Nano Material in Concrete

Contents Introduction Need of Nano material usage in concrete Types of Nano material used Nano silica Nano tubes Tio2 Applications Advantages & disadvantages Laboratory results

Introduction Nano= 10-9 m about one billionth of a meter A strand of DNA is 2 nm wide A human hair is about 100,000 nm A sheet of paper is 100,000 nm

What is Nano concrete ?

Concrete made with Portland cement particle sizes that are less than 500 nm as cementing agent

When matter is controlled at the Nano scale, the

following fundamental properties can change mechanical thermal electrical magnetic chemical reactivity

Need/ Demand Concrete most widely used material Need for Desired properties such as mechanical properties Durability Strength Seepage Minimizing Cost Environmental concern and green building concept

Types of Nano material Used in concrete Most known and research material used so far Nano Silica Carbon Nano tubes Titanium oxide Ti02

Nano silica

Properties

1- Increase strength 2- Flexibility 3- workability 4- Durability 5- increases Viscosity of fluid phase6-Reacts with calcium hydroxide = CSH all mechanical properties are controlled by CSH which is Nano-structured material

7-hydration process

Carbon Nano-Tubes

Carbon Nano tubes can of two forms to be used in concrete a) Single walled carbon Nano tubes (SWCNT) b) Multi walled Carbon Nano tubes (MWCNT) CNT’s display theoretical strength which is 100 times more than that of steel while just only one sixth of the specific weight of steel

1) High stiffness CSH 2) Reduces porosity of the CSH phase resulting in crease in Young’s modulus 3) Flexural strength 4) Increase in compressive Strength and durability 5) Autogenous shrikage

Titanium oxide Doesn’t participate in the reaction Increases the hydration Improves compressive strength Flexural strength Enhance the abrasion resistance Self cleansing

Case study

SCM Designation Avg. particle size

Material form Replacement%

Class F fly ash FA ~25 μm Powder 21

Slag S <45 Powder 40

Silica fumes SF 0.15 Densified powder

7

Nano silica NS 22 Slurry with water

3

NC vermiculite NC1 45 Clay dispersed in water

3

Twenty-six batches of concrete with various amounts and types of SCMs, as described in Table , were prepared in the laboratory, and specimens were cast for tests.

Specimens were tested for compressive strength and permeability.

The microstructure of selected concretes with improved compressive strength and permeability were analyzed using an atomic force microscope and nanoindentation to determine the reason for the improvements.

Control Concrete Silica Fume Concrete Nano silica Concrete

Results The nanoindentation and roughness results indicated that The NS concrete had the overall lowest roughness values, and the SF concrete the overall highest roughness values. Lower roughness values correspond to a more uniform cement paste.

Control Concrete Silica Fume Concrete Nanosilica Concrete

According to the AFM images, the NS concrete has the most uniform microstructure, followed by the regular concrete, and the SF concrete has the least uniform microstructure.

(a) (b)

(c)

Advantages • Low maintenance • Reduces the thermal transfer rate • Increasing the sound absorption of acoustic

absorber• Increasing the reflectivity of glass • improve segregation resistance• fix micro cracking• corrosion-resistance• Low life-cycle cost

Disadvantages Require a lot of energy Price nanotubes might cause a lung problem The research is in it´s early stage yet

Applications Bridges pipe joining materials and techniques Lighter and stronger structural composites Reservoirs Waste water management Roads Nano-sensors

What is the world’s strongest material ?

Graphene100 times stronger than steel

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