While the session doesn’t have a direct international theme, the topics and insights are highly relevant to an international audience. Many regions worldwide are grappling with questions about the sustainability and cost-effectiveness of extended pavement life cycles, making this session valuable for global attendees. A longer life cycle has traditionally been known as a sustainable practice by delaying reconstruction and major rehabilitation. However, questions arise whether designs exceeding 40–60 years make economic and environmental sense. Factors such as the discount rate used in life cycle cost analysis, uncertainties in future community needs and planning, electrification and automation of truck traffic, climate data, and limitations of durability prediction tools affect the viability of longer-life pavement designs. This session will explore these issues through four presentations addressing various aspects of designing concrete pavements for extended life spans and the necessary considerations.
Learning Objectives:
(1) Identify the historical factors and construction practices that contributed to the longevity of early 20th-century residential concrete pavements in California;
(2) Recognize the opportunities for applying long-life solutions throughout the concrete pavement life cycle, including new construction, rehabilitation, and preservation;
(3) Understand how to quantify economic and environmental impacts and benefits associated with rigid pavement and concrete pavement overlay solutions, and identify design and specification provisions that could support achieving benefits and limiting impacts;
(4) Understand how to apply best practices in Life-Cycle Cost Analysis (LCCA) to accurately compare pavement alternatives by incorporating robust rehabilitation cycles and representative economic conditions to reveal the true value of long-life pavement solutions.
Really Long-life Pavements – A Look at 80 to 100 Year Old California Streets
Presented By: Nathan Forrest
Affiliation: CNCA
Description: We study historical concrete pavements in California, revealing similarities in materials and construction practices and bidding data among various streets. The study indicated these pavements reside in residential areas, where a dry, no-freeze climate has enhanced longevity. These pavements, constructed between 1924 and 1942, with little maintenance due to good design and material quality, suggest effective practices for long-lasting concrete streets.
Documenting Long-Life Concrete Pavements: Case Studies
Presented By: Kurt Smith
Affiliation: Applied Pavement Technology, Inc.
Description: Longevity is a hallmark of concrete pavements and with it brings a number of benefits to both owners and users of the roadway facility. This not only includes reduced costs, fewer traffic disruptions, and lower maintenance requirements, but also reduced environmental impacts. This presentation reviews an array of nationwide examples of long-life concrete pavements throughout the United States and then presents specific case studies highlighting concrete pavement longevity achieved as part of new pavement construction, through rehabilitation with concrete overlays, and through preservation with concrete restoration treatments.
Improving Resilience and Sustainability through Rigid Pavements: LCCA and LCA Case Studies
Presented By: Matthew Sheffield
Affiliation: Sandhills Community College
Description: Pavements must be designed and constructed to withstand traffic loads and environmental conditions. However, climate change and extreme weather events pose a growing threat to pavement networks, with impacts differing by location due to variations in pavement design, construction quality, and environmental exposure. In this work, several different design options for rigid and flexible pavement sections predicted to provide equivalent performance over the desired service life were developed using mechanistic-empirical pavement design methods and the North Carolina pavement design procedure. The results of life cycle cost analysis (LCCA) and life cycle assessment (LCA) performed on these equivalent sections provided insight into trade-offs associated with these options, supporting sustainability and resilience objectives.
Unrealized Value: How Poor Life-Cycle Cost Analysis Practices Undervalue Long-Life Pavement Alternatives
Presented By: James Mack
Affiliation:
Description: Life-Cycle Cost Analysis (LCCA) is an economic tool that compares alternative pavement designs over their full-service lives considering initial construction costs, future rehabilitation costs and sometimes user costs. When properly executed, LCCA identifies which alternate has the lowest total cost of ownership. For the analysis to be credible, it must follow best practices in structured process, the engineering must be tailored to the designs under review, and economic assumptions must reflect real-world conditions and agency-specific costs. However, most current pavement LCCA practices fall short, particularly in their economic methodologies because they fail to accurately represent future agency costs or current market conditions, leading to a systematic undervaluation of long-life pavement solutions. This paper examines these deficiencies in standard LCCA approaches and demonstrates how correcting these assumptions can reveal the true long-term benefits of durable pavement strategies.
Enhancing Concrete Pavements Sustainability by Lengthening the Design Life
Presented By: Somayeh Nassiri
Affiliation: University of California Davis
Description: Concrete pavements are typically designed for a 40-year life by transportation agencies. While this is already a long-life design, there is the question that it may not result in the minimum possible life-cycle cost and environmental impacts. This study includes a collection of recommendations for the materials, design, and construction of concrete pavements aimed at extending the design life to up to 100 years. However, uncertainties remain in traffic load and climate predictions and the limitations of current durability and structural design models, all of which complicate efforts to accurately predict pavement life beyond the current 40-year standard. This study includes the pavement structural design, life-cycle cost analysis (LCCA), and the environmental life-cycle assessment (LCA) of three case studies, each one designed for 40, 60, and 100-year life and examines the impacts of the design life from environmental and economic aspects.