REACTIVE POWDER CONCRETE

Presentation by:Alok Ranjan

Roll No. : 13CE01013

School of Infrastructure

Introduction

●Reactive Powder Concrete (RPC) is a developing composite material that will allow the concrete industry to optimize material use, and build structures that are strong, durable, and sensitive to environment.

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●RPC is better known for its ultra-high strength and durability.

● RPC possesses better strength (both compressive and flexural) and lower permeability compared to HPC.

●HPC has achieved the maximum compressive strength in its existing form of microstructure.

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●However, at such a level of strength, the coarse aggregate becomes the weakest link in concrete.

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●In order to increase the compressive strength of concrete even further, the only way is to remove the coarse aggregate. This philosophy has been employed in Reactive Powder Concrete (RPC).

●The concept of reactive powder concrete was first developed by P. Richard and M. Cheyrezy and RPC was first produced in the early 1990s by researchers at Bouygues’ laboratory in France.●

●A field application of RPC was done in canada and the world’s first Reactive Powder Concrete structure, the Sherbrooke Bridge in Canada, was erected in July 1997.●

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COMPOSITION OF REACTIVE POWDER CONCRETE

●RPC is composed of : ➢Sand(100 to 600mm diameter)➢Cement➢Quartz powder➢Silica fumes(25% of volume of concrete)➢Superplasticizer➢Steel fibres(upto 0.2mm dia. And 12mm length)

●Superplasticizers: It is used at its optimal dosage.➢Decreases the water to cement(w/c) ratio.➢Increases the workability of the concrete.➢

●Steel fibres: Improve ductility.●Sand:Provides strength.●Silica fumes:Filling the voids.●Cement:Binding material.●

●Quartz powder:Maximum reactivity during heat treating.It fills grade between sand and cement particles making the matrix denser.●The water to cement ratio used in RPC ranges from 0.15 to 0.25.●The material having the largest particle size in RPC is the sand.●A very dense matrix is achieved by optimizing the granular packing of the dry fine powders. This compactness gives RPC ultra-high strength and durability.

PROPERTIES OF RPC

1. COMPRESSIVE STRENGTH●Normal RPC provides compressive strength upto 200Mpa.●But by the optimum use of quartz sand ,steel agreegate and heat treatment ,a compressive strength of 600-800Mpa can be obtained.●The RPC family includes two types of concrete, designated as RPC 200 and RPC 800.

Comparison of RPC 200 and RPC 800

RPC 200 RPC 800

Pre-setting pressurization None 50Mpa

Heat treating 20 to 90°C 250 to 400°C

Compressive strength(using quartz sand)

170 to 230 MPa 490 to 680 MPa

Compressive strength(using steel agreegates)

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650 to 810 Mpa

Flexural strength 30 to 60 MPa 45-141 Mpa

2.FLEXURAL STRENGTH:●Due to the presence of steel fibres RPC possesses higher flexural strength.

●It may range from 30-141 Mpa.

3.Water Absorption:●The percentage of water absorption of RPC is very low .It is one of its property which encourages its use as a nuclear waste containment material.●The incorporation of fibres and the use of heat curing is seen to marginally increase the water absorption.

Water absorption of RPC and HPC

4.WATER PERMEABILITY:

5.RESISTANCE TO CHLORIDE ION PENETRATION

RPC (NC) RPC(HWC) RPC with fibres(NC)

RPC with fibres(HWC)

Cumulative Charge passed in Coulombs

4 94 140 400

ASTM C1202 classification

Negligible Negligible Very Low Very Low

●High chlorine ion penetration property of RPC makes it suitable for use in nuclear waste containment structures.

6. DURABILITY●Long life:●Abrasion wear : 2.5 times lower.●Water absorpton : 7 times lower.●Rate of Corrosion : 8 times lower.●Chlorine ion diffusibility : 25 times lower.●7.Compactness:Application of pressure before and Application of pressure before and during the setting period of concrete to obtain during the setting period of concrete to obtain maximum density.maximum density.

APPLICATIONS

1. RPC is light-weight material.So it can be used to decrease the overall dead load of the struture.

2. Containment of Nuclear wastes:➢ Used for isolation and containment of nuclear wastes➢It has been used for blocking & stabilization of containment waste.●Owing to its high durability, RPC can even replace steel in compression members.

LIMITATIONS

➢It is expensive as compared to high performance concretes.➢Least costly components of conventional concrete is basically replaced by expensive ones.➢RPC is still under developing phase .So,some of its long term properties are still not well-known.

CONCLUSION

●It has immense potential in construction due to its mechanical strength and durability aspects.

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●RPC has ultra dense microstructure giving advantages of water proofing and durability characteristics.

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