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Nanotechnology in Building and Construction. Dr. Joannie W. Chin. Why nanotechnology in building and construction?. Emerging nanotechologies in building and construction. Technical barriers. OPPORTUNITIES. 30,000 ft view. Nanostructured Materials.
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Nanotechnology in Building and Construction Dr. Joannie W. Chin
Why nanotechnology in building and construction? Emerging nanotechologies in building and construction Technical barriers OPPORTUNITIES 30,000 ft view
Nanostructured Materials • Gaining control of materials at the nanoscale brings different laws of physics into play. • Traditional materials show radically enhanced properties when engineered at the nanoscale.
Material Needs in Building and Construction • Deterioration of the nation’s infrastructure: • Cost of repairs is estimated to exceed $2 trillion (NRC, ASCE). • Housing is plagued with poor material quality and excessive fire losses that have led to premature failure and annual repair costs exceeding $60 billion. • Nanotechnology offers tremendous potential for improving building materials.
“The construction industry was the only industry to identify nanotechnology as a promising emerging technology in the UK Delphi Survey in the early 1990s… However, construction has lagged behind other industrial sectors, such as automotive, chemicals, electronics and biotech sectors, where nanotechnology R&D has attracted significant interest and investment from large industrial corporations and venture capitalists.” “Application of Nanotechnology in Construction”, Materials and Structures, 37, 649 (2004).
Nanomaterials in Construction • Strong industry interest in use of nanostructured materials to improve service life and flammability performance of building materials • Lack of measurement science capability to predict service life and flammability performance of nanostructured materials. • Measurement science research is critical to enable U.S. construction industry to innovate and respond to global competition and new environmental regulations
Cement and Concrete • Nano silica and clinker used to increase densification and hence mechanical properties and durability of cementitious materials. • Service life can be doubled through the use of nano-additive viscosity enhancers which reduce diffusion of harmful agents in concrete (patent pending). • Photocatalytic TiO2 added to concrete to reduce carbon monoxide and NOx emissions on roadways.
Enhanced strength, stiffness and toughness without added weight • Improved durability • Increased functionality • Reduced flammability Carbon Nanotubes • Heralded as one of the “Top ten advances in materials science” over the last 50 years, Materials Today, 2008. • Sales of carbon nanotubes projected to • exceed $2B, >103 metric tons annually in the next 4 - 7 years. • Major use – electronics and composites.
Carbon Nanotubes • Probes for microscopy and chemical imaging
Coatings - Organic • Projected to make up 73 % of nanocomposites market by 2010 (Freedonia Group). • Thin film, clear nanocomposites for improved scratch and mar properties. • Antimicrobial, self-cleaning surfaces. • Smart coatings: Sense pressure, impact, damage, chemicals, heat, light, etc.
Coatings - Inorganic Self-cleaning glass Nano-TiO2 coated glass transparent TiO2 conventional glass self-cleaning glass
Photovoltaics • Predominant photovoltaic material is silicon, but an emerging technology involves the use of dye-sensitized nano-TiO2. • Large surface area of nano TiO2 greatly increases photovoltaic efficiency. • Also has potential for lower material and processing costs relative to conventional solar cells.
Nanoadditive Fire Retardants • Use of nanoadditive fire retardants prompted by bans on halogenated flame retardants enacted in many states. • Polymer nanocomposites filled with clay, CNTs, etc., possess improved flammability resistance while maintaining or improving mechanical properties. • Reduces heat release rate during fire event by formation of surface char which insulates underlying material. Heat Flux Heat Flux Poor Dispersion Good Dispersion
Challenges • Techniques for dispersing nanofillers AND measuring degree of dispersion. • Measurement of adhesion and interfacial properties. • Chemical and mechanical measurements at the nanoscale. • Prediction of nanocomposite properties and service life over a wide range of length scales. • Unknown health and environmental effects – virgin, released material.
Opportunities • Concrete with 2x service life – Dale Bentz, dale.bentz@nist.gov • Functionalized carbon nanotubes for nanocomposites and chemical probes – Tinh Nguyen, tinh.nguyen@Nist.gov • Nano fire retardants – Jeff Gilman, jeffrey.gilman@Nist.gov • General inquiries – Joannie Chin, joannie.chin@nist.gov, 301 975 6815