Nanotechnology in Building and ConstructionDr. Joannie W. Chin

30,000 ft view

Nanostructured MaterialsGaining 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 ConstructionDeterioration 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.

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.

Carbon Nanotubes

Probes for microscopy and chemical imaging

Coatings - OrganicProjected 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 - InorganicSelf-cleaning glass Nano-TiO2 coatedglasstransparent TiO2conventional glassself-cleaningglass

PhotovoltaicsPredominant 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 RetardantsUse 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 DispersionGood DispersionHeat FluxHeat Flux

ChallengesTechniques 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.

OpportunitiesConcrete 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