BFRL Strategic Goal

Measurement Science for Sustainable Infrastructure Materials

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A model concrete mixture, using real-shaped aggregates, being sheared computationally. The aggregate shapes were taken from x-ray computed tomography, reconstructed using spherical harmonic mathematical techniques, and incorporated into the DPD codes. What is the Problem?  National and international economic growth cannot continue into the next century unless industries, especially high volume trades like the construction industry, dramatically reduce the amounts of natural resources and energy they consume and the waste that they produce. To remain globally competitive while embracing sustainability, the U.S. construction industry needs to reexamine and redefine its practices: chemicals, materials, manufacturing methods, products, and waste disposal. Currently, construction materials, mainly concrete, steel, and polymeric materials, are being consumed at an annual rate of approximately $600 billion per year in new construction, and an additional $1.6 trillion in materials and construction products are required for renewal of the existing deteriorating U.S. physical infrastructure, according to the 2005 American Society of Civil Engineers Infrastructure Report Card. Sustainability drivers include energy costs, global climate change, environmental regulations, disposal costs, resource scarcities, and population increases. Examples of environmental concerns include the need to reduce environmental impact through the inclusion of increased fractions of supplementary cementitious materials, like flyash (one of the residues generated in the combustion of coal) and slag (a byproduct of metal smelting), into concrete as well as reduce environmental, health, and safety concerns related to the potential release of nanoparticles from nanocomposite materials that are rapidly being introduced into the marketplace. Sustainability decision analysis tools are currently being developed by industry, government agencies, and standards organizations. The efficacy of these decision tools, however, is greatly hampered by the lack of reliable sustainability input data, especially service life data for materials, components and systems, and the absence of measurement science for gauging this critical input. Without technically sound, thoroughly evaluated measurement science and data, the input available for making sustainability decisions is too crude and unreliable. This deficiency was highlighted at a recent meeting hosted by the U.S. Department of Commerce where industry expressed the “need for the establishment of internationally comparable metrics to measure the cost-effectiveness of sustainable manufacturing practices.” Why is it hard to Solve?  The most fundamental quality in full-life cycle assessment is a reliable estimate of the expected service life of a material, component, or system. Current durability tests were designed early in the 20th century to make qualitative performance assessments (i.e., at best, they can provide assessments as to whether product A is better than product B or vice versa under a specified set of exposure conditions) and these tests are fraught with scientific uncertainties. Extensive research efforts are being made to put service life estimation on a scientific basis. The measurement science needed to generate quantitative and accurate predictions of service life, however, is at a nascent level. The measurement science for predicting the service life of construction materials involves measurements of the degradation, flammability, and nanoparticle release from these materials. These processes are inherently complex. They involve numerous component interactions and multifunctional (chemical, physical, and mechanical) responses that operate over extremely wide length and time scale ranges. Nanoscale materials also possess unique properties (high surface area, high surface reactivity, large inter-particle forces) that will affect degradation, flammability, and the release rate of nanoparticles in unknown ways. Science-based models for predicting these complex phenomena  are just beginning to be developed, but such modeling is known to involve multiscale, multifunctional interactions in which damage accumulates over time. A multiplicity of linked models will be necessary to span these length and time scales, which in turn require advanced, high resolution measurement tools for characterizing the constituent properties of nano-infrastructural materials (NIMs). Why BFRL?  BFRL is the primary federal laboratory serving the building and fire safety industries. BFRL’s research in sustainability decision analysis tools and in high performance construction and building materials has been ongoing for several decades, and is internationally recognized. Industrial customers continue to recognize BFRL’s world class expertise in advancing the measurement science of infrastructure materials. This recognition is evidenced by their willingness over the last two decades to establish and support ongoing NIST/industry consortia, which have as their objectives creating and validating the measurement science necessary to effect reliable sustainability decisions for infrastructure materials. Component Programs: Service Life Prediction (SLP) of Nanostructured Polymeric Materials HYPERCON:  Prediction and Optimization of Concrete Performance Reduced Flammability of Materials  Contact: Jonathan Martin 301-975-6717 jonathan.martin@nist.gov