Non-Conventional Concrete Technologies

Submitted By:Abhishek Gupta11113002

Outline

oIntroductionoConventional vs Non conventional concreteoWhy Non conventional techniques are betteroSome Non Conventional Concrete TechnologiesoConclusion

Conventional Concrete

Conventional concrete is a conglomerate of hydraulic (Portland) cement , sand, stone, and water. It was developed approximately 150 years ago to imitate natural stone while providing less labor-intensive methods of shaping the material

Non-Conventional Concrete Technologies

Task specificEnvironment FriendlyCost effective

Self Compacting Concrete

oFirst developed in 1988oto achieve durable concrete structures.oFirst Practical use in Japan

DEVELOPMENT OF SELF-COMPACTING CONCRETE

durability of concrete structures in Japandurable concrete structures sufficient compaction skilled workersGradual reduction in skilled workers Requirement of new technology proposed by Okamura in 1986It is a ‘High performance Concrete’ due to its high durability

Important Properties & Benefits

Self-compactabilityAvoidance of bleeding and segregationLow shrinkageLow permeabilityStrength as neededSafer, quieter sitesBetter appearance

What is the secret?

Optimum Paste Viscosity and water content which is attained by one of three means:High cement contentHigh content of Fly Ash, Silica Fume etc.Use of Viscosity Modifying AdmixtureLow water content using HRWR High Strength

REQUIREMENTS OFCONSTITUENT MATERIALS

CEMENTTypical cement content – 350 to 450 kg/m3.Cement > 500kg/m3 →shrinkageCement < 300kg/m3 →Requires Extra fine fillers

AGGREGATEFine AggregateCoarse AggregateFly ash: In appropriate quantity may bethe added the quality

REQUIREMENTS OFCONSTITUENT MATERIALS

OtherSilica fumes: Added to improve the mechanical properties of scc.Stone powder: finely crushed lime stone,dolomite or granite added to increase the powder content.Fibres: fibres may be used to enhance the properties of scc as same as normal concrete

Measuring Flowability

1) Slump Flow Test (Simple)

2)Slump Flow Test (With J ring)

What are the difficulties

Higher cost – especially if high strength is not needed

Plant control has to be better

Why it Appears Better?

Segregation Resistance-Achieved by mortar viscosity, not aggregate grading

No Bleeding and perfect compaction

Uses

Can be used for heavily reinforced structures

Structures made using SCC

Green ConcreteoFirst invented in Denmark in the year 1998 Kyoto ProtocloloMade with concrete wastesoSustainable Construction

ADVANTAGES OF GREEN CONCRETE

Reduced CO 2 emissions.Low production costs.Saves energy, emissions and waste water.Helps in recycling industry wastes.Reduces the consumption of cement overall.

o Better workability.o Sustainable development.o Greater strength and durability than

normal concrete.o Compressive strength and Flexural

behavior is fairly equal to that of the conventional concrete.

SUITABILITY OF GREEN CONCRETE IN STRUCTURES

Improve damping resistance of building.

speed of construction, shorten overall construction period. Reduce the dead weight of a facade from 5 tons to about 3.5 tons.Good thermal and fire resistance, sound insulation than the traditional granite rock

Applications

LIMITATIONS

cost of reinforcement comparatively less lifeSplit tension of green concrete

High strength concrete

strength in excess of 60MPa ultra high performance concrete (UHPC) will more usually contain cement replacement materials and a high-range water-reducer (HRWR) or superplasticiser(SP

Ultra High Strength ConcreteIn what kind of structures ?

Conclusion

Concrete that is a little more expensive per cubic meter to buyBUTIt will require less skill and effort to placeIt will look better with no appearance defectsIt will be more durableIt will require more skill at the batching plant

References

o Journal of Advanced Concrete Technology Vol . 1 , No . 1 , 5 - 1 5

(Self Compacting Concrete)

o Edvardsen Ing. Carola and Tølløse Karsten (2001). Environmentally “Green” Concrete Structures

o Benjamin A. Graybeal, and Joseph L. Hartmann(2003). STRENGTH AND DURABILITY OF ULTRA-HIGH PERFORMANCE CONCRETE