Nanotechnology in building_and_construction_sampling_2

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, 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