Seminar Presentation PPT on Reactive Powder Concrete (Civil Engineering)

D.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 RPC  The concept of reactive powder concrete was first

developed by P. Richard and M. Cheyrezy in the early 1990s  The world’s 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

homogeneity  2. Utilization of the pozzolonic properties of silica fume  3. Optimization of the granular mixture for the enhancement of compacted density  4. The optimal usage of super plasticizer to reduce w/c and improve workability

….continue  Application 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 CEMENT STEEL FIBERS

SAND

RPC

SILICA FUME

WATER

CRUSHED QUARTZ

SUPER PLASTICIZER

…..continue cement Cement is binding material for production of primary hydrates. Its particle size ranges from 1µm to 100µm. 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 150µm to 600µm

…..continue Quartz powder Its particle size ranges from 5µm to 25µm. 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 0.1µm to 1µm

…..continue Steel 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.

…..continue Super 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 Components  Sand  Cement  Quartz powder  Silica fume  Steel fibers  Superplasticiser

Function parameters  Give strength to aggregate  Binding material  Maximum reactivity during heat-treating  Filling the voids  Improve ductility  Reduce water binding

Types of RPC  The RPC family includes two types of concrete,

designated RPC 200 and RPC 800.  RPC 200 has compressive strength of 200 MPa  RPC 800 has compressive strength of 800 MPa

TYPICAL COMPOSITION OF RPC 200  Portland cement-type V  Fine Sand (150-400 micron)  Silica fume (18m2/gram)  Precipitated silica(35 m2/g)

 Super plasticizer (polyacrylate)  Steel fibers  Total water

 Compressive strength(cylinder)  Flexural strength  Young’s modulus

955 kg/m3 1051 kg/m3 229 kg/m3 10 kg/m3 13 kg/m3 191 kg/m3 153 kg/m3 170-230 MPa 25-60 MPa 54-60 GPa

TYPICAL COMPOSITION OF RPC 800          

Portland cement-type V Fine Sand (150-400 micron) Ground Quartz (4 microns) Silica fume (18m2/gram) Super plasticizer (polyacrylate) Steel fibers Total water Compressive strength(cylinder) Flexural strength Young’s modulus

1000kg/m3 500kg/m3 390 kg/m3 230 kg/m3 18 kg/m3 630 kg/m3 180 kg/m3 490-680 MPa 45-102 MPa 65-75 GPa

PROPERTIES OF RPC  COMPRESSIVE STRENGTH  FLEXURAL STRENGTH  WATER ABSORPTION

 WATER PERMEABILITY  HOMOGENITY  COMPACTNESS  MICROSTRUCTURE  MATERIAL 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 Mpa  Compressive strength of RPC ranges from 200-800

MPa

http://www.theconcreteportal.com/reac_po w.html

FLEXURAL STRENGTH  Plain 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 Property

HPC (80 MPa)

RPC 200

80 MPa

200 MPa

Flexural strength

7 MPa

40 MPa

Modulus of Elasticity

40 GPa

60 GPa