.g., concrete mixtures) are widely available because they are used on local and regional construction projects (nonairport as well as airport projects). In comparison, rapid construction requires accelerated techniques, constrained work periods, backup equipment, and, often, concrete mixtures or repair products with early strength gain characteristics. Table 1 summarizes typical features of conventional and rapid construction approaches. Duration of Construction The duration of construction varies for PDR and FDR but is typically governed by the time required for the conventional portland cement–based materials to achieve the required strength for opening to traffic (i.e., 5 to 7 days or more). Rapid construction is generally carried out in a short time window during specified hours (nighttime, off-peak hours, weekend, or multiday/multiweek closures). Some closures for emer- gency PDR may be less than 2 hours, depending on the location of the pavement (e.g., runway). See the definitions provided in Chapter 1. Feature Conventional Construction Rapid Construction Materials, techniques, and equipment Contractors are familiar with materials and techniques. Initial learning curve, as contractors may not be familiar with early-strength concrete materials and techniques. Fewer contractors have the necessary experience. Materials and equipment are readily available. Requires specialty or less-common concrete mixtures and repair materials. Concrete mixtures require several days to gain required strength for opening. Concrete mixtures can gain sufficient strength to open in less than a day or even within a few hours (shorter closures). Operational impact Larger impact on aircraft operations (depending on airfield location). Reduced impact on aircraft operations (depending on airfield location). Final product Tends to have better workmanship and final product. Workmanship and final product quality can suffer as a result of accelerated schedule. Cost Costs in line with industry standards for similar work. Often higher costs (as compared with conventional construction). Service life Service life in line with industry standards for similar work. Service life is often shorter (as compared with conventional construction). Source: Peshkin et al. (2006), FAA (2007), Priddy et al. (2013), Priddy (2015), and data collected during this project. Table 1. Typical features of conventional and rapid slab repair and replacement construction.

10 Rapid Slab Repair and Replacement of Airfield Concrete Pavement Typical Materials Although specific materials are not selected during the planning process, it is important to have a general understanding of the common material types for airfield PDR and FDR. Table 2 summa rizes typical materials used for PDR and FDR along with typical timing for opening to traffic. For material selection, Smith et al. (2014, p. 115) recommend “to use the least exotic (i.e., most conventional) material that will meet the opening [to traffic] requirements.” It is important to consider the candidate material types used for PDR and FDR when planning the allowable closure times, especially if there is flexibility in closure times. If closure times for specific airfield pavements are already established (i.e., not flexible), PDR and FDR materials should be selected that achieve specified strengths within the allowable time constraints, including the time for construction. Considerations Proper remediation of poor subgrade may not be feasible during rapid construction, depending on the duration of closure (i.e., overnight, full-day, or weekend closures). The extent of required subgrade remediation should be considered when the duration of closure and need for rapid construction are being evaluated. Other considerations that typically drive the decision to use rapid construction include • Construction impact: Operational impacts (associated with the work location) almost always drive the decision to use rapid construction. • Cost: The costs can be considerably higher than conventional construction costs because of accelerated schedules and the use of specialty materials. • Performance: Increased risk of premature failure or shortened service life is inherent in rapid construction. Table 3 expands on these points. The order of importance varies depending on the size of the airport. For example, construction impact is likely the most important factor for airports with Construction Approach RSRR Type Typical Materials Timing of Typical Return to Service After Installation Conventional PDR Conventional concrete or mortar materials. ≥3 days FDR Conventional concrete (e.g., P-501 or local concrete mixture, if permitted). ≥7 days Rapid PDR Specialty VHES materials with cementitious or noncementitious binders. Typically, proprietary, prepackaged materials with specific blending processes. ≤4 hours HES or MES portland cement–based concrete mixtures with an ASTM C494 accelerating admixture, a higher amount of portland cement, or a combination of both. 6–36 hours FDR Commercially available ASTM C1600 VHES cements (critical pavement areas with very short closure windows). ≤4 hours HES or MES portland cement–based concrete mixtures with an ASTM C494 accelerating admixture, a higher amount of portland cement, or a combination of both. 6–36 hours Table 2. Typical features of conventional and rapid slab repair and replacement construction.

Planning 11   Performance PDRs and FDRs constructed using conventional techniques and materials inherently have lower risks of premature failure or shorter service life (Frentress and Harrington 2012, Hammons and Saeed 2010, Peshkin et al. 2006, FAA 2007). In comparison, accelerated construction comes with increased risk of premature failure and shorter service life. Factors that can lead to shortened service life include: • Poor workmanship. • Lack of experience with early-strength materials (e.g., improper mixing, handling, installing, and curing early-strength materials). • Shrinkage associated with some early-strength materials. • • Nighttime construction. Rushed nature of rapid construction. – Lack of contractor adherence to specifications. – Relaxed enforcement of project specifications. – Relaxed construction oversight. Factor Impact Construction Operational impact almost always drives the need for rapid PDR and FDR construction. • Conventional construction methods and materials are not an option for hourly, overnight, and full-day closures as these materials cannot achieve required strength (i.e., needed to support aircraft loads) in these time frames. • Weekend closures may permit the use of some aspects of conventional construction methods (e.g., daytime construction) and materials (e.g., conventional concrete with accelerators). • With proper planning, some pavement areas (e.g., aprons, taxiways with alternate routes, or runways at multirunway airports) may be candidates for the use of conventional construction methods and materials. Cost Accelerated schedules and use of specialty materials result in higher construction costs. • Seattle–Tacoma International Airport reports early-strength concrete can be up to 7 times more expensive than conventional concrete. • Vancouver International Airport reports the use of precast slab replacement for a pilot project was much more expensive than conventional cast-in-place but was a feasible alternative due to time restrictions. FAA AC 150/5370-16 (FAA 2007) lists the following factors related to increased cost: • Requirement for standby equipment and operators. • Increased contractor, inspection, and testing labor costs due to standard overtime and premiums for night and weekend work. • Lighting for night work. Additional factors increasing costs include: • Material costs for prepackaged materials used for PDR. • Material costs for HES materials used for FDR. • Added risk to contractor associated with accelerated construction. • Direct costs to airport (i.e., overtime for operations and construction personnel). • Larger workforce required. Table 3. Considerations for rapid PDR and FDR construction. significant commercial service. In comparison, cost may be more important to general aviation airports with limited budgets. Table 4 presents examples of service life reported by airports included in this study. Decide Whether Rapid Slab Repair and Replacement Is Necessary Table 5 provides criteria to determine whether RSRR is necessary. Once a selection has been made from Table 5, the flowchart presented in Figure 5 can be used to determine how to move forward. Ultimately, the decision to utilize rapid construction for PDR and FDR lies with each airport.

12 Rapid Slab Repair and Replacement of Airfield Concrete Pavement Airport Performance Life Hartsfield–Jackson Atlanta International Airport • PDR: 5 years McCarran International Airport • PDR: Several years; however, repairs get damaged during rubber removal • FDR: 3–5 years Phoenix Sky Harbor International Airport • PDR: 9 months to 3 years • FDR: Performs well and repair life not a concern Vancouver International Airport • FDR: >10 years Table 4. Reported service life for PDR and FDR. Evaluation of Need for RSRR Criteria Examples Necessary • Emergency PDR at any location. • Work location (PDR or FDR) will significantly affect aircraft operations or airport capacity (alternate routes may or may not exist). • Main runway or taxiway, aircraft parking location on apron or at a gate. • Single-runway airports. Considered • Nonemergency PDR at noncritical locations. • Work location (PDR or FDR) may inconvenience users with minimal impact on aircraft operations or airport capacity (alternate routes exist). • Runway when multiple parallel runways exist. • Secondary parallel taxiway; aircraft parking location on apron or at a gate. • Cargo apron. Not necessary • Areas that can be closed to aircraft traffic for an extended period with minimal to no disruption to operations (alternate routes exist). • Aprons. • Runway when multiple parallel runways exist. • Other noncritical concrete pavements. Table 5. Criteria for deciding whether rapid slab repair and replacement is necessary. Source: Nichols Consulting Engineers, Chtd. Figure 5. Rapid construction decision flowchart.

Planning 13   Coordinate with Stakeholders Regardless of the airport size and function, early engagement and continued coordination with stakeholders is an important planning element. This was identified by numerous airports surveyed during this project. Stakeholder coordination includes the following tasks: • Identify stakeholders. • Discuss project scope. • Solicit input from stakeholders. • Establish closure times and construction timing (i.e., preferred time of year or day of the week). Identify Stakeholders Stakeholders can be defined as groups or businesses on which the project will have an impact. Stakeholders may need to provide resources (e.g., airport operations), adjust flight schedules (e.g., airlines), or plan for impacts to business (e.g., tenants). Examples of stakeholders include, but are not limited to, the following: • FAA; • Control tower and ground control; • Airport operations, police, and aircraft rescue and fire fighting (ARFF); • Airlines; • Air cargo companies; • Tenants (e.g., fixed-based operators, flight schools, private hangars, charter services); • Ground services; and • Air National Guard (or other military operations at a joint-use facility). Discuss Project Scope While all details may not be available until later in the planning and design process (if appli- cable), it is important to inform stakeholders about the general project scope as soon as possible. Examples of discussion items include • Scope of work (e.g., PDR, FDR), • Work areas and closure limits, and • Duration and timing of work. Information can be initially conveyed in written format (e.g., letter or memorandum) to inform stakeholders about the upcoming project. However, as the planning and design process advances, meetings outlining the proposed plans and approach may be a more effective way to solicit and receive stakeholder input. Establish Closure Times and Construction Timing A key element of the planning process is establishing allowable closure times by RSRR loca- tion (e.g., runway, taxiway, apron) and construction timing (i.e., preferred days, months, etc.). Two cases exist: • Established closure times for different pavements on the airfield (i.e., runway, taxiway, apron) already exist. In this case, typical closure times should be identified and reviewed with stakeholders. • Established closure times for different pavements on the airfield do not exist. In this case, closure times will need to be established with input from stakeholders. While stakeholder input is important, the airport must ultimately make the final decision on preferred closure

14 Rapid Slab Repair and Replacement of Airfield Concrete Pavement times given the constraints. Selection of time must also consider weather conditions favorable for RSRR construction and materials to achieve the intended service life (i.e., short-term or long-term). All closure options for conventional slab repair and replacement or RSRR with longer con- struction time frames (1-day closure or weekend closure) should be fully investigated before an overnight closure option is considered (as previously discussed, materials and construction techniques associated with overnight closures are often more costly, and the risk of premature failure may increase). Depending on airport size, investigation into permitting longer closure times may require extensive coordination with stakeholders on such things as • Timing of scheduled flights and ability to adjust schedules; • Terminal gate access and aircraft parking positions; • Airside access to airfield tenants; • Alternate aircraft taxi routes around construction; • Alternate arrival and departure runways; • Loss of revenue to airport and tenants; • Emergency access routes for ARFF, police, and airport operations; and • Construction cost and quality. Factors to consider when discussing overall timing of RSRR construction include • Time of year with favorable weather conditions for construction; • Seasons with lower aircraft operations (passenger and cargo); • Times, days, weeks, or months with lower aircraft operations (passenger and cargo); • Conflicts with larger airport construction projects (i.e., schedule, location); and • Ability to simultaneously carry out work under a previously planned closure, which may require less overall stakeholder coordination. Table 6 provides examples of stakeholder coordination done by airports included in this study. Select Project Delivery Method Project delivery is the process and contract mechanism used to select the individuals or firm that will design and install the repair. Project delivery options for contractor-delivered projects include competitive bids, job-order contracting, executing a change order to existing contracts, Airport Description Hartsfield–Jackson Atlanta International Airport Coordinates extensively with stakeholders to identify closure times. Los Angeles International Airport Engages stakeholders early in planning and meets regularly with FAA and airline representatives. Louisville Muhammad Ali International Airport Coordinates significantly with all stakeholders by conducting preconstruction meetings and weekly go/no-go meetings with cargo carriers. Raleigh–Durham International Airport Coordinates with airline operations and works with them to determine flexible closure times. Holds monthly meetings with stakeholders to keep them informed and updated on the projects. Table 6. Examples of stakeholder coordination.

Planning 15   and soliciting quotes. A contract is not required when the work is performed by airport personnel. The main objectives and outcomes of this portion of the planning process are to • Decide who will perform the construction work (e.g., airport personnel or outside contractor) and whether a contract or agreement is required and • Evaluate options and determine the solicitation and contracting method to deliver the RSRR project. Figure 6 is a flowchart of the project delivery decision process. Decide Who Will Perform Construction Work An airport should first assess its ability to perform PDR and FDR construction work. The following factors can influence this decision: • Experience: Airport staff should have experience with the type of work (PDR or FDR) that is being proposed. Experience with FDR is rare outside of large hub airports. • Equipment: The airport must have proper equipment. PDR work requires certain equipment (e.g., jackhammers, concrete saws), some of which is specific to the selected repair material. FDR requires specialty heavy equipment (e.g., excavators, dump trucks, concrete screeds). • Staff availability: The airport must have sufficient staff with PDR or FDR experience available during the required time frame. • Project size: The airport must have available staff and equipment with which to complete the required number of PDRs or FDRs within the specified duration of the construction. Airports that do not have personnel with RSRR experience or the necessary equipment will need to hire a contractor for emergency and nonemergency PDRs and FDRs. Airports that do have both personnel with RSRR experience and the equipment necessary to complete the work may perform PDR and FDR themselves or choose to hire a contractor to perform the work. The following factors can influence this decision: • Urgency of the work: The airport survey responses indicated that most emergency PDRs and some nonemergency PDRs are performed by airport personnel. FDRs are rarely done in Source: Nichols Consulting Engineers, Chtd. Figure 6. Project delivery flowchart for rapid slab repair and replacement.

16 Rapid Slab Repair and Replacement of Airfield Concrete Pavement emergency situations, but a few large airports have the personnel and equipment to do this work in house. • Quantity of work: The surveyed airports tend to hire contractors for larger PDR projects. However, contractors generally perform all FDRs, even for projects as small as 1 to 2 slabs. • Availability of personnel: Airport personnel may not be available for RSRR within the required time frame. • Availability of equipment: The airport must have sufficient equipment available to complete the required number of PDRs or FDRs within the specified duration of construction. Materi- als and equipment may need to be procured well in advance of construction. Select Contract Type If the decision is made for a contractor to perform the RSRR work, a contract or agreement is necessary. Materials and equipment are normally provided by the contractor, but, in rare cases, the airport may provide the materials for the contractor to install. When a contract or agree- ment is warranted, four main construction solicitation and delivery approaches are common for RSRR projects: • Competitive bids as part of a traditional design–bid–build project delivery approach; • A change order to an existing contract for work at the airport; • Job-order contracting from a pool of on-call, prequalified contractors; and • Soliciting quotes from local contractors who have previously performed RSRR work at the airport (or at a similar airport). Table 7 provides more detail on the typical application of project delivery approaches. Table 8 provides examples of delivery approaches used successfully by airports included in this study. Identify Design Requirements Design requirements vary, depending on who will perform construction (i.e., contractor or airport personnel), the size of the project, and the type of construction contract. Design plans and specifications may be required, or a set of standard details may be utilized. The main objectives and outcomes of this portion of the planning process are to Type Application Notes Competitive bid Common method for nonemergency RSRR (any size project). Part of traditional design–bid–build project delivery. Change order to existing contract Feasible for nonemergency or emergency RSRR (smaller projects). Pricing may be higher than competitive bidding. Ensure the contractor or subcontractor has the proper experience to perform RSRR work on the airfield. Job-order contracting Nonemergency RSRR at airports with access to a pool of on-call, prequalified contractors (medium and larger projects). Generally available to airports that are owned or operated by agencies (e.g., cities, counties, or state transportation departments). Unit pricing for typical work items is commonly established in advance. Solicit quotes Emergency or nonemergency RSRR (very small projects). Reserved for cases when local contractors have previously performed RSRR work at the airport (or similar airport). Table 7. Types and applications of project delivery approaches.

Planning 17   • Decide the level and extent of design needed for the project (such as complete drawing sets or just standard or generic details) and • Determine who will perform design services (airport or consultant). Data collected for this project revealed the following trends related to the level of design for RSRR projects: • Construction is performed by airport personnel: – Design details and construction procedures may or may not be formalized. – Design details from previous RSRR projects are sometimes used. • Construction performed by contractors uses a combination of design documents (plans and specifications) and standard details/specifications; actual practice is a function of the project delivery approach: – Design plans and specifications are required when soliciting competitive bids (design– bid–build approach). – Change order to existing contract typically uses supplemental design plan sheets and specifications to detail the work. – Job-order contracting typically uses standard design details and specifications that were used to preestablish unit pricing. – Soliciting quotes typically uses standard design details and specifications. This informa- tion may be developed in house or may be taken from design plans from previous RSRR projects. Figure 7 provides a flowchart of the design decision process. It is important to note that by their nature, emergency PDR and FDR do not allow time for the preparation of design doc- uments or details. Standard details or standard operating procedures are typically used and should be developed in advance. If required, a construction safety and phasing plan (CSPP), along with FAA Form 7460-1, should be submitted to FAA. Airport Delivery Approach Hartsfield–Jackson Atlanta International Airport Design–bid–build Los Angeles International Airport Design–bid–build and competitive bids Louisville Muhammad Ali International Airport Design–bid–build McCarran International Airport Airport maintenance crew and change order to existing contracts Phoenix Sky Harbor International Airport Airport maintenance crew for PDR and on-call contractor for other jobs Raleigh–Durham International Airport Design and Construction Manager at-Riska Seattle–Tacoma International Airport Design–bid–build with change order to existing contract Vancouver International Airport Design–bid–build and construction managera aLarge-scale RSRR projects. Table 8. Delivery approach.

18 Rapid Slab Repair and Replacement of Airfield Concrete Pavement Source: Nichols Consulting Engineers, Chtd. Figure 7. Project design flowchart for rapid slab repair and replacement.