Constructability and productivity analysis for long life pavement rehabilitation strategies (LLPRS)

A large portion of the highway system in the United States has exceeded its design life and is close to the end of its service life. This study presents the processes and results of a constructability and productivity analysis for the Caltrans Long Life Pavement Rehabilitation Strategies (LLPRS), focusing on optimizing the maximum production capability within a 55-hour weekend closure. Concrete and Asphalt Concrete Rehabilitations were explored in this research as the two main components of the rehabilitation program. The constructability analyses explored with the assistance of concrete and asphalt concrete paving contractors in California the effects of the following parameters: rehabilitation materials, design profile (203, 254, and 305 mm of slab for concrete; CSOL and Full Depth AC of different thickness for asphalt concrete), curing time for concrete or cooling time for asphalt concrete, number and capacity of construction resources, number of lanes to pave, type of construction scheduling, and alternative lane closure strategies. Prototype constructability analysis programs running on commercial spreadsheet software were developed to interactively link all factors involved in the rehabilitation processes. In addition, sensitivity analyses were conducted to find which parameters constrain the production capability of the rehabilitation. The constructability analyses performed indicate that the proposed objective to rebuild 6 lane-kilometer of truck lanes within a 55-hour weekend closure has a low probability of success for both concrete and asphalt concrete rehabilitation. The analyses also show concrete curing time was not the most critical activity for the overall production of the concrete strategies. Material delivery resources, especially dump trucks for demolition and delivery trucks for concrete or asphalt concrete supply, were the major constraints limiting the production. Different rehabilitation working methods designed in relation to the construction access and lane closure tactics and pavement procedures also play an important role in determining the production capability of the rehabilitation. This study concludes that efficient lane closure tactics along with the right pavement profile can minimize non-working time such as cooling time waiting and increase the production capability of the project.