Annamacharya Institute Of Technology And Sciences

A SEMINAR ON NANO CONCRETE CIVIL ENGINEERING PRESENTING BY M.V.SRAVAN KUMAR REDDY 12701A0147

CONTENTS• Introduction• What is Nano?• Why nanotechnology for concrete?• What is Nano concrete?• Nano materials• Results• scope• Advantages• Dis – Advantages• conclusion

INTRODUCTION• Nanotechnology is one of the most active

research areas which has wide applications in almost all the fields.

• As concrete is most usable material in construction industry it’s been required to improve its quality.

• Improving concrete properties by addition of Nano particles have shown significant improvement than conventional concrete.

What is Nano?

The word “Nano” comes from Greek and it means “very small”.•1nm=0.000000001m.•500000 smaller than a pen line.•50000 smaller than a hair.•100 smaller than the DNA molecule.

Nano scale:

Why nanotechnology for concrete?

• Improves the material’s bulk properties.• Ability to control or manipulate materials at the atomic scale.

NANOSCALE ATTACK ON ASR (ALKALI SILICATE REACTION)

• To obtain thinner final products and faster setting time.• Cost effectiveness.• Lowered levels of environmental contamination.

What is Nano concrete?

• A concrete made with Portland cement particles that are less than 500nm as a cementing agent.

• Currently cement particle sizes range from a few Nano-meters to a maximum of about100 micro meters.

NANO MATERIALSNano materials are defined as a set of substances where at least one dimension is less than approximately 100 nanometres. Nanomaterial's are of interest because at this scale unique optical, magnetic,electrical, and other properties emerge. These emergent properties have the potential for great impacts in electronics, medicine, and other fields.

Some of main Nano materials used in concrete:

•Carbon Nanotubes.•Nano-silica.•Polycarboxylates.

CARBON NANO TUBES

• Carbon nanotubes are molecular-scale tubes of graphitic carbon with outstanding properties.

• They can be several millimetres in length and can have one “layer” or wall (single walled nanotube) or more than one wall (multi walled nanotube).

SINGLE WALLED CARBON NANO TUBES

multi walled carbon Nano tubes

PROPERTIES

• CNT are also highly flexible.• Mechanically, CNT appear to be the strongest material.• The smaller diameters.• Stiffest and strongest fibers.

NANO SILICA• It Is the first Nano product that replaced the micro

silica.• Advancement made by the study of concrete at

Nano scale have proved Nano silica much better than silica used in conventional concrete.

Nano silica

PROPERTIES

• High compressive strengths concretes ( 15 MPa and 75 MPa at 1 day; 40 MPa and 90 MPa at 28 days and 48 MPa and 120 MPa at 120 days.)

• High workability with reduced water/cement ratio.

• Use of super plasticizing additives is unnecessary. • Fills up all the micro pores and micro spaces.• Cement saving upto 35-45%.

POLYCARBOXYLATES• Polycarboxylates or polymer based concrete admixtures are

High Range Water Reducing admixture (HRWR).• low dosage-reduce water as much as high dosage of

conventional admixtures.• Higher dosage-produce Self Compacting Concrete (SCC).• This admixture type is very suitable for underwater anti-

washout concrete.

POLYCARBOXYLATES

The Gartnerplatzbrucke, across Kassel river in Germany

The jubilee church in Rome

RESULTS• Resistance to compression - 40 to 90MPa in 1 day.

Resistance to compression from 70 a 100 MPa (or more) in 28 days.

• Produces high resistance even with low addition (1 to 1.5 % of the cements weight) and gives self compacting characteristics with higher proportions (2.5 %).

• Meets the norms of environmental protection.

• 70% less use of additives as traditional silica, super plasticizers or traditional fibres.

SCOPE

• If Portland cement can be formulated with nano-size cement particles, it will open up a large number of opportunities.

• The cement will not only be more economical than organic polymers but also will be fire resistant.

• A number of investigations have been carried out for developing smart concrete using carbon fibers.

• This will become a reality with nano-cement because nano-carbontubes are much more effective than carbon fibers. The thickness of the composite can be reduced to microns and hence flexible and smart cement composite can be manufactured.

ADVANTAGES OF NANO CONCRETE• Cessation of contamination caused by micro silica solid

particles.• Lower cost per building site.• Concrete with high initial and final compressive and tensile

strengths.• Concrete with good workability.• Cessation of super plasticizing utilization.• Cessation of silicosis risk.

Dis-Advantages of Nano concrete

• Availability of sources for producing Nano materials is less.• For producing Nano materials there are no such equipment’s

to grain the materials up to Nano size.• Usage of Nano materials in concrete is difficult to replace the

materials in concrete like cement.

CONCLUSION

• Well dispersed Nano particles increase the viscosity of the liquid phase, improves the segregation resistance and workability of the system.

• Accelerates the hydration.• Better bond between aggregates and cement paste.• Improves the toughness, shear, tensile strength

and flexural strength of concrete.

ANY QUESTIONS ?

THANK YOU