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76 Conclusions and Further Research Highway agencies across the United States are increasingly looking to implement policies, procedures, and practices to maintain a high level of construction quality while ensuring public safety, reducing traffic delays, building sustainable and long-lasting pavements, and increasing project- and network-level cost savings, particularly as they pertain to the construction and rehabilitation of concrete pavements. Notwithstanding any limitations and potential challenges inherent in adopting and successfully implementing new technologies, agencies are embracing advances in materials, equipment, placement techniques, project delivery, project management, and public outreach, as well as procurement, payment, and coordination methods, to achieve this goal. Over the past few decades, many projects have been constructed under varying levels of traf- fic, with increased efficiencies and decreased disruption to traffic, using one or more of these technologies. The purpose of this synthesis is to compile, review, and document the practices, strategies, and advancements pertaining to construction and rehabilitation of concrete pave- ments under traffic. Three tasks were conducted for this synthesis: a literature review, an agency survey, and development of case examples. A literature review was conducted to document agency practices using a survey questionnaire that was distributed to highway transportation engineers across 52 transportation agencies (all 50 U.S. state highway agencies, the Illinois Tollway, and the District of Columbia Department of Transportation) using a web-based online survey tool with analytic capabilities. A total of 45 survey responses were received, which included responses from agencies that indicated they did not currently use, or rarely used, concrete pavements. Case examples illustrating a variety of projects with different situations and considerations were also developed. A key aspect of construction and rehabilitation of concrete pavements under traffic is man- aging the work zone, particularly as it pertains to MOT. Agencies have used a variety of tech- niques and tools to accommodate traffic while constructing concrete pavements. Over 80% of highway agencies used temporary pavements, driver advisory signs, and portable signs in the work zone areas. Other techniques included 24/7 pilot-car operations and staged (rolling) detours. Many agencies were conducting rehabilitation work during nighttime hours and during weekend windows to avoid traffic impacts. To increase construction efficiency, some agencies chose to permit specific activities, such as allowing a subcontractor to work within the same work zone as other contractors on either side of the roadway, allowing work on shoulders across the road from a lane closure to proceed at the same time as the lane closure operation, allowing multiple work zones for each construction activity, limiting the number of paved crossroad closures in a work zone area, and allowing multiple work zones for sawing C H A P T E R 5
Conclusions and Further Research 77 and patching. New FHWA EDC initiatives such as TIM Responder Training and Smarter Work Zones also helped with work zone management and safety. The materials and design used on a project affect project schedule, time for construction, and number of construction/haul vehicles, all of which can affect traffic. Ninety-three percent of agencies that responded to the survey used HES concrete for patching, while 45% of agencies used precast paving technologies. Other methods used to accelerate construction and expedite schedules of new concrete pavements or reconstruction with concrete pavements were chemi- cal or mechanical subgrade soil stabilization before subbase placement, modification of base and subbase materials, nonwoven geotextiles as interlayers, and designing concrete pavement systems with reduced numbers of layers. The biggest advancements in terms of construction and rehabilitation of concrete pavements under traffic have been paving equipment and placement techniques that help with accelerating construction, reducing clearance requirements, and allowing earlier opening to traffic. Seventy- three percent of agencies used stringless paving technology and early-age saw-cutting techniques. Sixty-four percent of agencies used maturity recording devices/sensors. Other options used by agencies were RCC, zero-clearance pavers, and 3D modeling of the roadway. As in the case of paving equipment, paving operations can also affect the extent and dura- tion of traffic impacts. Decisions on closures, detours, two-lane versus one-lane paving, and haul roads all play important roles in how quickly a project can be completed and in MOT plans. Seventy-two percent of agencies considered paving plan development by the contractor for agency approval. Sixty-three percent of agencies noted that they were likely to consider time and access requirements to identify the project paving goals, or to consider two-lane versus one-lane paving. Fifty percent of agencies would consider haul-road needs based on limitations placed on contractor paving plans. Proper management of a construction project is necessary to ensure that the project is pro- ceeding as planned so that it is completed on time and within budget while meeting agency needs for quality, safety, and traffic impacts. Eighty-two percent of agencies used general engineering consultants to help with project management. Agencies have also started using risk management tools and systems, GISs and data management tools, and e-Construction tools for managing projects. The mechanism of project delivery is another factor that has a bearing on construction projects in terms of how they are managed and executed. The majority of survey respondents reported that they used the conventional DBB project delivery method. However, DB and its variations, such as DBM and DBW, PPPs, and CM/GC, are increasingly being adopted by highway agencies as ways to speed decision-making processes and schedules for project completion, which in turn can affect the extent of traffic impacts. The contracting and procurement phase is an important part of expediting construction and achieving quality. Procurement practices can be tailored to balance agency goals for costs, proj- ect duration, quality, traffic impacts, and other factors. More than 70% of agencies used VE and constructability reviews. New methods such as A+B bidding, ATCs, and faster decision making through partnering were increasingly being used to shorten project durations and reduce traffic impacts. Various forms of incentives and disincentives are effective tools that can be used by an agency to accelerate construction and reduce delays and corresponding traffic impacts. Eighty-eight percent of agencies used liquidated damages for late completion of new construction or for late opening to traffic after nighttime rehabilitation, while 75% of agencies had incentive and
78 Construction and Rehabilitation of Concrete Pavements Under Traffic disincentive provisions for early completion of projects. Practices such as lane rentals and flex- ible notice-to-proceed dates were also becoming increasingly common. Project-related communications within an agency and between various stakeholders are crucial for smooth and timely execution of construction and rehabilitation of concrete pave- ments under traffic. All responding agencies conducted preconstruction conferences between the agency, contractor, local community representatives, law enforcement, and so forth. At least 85% conducted prepaving team meetings, periodic construction team meetings, and meetings within the highway agency design and construction staff during design and prior to construc- tion. Project coordination meetings with representatives of other projects in the vicinity, on ROW and utilities, with media/schools/businesses/emergency services, and with other transpor- tation infrastructure agencies were also common. An important aspect of construction and rehabilitation of concrete pavements under traffic is to communicate project impacts to the traveling public, local residents and businesses, and other affected parties and agencies. A well-planned and well-executed public outreach program can be an effective tool to help reduce the extent and severity of traffic impacts. Ninety-five percent of respondents used press releases or media alerts for public outreach, while 83% of respondents used social media (Facebook, Twitter, LinkedIn, etc.). Email lists and project websites were other common methods of communication. As in the case of public outreach, conveying timely information to motorists is critical for reducing traffic impacts while constructing and rehabilitating concrete pavements under traffic. Ninety-five percent of agencies used changeable message signs, and 78% of agencies used social media for this purpose. Community-based traffic and navigation applications such as Waze were beginning to be used for motorist information purposes. More than 90% of agencies considered expedited construction operations, reduced traffic delays, maintenance of safe traffic operations, and protection against premature concrete pave- ment failures as important or most important factors in modifying agency practices for con- structing or rehabilitating concrete pavements under traffic. Sixty-four percent of agencies considered potentially higher bid prices as an important factor in their reservations and concerns about modifying their standard practices for constructing or rehabilitating concrete pavements under traffic. Forty percent of agencies noted local con- struction contractor resistance, absence of established performance criteria/standards, perceived negative impacts on competition (i.e., reduced number of bidders, particularly among small contractors), and possible increases in disputes with contractors and litigation as important or most important factors. Further Research The literature search and review found little documentation by highway agencies since most projects are constructed and managed using plans and specifications without published reports or articles. Much of the background information included in this report is from a handful of references. Further research similar to that performed on U.S. Highway 18 and documented by Cable (2012) would be helpful. The research could include new construction and rehabilitation, with traffic in the adjacent lane and with full closures, constructed by highway agencies and contractors across the United States. The research could document unique attributes, strate- gies used, and lessons learned from each of these projects to develop a comprehensive set of recommendations for construction and rehabilitation of concrete pavements under traffic. The following are additional ideas for further research:
Conclusions and Further Research 79 â¢ Perform a costâbenefit economic analysis of various technologies, practices, materials, and equipment as pertained to construction and rehabilitation of concrete pavements under traf- fic and specifically additional costs incurred due to MOT considerations and benefits in terms of reduced delay times, user costs, and work zone crash rates. â¢ Develop long-lasting and crack-resistant rapid-setting concrete materials to perform full- depth repairs of concrete pavement during an overnight closure. â¢ Study the effect of changes in processes, equipment, materials, and schedules on reducing disruption to traffic and the associated impacts on construction quality. â¢ Develop performance specifications and quality management procedures specific to concrete pavement construction or rehabilitation under varying levels of traffic. â¢ Develop guidelines that incorporate risk assessment and management for agencies that are looking to modify their standard construction and rehabilitation practices to better incorpo- rate traffic impacts. â¢ Study tort liability issues pertaining to construction and rehabilitation of concrete pavements under traffic. â¢ Develop a database of projects that were constructed under traffic conditions and steps taken to minimize effects on traffic. The database would include highway type, functional class, traffic, design, materials, construction techniques, procurement techniques, incentives and disincentives awarded, construction quality measures, and so forth. â¢ Develop training materials based on successfully implemented concrete pavement construc- tion and rehabilitation projects under traffic. â¢ Develop guidelines and processes to standardize planning and design for construction and rehabilitation of concrete pavements under traffic. â¢ Develop and frequently update a catalog of construction technologies and ways to expedite construction since new time-saving construction technologies and processes are introduced regularly. The productivity associated with each of these technologies and processes would be tracked for use in deciding the best technologies and processes to be used on future projects. â¢ Develop guidelines to optimize scheduling of crew shifts to improve productivity without affecting quality.