In the next several decades a significant percentage of the country s transportation communications environmental and power system infrastructures as well as public buildings and facilities will have to be renewed or replaced Next generation infrastructure will have to meet very high expectations in terms of durability constructability performance and life cycle cost One way of meeting future expectations will be through improved high performance materials but before new materials can be confidently deployed in the field a thorough and comprehensive understanding must be developed of their long term performance in a variety of applications and physical environments The National Science Foundation NSF has launched an initiative to promote the development of innovative short term laboratory or in situ tests for making accurate reliable predictions of the long term performance of materials and requested that the National Research Council NRC conduct a workshop as a reconnaissance level assessment of models and methods that are being used or potentially could be used to determine the long term performance of infrastructure materials and components