nanotechnology in building_and_construction_sampling_2
TRANSCRIPT
Nanotechnology in Building and Construction
Dr. Joannie W. Chin
30,000 ft view30,000 ft view
Why nanotechnology in building and construction?
Technical barriers
OPPORTUNITIES
Emerging nanotechologies in building and construction
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).
• 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
Nanomaterials in Construction
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.
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.• Enhanced strength, stiffness
and toughness without added weight
• Improved durability• Increased functionality• Reduced flammability
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 TiO2conventional
glassself-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.
Poor Dispersion Good Dispersion
Heat Flux Heat Flux
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, [email protected]
• Functionalized carbon nanotubes for nanocomposites and chemical probes – Tinh Nguyen, [email protected]
• Nano fire retardants – Jeff Gilman, [email protected]
• General inquiries – Joannie Chin, [email protected], 301 975 6815