Reactive Powder Concrete

Reactive Powder ConcreteD.Siddhartha(UG101218) Introduction Reactive powder concrete (RPC) is ultra high strength and high ductile composite material with advanced mechanical properties.Reactive powder concrete is a concrete without coarse aggregate, but contains cement, silica fume, sand, quartz powder, super plasticizer and steel fiber with very low water binder ratio.Compressive strength of RPC ranges from 200 to 800 Mpa.How to get ultra strength???Conventional concrete has achieved the maximum compressive strength in its existing form of microstructure. However, at such a level of strength, the coarse aggregate becomes the weakest link in concrete. 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).

History of RPCThe concept of reactive powder concrete was first developed by P. Richard and M. Cheyrezy in the early 1990s The worlds first Reactive Powder Concrete structure, the Sherbrooke Bridge in Canada, was erected in July 1997.

Principles proposed by P. Richard and M. Cheyrezy 1. Elimination of coarse aggregates for enhancement of homogeneity2. Utilization of the pozzolonic properties of silica fume3. Optimization of the granular mixture for the enhancement of compacted density4. The optimal usage of super plasticizer to reduce w/c and improve workability .continueApplication of pressure (before and during setting) to improve compaction

Post-set heat-treatment for the enhancement of the microstructure

Addition of small-sized steel fibers to improve ductility

Composition of RPC..continuecement Cement is binding material for production of primary hydrates. Its particle size ranges from 1m to 100m. Optimum cement properties are C3S: 60% C2S: 22% C3A: 3.8% C4AF: 7.4%Sand Coarse aggregates are replaced by fine sand. It gives strength to the concrete. Size ranges from 150m to 600m

..continueQuartz powder Its particle size ranges from 5m to 25m. It must be in crystalline form.Silica fume Silica fume is used for filling voids and enhance rheology and for production of secondary hydrates. Its particle size ranges from 0.1m to 1m

..continueSteel fibres steel fibres are added to improve ductility. It should have good aspect ratio and should be able to improve ductility. Its length ranges from 13mm to 25mm. It should be straight.

..continueSuper plasticizer super plasticizer to reduce w/c and improve workability. A copolymer of acrylic ester (CAE), a polynaphtalene Sulfonate (PNS) and a polymelamine sulfonate (PMS) are normally employed for the purpose.

..continue

Components with function parameters ComponentsSand

CementQuartz powder

Silica fumeSteel fibersSuperplasticiser

Function parametersGive strength to aggregateBinding materialMaximum reactivity during heat-treatingFilling the voidsImprove ductilityReduce water binding

Types of RPCThe RPC family includes two types of concrete, designated RPC 200 and RPC 800.RPC 200 has compressive strength of 200 MPaRPC 800 has compressive strength of 800 MPaTYPICAL COMPOSITION OF RPC 200Portland cement-type VFine Sand (150-400 micron)Silica fume (18m2/gram)Precipitated silica(35 m2/g)Super plasticizer (polyacrylate)Steel fibersTotal waterCompressive strength(cylinder)Flexural strength Youngs modulus

955 kg/m31051 kg/m3229 kg/m310 kg/m313 kg/m3191 kg/m3153 kg/m3170-230 MPa25-60 MPa54-60 GPaTYPICAL COMPOSITION OF RPC 800Portland cement-type VFine Sand (150-400 micron)Ground Quartz (4 microns)Silica fume (18m2/gram)Super plasticizer (polyacrylate)Steel fibersTotal waterCompressive strength(cylinder)Flexural strength Youngs modulus

1000kg/m3500kg/m3390 kg/m3230 kg/m318 kg/m3630 kg/m3180 kg/m3490-680 MPa45-102 MPa65-75 GPa PROPERTIES OF RPCCOMPRESSIVE STRENGTH FLEXURAL STRENGTH WATER ABSORPTIONWATER PERMEABILITYHOMOGENITYCOMPACTNESSMICROSTRUCTUREMATERIAL DUCTILITY COMPRESSIVE STRENGTH Higher compressive strength than HPC

High performance concrete(HPC) is conventional concrete with high strength, high workability, high chemical resistance

Max Compressive strength of HPC: 75 MpaCompressive strength of RPC ranges from 200-800 MPa

http://www.theconcreteportal.com/reac_pow.html FLEXURAL STRENGTHPlain RPC is found to possess marginally higher flexural strength than HPC.

The increase of flexural strength of RPC with the addition of steel fibers is higher than that of HPC.

Flexural strength at first cracking is higher than ultimate flexural strength of normal concrete.Comparison of HPC (80 MPa) and RPC 200 PropertyHPC (80 MPa)RPC 200Compressive strength80 MPa200 MPaFlexural strength7 MPa40 MPaModulus of Elasticity40 GPa60 GPaFracture Toughness