How we can modeling the reactive poweder concrete material in abaqus program.

Research over the past decades has yielded a new
classification of highly resilient concrete called
Reactive Powder Concrete (RPC), now labeled and
classified as Ultra High Performance Concrete
(UHPC). RPC is one of the latest advances in
concrete technology and it addresses the
shortcomings of many concretes today [16]. RPC
possess ultra high static and dynamic strength,
high fracture capacity, low shrinkage and excellent
durability under severe condition. The
microstructure of RPC is optimized by precise
gradation of all particles in the mix to yield
maximum compactness [21]. RPC has been shown
to exhibit significantly improved tensile strength,
both before and after cracking. This tensile strength
of RPC is achieved as a result of the interaction of
the randomly oriented steel fibers acting as
reinforcement on a micro level which prevents
cracks from forming. After cracking has occurred,
the steel fibers are capable of sustaining additional
tensile loads until the fibers are pulled from the
matrix and the section severs [15]. The basic
principles for the development of RPC were
explained by many researchers [13, 18]. These
principles can be listed as below:
 There is no coarse aggregate and maximum
aggregate size may be between 0.3 to 0.6 mm.
 Powder is carefully optimized to achieve very
high compactness.
 Using high cement content, low water to
cement ratio (less than 0.2).
 Silica fume or another suitable pozzolanic
material can be added to the mix.
 Superplasticizer is in need to get high flowable
concrete.
 Steel fibers are to be added to increase the
concrete ductility.
 Pressing during hardening may be helpful to
get rid of excess water and to increase the paste
density.
 Heat treatment during curing can improve the
chemical process and strength gain.

Reactive Powder Concrete (RPC) is a developing composite material that will allow the concrete industry to optimize material use, generate economic benefits, and build structures that are strong, durable, and sensitive to environment. A comparison of the physical, mechanical, and durability properties of RPC and HPC (High Performance Concrete) shows that RPC possesses better strength (both compressive and flexural) and lower permeability compared to HPC. This page reviews the available literature on RPC, and also presents the results of laboratory investigations comparing RPC with HPC. Specific benefits and potential applications of RPC have also been described.

High-Performance Concrete (HPC) is not just a simple mixture of cement, water, and aggregates. It contains mineral components and chemical admixtures having very specific characteristics, which give specific properties to the concrete. The development of HPC results from the materialization of a new science of concrete, a new science of admixtures and the use of advanced scientific equipments to monitor concrete microstructure.

HPC 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 page 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)1.

Reactive Powder Concrete (RPC) was developed in France in the early 1990s and the world’s first Reactive Powder Concrete structure, the Sherbrooke Bridge in Canada, was erected in July 1997. Reactive Powder Concrete (RPC) is an ultra high-strength and high ductility cementitious composite with advanced mechanical and physical properties. It consists of a special concrete where the microstructure is optimized by precise gradation of all particles in the mix to yield maximum density. It uses extensively the pozzolanic properties of highly refined silica fume and optimization of the Portland cement chemistry to produce the highest strength hydrates1.

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 France2. A field application of RPC was done on the Pedestrian/Bikeway Bridge in the city of Sherbrooke, Quebec, Canada3. RPC was nominated for the 1999 Nova Awards from the Construction Innovation Forum. RPC has been used successfully for isolation and containment of nuclear wastes in Europe due to its excellent impermeability4.

The requirements for HPC used for the nuclear waste containment structures of Indian Nuclear Power Plants are normal compressive strength, moderate E value, uniform density, good workability, and high durability5. There is a need to evaluate RPC regarding its strength and durability to suggest its use for nuclear waste containment structures in Indian context.

Composition of Reactive Powder Concrete

RPC is composed of very fine powders (cement, sand, quartz powder and silica fume), steel fibres (optional) and superplasticizer. The superplasticizer, used at its optimal dosage, decreases the water to cement ratio (w/c) while improving the workability of the concrete. A very dense matrix is achieved by optimizing the granular packing of the dry fine powders. This compactness gives RPC ultra-high strength and durability6. Reactive Powder Concretes have compressive strengths ranging from 200 MPa to 800 MPa.

Richard and Cheyrezy1 indicate the following principles for developing RPC:

Elimination of coarse aggregates for enhancement of homogeneity
Utilization of the pozzolanic properties of silica fume
Optimization of the granular mixture for the enhancement of compacted density
The optimal usage of superplasticizer to reduce w/c and improve workability
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 fibres to improve ductility
Table 1 lists salient properties of RPC, along with suggestions on how to achieve them. Table 2 describes the different ingredients of RPC and their selection parameters. The mixture design of RPC primarily involves the creation of a dense granular skeleton. Optimization of the granular mixture can be achieved either by the use of packing models7 or by particle size distribution software, such as LISA8 [developed by Elkem ASA Materials]. For RPC mixture design an experimental method has been preferred thus far. Table 3 presents various mixture proportions for RPC obtained from available literature.