Eul-Bum Lee

Calcool: A multi-layer Asphalt Pavement Cooling Tool for Temperature Prediction During Construction

The temperature at which compaction takes place is an important factor in the construction of asphalt concrete pavements. In cold climates, rapidly cooling mats can contribute to poor compaction. Under warm paving and high traffic demand conditions, time of construction is a greater concern, and the compaction schedule should minimize the required time for construction. This research created a computer tool (CalCool), based on theoretical heat transfer considerations, for use by pavement designers and on-site construction crews to predict the pavement temperature during construction and modify designs or compaction procedures accordingly. A model validation study compared CalCool to several construction scenarios. The comparisons were favorable in the single-layer cases, but increased discrepancies were observed Fin the multi-layer cases. Future validation studies are needed to expand the data set beyond the two sites examined in this paper.

CONSTRUCTION PRODUCTIVITY AND CONSTRAINTS FOR CONCRETE PAVEMENT REHABILITATION IN URBAN CORRIDORS

A constructability analysis tool was developed to help the California Department of Transportation (Caltrans) determine which rehabilitation and construction strategies were the most feasible in an urban environment to maximize production and minimize traffic delay. With the assistance of California concrete paving contractors, the constructability analysis explored the effects of the following parameters on the construction production of concrete pavement rehabilitation in California: pavement thickness, concrete material, curing time, number and capacity of resources, number of lanes to be paved, type of construction scheduling, and alternative lane closure strategies. The constructability analyses indicated that the proposed Caltrans strategy to rebuild 6 lane-km within a 55-h weekend closure period had a low probability of success. The analyses showed that the concrete curing time was not the most critical activity for the overall production. Material delivery resources, such as dump trucks for demolition and concrete delivery trucks, were the major constraints that limited production. An increase in the concrete slab thickness from 203 to 305 mm reduced the level of production by about 50 percent. A concurrent-construction working method was more productive than a sequential-construction working method. The number of lanes to be paved affected the production capability. Continuous closures were more productive and less inconvenient to the public than weekend-only closures.

Selection of Pavement for Highway Rehabilitation Based on Life-Cycle Cost Analysis: Validation of California Interstate 710 Project, Phase 1

Life-cycle cost analysis (LCCA) for highway projects is an analytical technique that uses economic principles to evaluate long-term alternative investment options, especially for comparing the value of alternative pavement structures and strategies. Recently, the California Department of Transportation (Caltrans) mandated LCCA implementation to evaluate the cost-effectiveness of pavement design alternatives for highway projects in the state. An LCCA approach was utilized for validation of the pavement design on the I-710 Long Beach rehabilitation project with three pavement types: innovative (long-life) asphalt concrete pavement (ACP), standard-life ACP, and long-life portland cement concrete pavement (PCCP). The LCCA followed the Caltrans procedure and incorporated information filed by the project team. The software tools Construction Analysis for Pavement Rehabilitation Strategies (CA4PRS) and RealCost were used for quantitative estimates of construction schedule, work zone user cost, and agency cost for initial and future maintenance and rehabilitation activities. Conclusions from the LCCA supported use of the innovative ACP alternative, the one actually implemented in the I-710 Long Beach project (Phase 1), since the innovative ACP alternative had the lowest life-cycle costs over the 60-year analysis period. For example, the life-cycle agency cost for the innovative ACP alternative (

Construction Productivity Analysis for Asphalt Concrete Pavement Rehabilitation in Urban Corridors

33.2 million) was about

Automated Work Zone Information System on Urban Freeway Rehabilitation: California Implementation

7.9 million more cost-effective than that of the standard-life ACP alternative (

Knowledge-Based Scheduling Analysis Software for Highway Rehabilitation and Reconstruction Projects

41.1 million) and about

Streamlined Strategies for Faster, Less Traffic-Disruptive Highway Rehabilitation in Urban Networks

17.2 million less expensive than the long-life PCCP alternative (

Multifaceted public outreach and cost-benefit analysis for its effectiveness validation

50.4 million). Utilization of the proposed computer tool–aided LCCA procedure would contribute substantial economic benefits to nationwide highway projects, especially rehabilitation and reconstruction.

Accelerated Pavement Rehabilitation and Reconstruction with Long-Life Asphalt Concrete on High-Traffic Urban Highways

The results of a constructibility and productivity analysis for the California Department of Transportation Long Life Asphalt Concrete Pavement Rehabilitation Strategies program are presented. With the assistance of California asphalt concrete (AC) paving contractors, the analysis explored the effects on construction productivity of rehabilitation materials, design strategy (crack seat and overlay, full-depth replacement), layer profiles, AC cooling time, resource constraints, and alternative lane closure tactics. Deterministic and stochastic analysis programs were developed. A sensitivity study that examined the construction production capability within a 55-h weekend closure was performed. Weekend closures were also compared with continuous closures. Demolition and AC delivery truck flows were the major constraints limiting the AC rehabilitation production capability. It was concluded from the study that efficient lane closure tactics designed to work with the pavement profile can minimize the nonworking time to increase the construction production efficiency. The results of the study will help road agencies evaluate rehabilitation strategies and tactics with the goal of balancing the maximization of production capability and minimization of traffic delay during urban pavement rehabilitation.

Value Analysis Using Performance Attributes Matrix for Highway Rehabilitation Projects: California Interstate 80 Sacramento Case

In October 2004, about 9 lane km of deteriorated truck lanes on Interstate 15 at Devore in Southern California was rebuilt during 18 days with extended one roadbed full-closures with the counterflow traffic system and 24-h construction operations. The project implemented the automated work zone information system (AWIS) to reduce peak hour delay during construction by changing road users travel patterns and diverting traffic to detour routes. This paper describes the design, performance, and validation of AWIS with monitored traffic data before and during construction used. The AWIS was installed to provide road users with real-time travel information so that they could avoid traffic delays in the construction work zone (CWZ) corridor. Travel times through the CWZ were estimated from speed data and enhanced in two ways: (a) portable and permanent changeable message signs on site and (b) off-site (project website) implementation with travel time messages, traffic snapshots, and video streaming. AWIS trave...