Nanotechnology of Concrete

Virginia Concrete Conference

March 2-3, 2017

Jeremy Betts

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Nanotechnology

World of the extremely small

How Small?

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Sobolev

2016

CSH Nano Structure

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Nano Characterization (tests)

Nano indentation

Nano Scratch

Ultrasonic Atomic Force Microscopy

X-ray diffraction (XRD)

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Nano Indentation

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Nano scratch

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Ultrasonic Atomic Force Microscopy

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XRD

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Making Nano Materials

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Making Nano Materials

Top Down Bottom Up

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Nano assembly

Biomemetics

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Advanced Fibers

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Superhydrophobic Concrete

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Superhydrophobic Concrete

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Superhydrophobic Concrete

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Self Monitoring Concrete (piezoresistive property)

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Current Application of Nanoparticles

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Nano-silica (nano-SiO2)

Properties

Accelerates hydration reactions

and dissolution of C3S

Accelerates pozzolanic effect of fly ash

Denser packing of hydration

products

Increases viscosity (thicker)

Reduced bleed water

Longer mixing required

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Nano-silica (nano-SiO2)

Properties

Decreases porosity

Improved compressive strengths

Improved Flexural Strengths

Increased abrasion resistance

ASR mitigation

Pozzolanic effect higher than that

of silica fume

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Nano-silica (nano-SiO2)

Where has it been used?

RMG (Rock matching Grout)

SCC

Cementitious pavement coating

Viscosity Modifier

Accelerator

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Nano-titanium dioxide (Nano-TiO2)

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Nano-titanium dioxide (Nano-TiO2)

Photocatalysis

Pollutants (and stains) are

destroyed through molecular

adsorption and oxidative reaction

processes

Ultimate products : CO2, H2O,

NO3-, SO42-, O2, Cl-, ...

Catalyst remains indefinitely

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Nano-titanium dioxide (Nano-TiO2)

Properties

Does not noticeably alter fresh

concrete properties (basic)

De- polluting

Self Cleaning

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Nano-titanium dioxide (Nano-TiO2)

Where has it been used?

All Types of Concrete

Stucco

Cementitious coatings

Monuments

Buildings

Roadways

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Carbon Nanotubes/Nanofibers

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Carbon Nanotubes/Nanofibers

Nanotubes (CNT)

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Nano Fibers (CNF)

Carbon Nanotubes/Nanofibers

Properties

Compressive and flexural strength

enhancement

Chemical resistance

Electromagnetic shielding

Self sensing capabilities

Abrasion resistance

Shrinkage reduction

Decreased permeability

Increases Viscosity

Dispersion agent recommended

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Carbon Nanotubes

Where has it been used?

Several concrete mix types

Bulidings

Road repair (approved by GDOT)

Further research needed

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Other Concrete Nanoparticles

Nano-calcium carbonate (Nano-

CaCO3)

Nano-clays

Electric arc furnace dust (Nano-

ZnFe2O4)

Nanoalumina (Nano Al2O3)

Nanoiron (Nano Fe2O3)

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Nano-composites

New generation chemical

admixtures

– PCP (polycarboxylate-based polymers )

– Controlled release

technology

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Environmental Effects and Safety of Nanomaterials

Used in Concrete

Safety Precautions

– Respiration

– Ingestion

Environmental Precautions

– Agglomeration

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Upcoming ACI Publication

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Questions?

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