Service Life Assessment and Predictive Modeling for an Aging Critical Infrastructure Proceedings of a Workshop (2021) / Chapter Skim
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3 Highway Infrastructure
3 Highway Infrastructure
Pages 10-19
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From page 10... ...
In light of this high demand, lack of funding, and aging infrastructure, the American Society of Civil Engineers (ASCE) awarded the nation's roadway infrastructure a "D" in 2013.1 The ASCE noted that approximately $101 billion is wasted in time and fuel each year, and the Federal Highway Administration suggested that it would take an investment of approximately $170 billion per year to elevate this grade to an "A." Given the gap between this amount and the 2015 Fixing America's Surface Transportation Act2 funding, which designated only approximately $40 billion per year over 5 years to the improvement of national highways, it is imperative that better performance pavement structures are created at lower cost, Timm explained.
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From page 11... ...
Timm provided an overview of the evolution of pavement design, beginning with the emergence of pavement engineering as a subdiscipline of civil engineer ing in the 1950s. Numerous highways were built across the United States in the 1950s; the American Association of State Highway and Transportation Officials (AASHTO)
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From page 12... ...
He added that Auburn University has developed perpetual pavement design software called PerRoad. Timm explained that asphalt and concrete industries have also embraced green technologies and are becoming more sustainable by using recyclable products in the mix designs of their materials.
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Weyers noted that both the exposure environment and the population of a particular place influence how much deicing salt is applied to highways. The equation used for service life modeling has only four parameters (surface chloride concentration C0, diffusion coefficient Dc, reinforcement cover depth x, and chloride corrosion initiation concentration)
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From page 14... ...
. Weyers then showed the cover depth distributions and the surface chloride concentrations from his analysis, both of which were fairly normally distributed.
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From page 15... ...
Weyers con cluded by reiterating the following suggestions for evaluating bridge decks based on modeling performance via chloride-induced corrosion: • Look at the damage; • Use the surface chloride as a parameter by measuring the environment and conditions relative to the population and the maintenance philosophy (need 30 surface chloride concentrations) ; • Use the cover depths as an additional parameter (need 30 cover depths)
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BREAKTHROUGH IN SELF-HEALING DAMAGE-TOLERANT CONCRETE TECHNOLOGY FOR RESILIENT INFRASTRUCTURE Victor Li, University of Michigan Li provided an overview of the challenges associated with the current genera tion of infrastructure: resiliency, durability, and sustainability. He defined resiliency as the ability to recover quickly from a major event such as extreme loading, and he described durability as the ability to lengthen the service life and decrease the num ber of repairs needed on infrastructure while maintaining load-carrying capacity at all times.
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From page 17... ...
According to Li, ECC remains durable even in a corrosive environment because the corrosion is distributed in small amounts among its many microcracks.6 ECC's tight crack widths also allow for suppression of cover spalling even in the face of expanding corroded steel (see Figure 3.2)
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From page 18... ...
Discussion In response to a question from de la Garza, Li explained that self-healing is a chemical process. In addition to the low water/cement ratio and the large amount of unhydrated cement grains that allow continued hydration with water exposure, there are calcites (that likely form as a result of the dissolution of the carbon dioxide from the air in the water)
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From page 19... ...
Dianne Chong, Boeing (retired) , asked Li if he had created an economic model including both life cycle cost and maintenance cost.
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