Nanotechnology in building_and_construction_sampling_2
Nanotechnology inBuilding and ConstructionDr. Joannie W. Chin
30,000 ft view30,000 ft viewWhynanotechnologyin building andconstruction?Technical barriersOPPORTUNITIESEmergingnanotechologiesin building andconstruction
Nanostructured Materials• Gaining control ofmaterials at thenanoscale bringsdifferent laws of physicsinto play.• Traditional materialsshow radically enhancedproperties whenengineered at thenanoscale.
Material Needs inBuilding and Construction• Deterioration of the nation’sinfrastructure:– Cost of repairs is estimated toexceed $2 trillion (NRC,ASCE).– Housing is plagued with poormaterial quality and excessivefire losses thathave led topremature failure and annual repaircosts exceeding $60 billion.
“The construction industry was the only industry toidentify nanotechnology as a promising emergingtechnology in the UK Delphi Survey in the early 1990s…However, construction has lagged behind otherindustrial sectors, such as automotive, chemicals,electronics and biotech sectors, where nanotechnologyR&D has attracted significant interest and investmentfrom large industrial corporations and venturecapitalists.”“Application of Nanotechnology in Construction”, Materials andStructures, 37, 649 (2004).
• Strong industry interest in use ofnanostructured materials to improveservice life and flammability performanceof building materials• Lack of measurement science capability topredict service life and flammabilityperformance of nanostructured materials.• Measurement science research is critical toenable U.S. construction industry toinnovate and respond to global competitionand new environmental regulationsNanomaterials in Construction
Cement and Concrete• Nano silica and clinker used toincrease densification and hencemechanical properties anddurability of cementitiousmaterials.• Service life can be doubledthrough the use of nano-additiveviscosity enhancers which reducediffusion of harmful agents inconcrete (patent pending).• Photocatalytic TiO2 added toconcrete to reduce carbon
Carbon Nanotubes• Heralded as one of the “Top ten advancesin materials science” over the last 50years, Materials Today, 2008.• Sales of carbon nanotubes projected toexceed $2B, >103metric tons annually inthe next 4 - 7 years.• Major use – electronics and composites.• Enhanced strength, stiffnessand toughness withoutadded weight• Improved durability• Increased functionality• Reduced flammability
Photovoltaics• Predominant photovoltaicmaterial is silicon, but anemerging technology involvesthe use of dye-sensitized nano-TiO2.• Large surface area of nanoTiO2 greatly increasesphotovoltaic efficiency.• Also has potential for lowermaterial and processing costsrelative to conventional solarcells.
Nanoadditive Fire Retardants• Use of nanoadditive fire retardantsprompted by bans on halogenatedflame retardants enacted in manystates.• Polymer nanocomposites filled withclay, CNTs, etc., possess improvedflammability resistance whilemaintaining or improving mechanicalproperties.• Reduces heat release rate during fireevent by formation of surface charwhich insulates underlying material.Poor Dispersion Good DispersionHeat Flux Heat Flux
Challenges• Techniques for dispersing nanofillers ANDmeasuring degree of dispersion.• Measurement of adhesion and interfacialproperties.• Chemical and mechanical measurements atthe nanoscale.• Prediction of nanocomposite properties andservice 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@example.com• Functionalized carbon nanotubes fornanocomposites and chemical probes –Tinh Nguyen, tinh.nguyen@Nist.gov• Nano fire retardants – Jeff Gilman,jeffrey.gilman@Nist.gov• General inquiries – Joannie Chin,firstname.lastname@example.org, 301 975 6815