Nanotechnology in Building and Construction

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Nanotechnology in Building and Construction

• Dr. Joannie W. Chin

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30,000 ft view
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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.

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Material Needs in Building and
Construction

• Deterioration of the nations 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.

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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 RD has attracted
significant interest and investment from large
industrial corporations and venture
capitalists.   Application of Nanotechnology in
Construction, Materials and Structures, 37, 649
(2004).
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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

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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.

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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, gt103 metric tons annually in the
  next 4 - 7 years.
• Major use electronics and composites.

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Carbon Nanotubes

• Probes for microscopy and chemical imaging

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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.

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Coatings - Inorganic
Self-cleaning glass Nano-TiO2 coated
glass
transparent TiO2
conventional glass
self-cleaning glass
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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.

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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
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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.

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Opportunities

• Concrete with 2x service life Dale Bentz,
  dale.bentz_at_nist.gov
• Functionalized carbon nanotubes for
  nanocomposites and chemical probes Tinh
  Nguyen, tinh.nguyen_at_Nist.gov
• Nano fire retardants Jeff Gilman,
  jeffrey.gilman_at_Nist.gov
• General inquiries Joannie Chin,
  joannie.chin_at_nist.gov, 301 975 6815