1. HEAVYWEIGHT CONCRETE
Definition: Concrete in which heavy aggregate such as magnetic and iron
are used to increase the density of the concrete and protection against
radiation.
COMPOSITION
For producing heavyweight concrete, heavy natural aggregates such as
barites or magnetite or manufactured aggregates such as iron or lead shot
are used
The density achieved will depend on the type of aggregate used.
Typically using barites the density will be in the region of 3,500kg/m3,
which is 45% greater than that of normal concrete, while with magnetite
the density will be 3,900kg/m3, or 60% greater than normal concrete.
Very heavy concretes can be achieved with iron or lead shot as aggregate, is
5,900kg/m3 and 8,900kg/m3 respectively.
2. •High density or heavyweight concrete is concrete with a density
greater than 2600kg/m3.
•Its primary use is in radiation shielding, either in nuclear power
plants or in radiation therapy units.
•It can also be used as ballast in offshore locations such as
pipelines.
•High density concrete can be made from natural heavyweight
aggregates such as barites or magnetite which typically give
densities of 3500kg/m3 and 3900kg/m3respectively.
•They can also be made using iron or lead as a replacement for a
portion of the aggregate. These give even greater densities of
5900kg/m3 for iron or 8900kg/m3 for lead.
3. PROPERTIES OF HEAVYWEIGHT CONCRETE
•Heavyweight concrete can be pumped or placed by chutes over short
distances only, because of the tendency of coarse aggregate to segregate.
•Strenght is, however, of principal concern in the design of heavyweight
concrete mixtures suitable for use in prestressed concrete reactor vessels
(PCRV).
• The ideal property of normal and high density concrete are high modulus of
elasticity , low thermal expansion , and creep deformation
•Because of high density of concrete there will be tendency for segregation. To
avoid this pre placed aggregate method of concreting is adopted.
•The high density. Concrete is used in construction of radiation shields. They
are effective and economic construction material for permanent shielding
purpose.
•Most of the aggregate specific gravity is more than 3.5
4. USES OF HEAVYWEIGHT CONCRETE
1. They are mainly used in the construction of radiation shields
(medical or nuclear power plants).
2. Offshore, heavyweight concrete is used for ballasting for pipelines
and similar structures
3. It is also used for bridge counter-weight and for weighting down
underwater pipelines
•Increased density up to 4.0t/m3
•Reduced risk for thermal cracking
•Space savings
•Cost reduction
•Faster project completion
ADVANTAGES
5. •Fibre-reinforced concrete (FRC) is concrete containing
fibrous material which increases its structural integrity.
•It contains short discrete fibres that are uniformly
distributed and randomly oriented.
•Fibers include steel fibres, glass fibres, synthetic
fibres and natural fibres – each of which lend varying
properties to the concrete.
•In addition, the character of fibre reinforced concrete
changes with varying concretes, fibre materials,
geometries, distribution, orientation, and densities
FIBRE REINFORCED CONCRETE
6. There is an extensive use of fibre reinforced concrete due to their
light weight, low cost and sustainability
•Fibre reinforced concrete (FRC) is a concrete in which small
and discontinuous fibers are dispersed uniformly.
• Fibre reinforcement is one of the effective ways of improving
the properties of concrete
•Addition of Fibers to concrete makes it a Homogeneous and
Isotropic material.
• The Fibers used in FRC may be of different materials like
Steel, G.I., Carbon, Glass, Asbestos, Polypropylene, Jute etc
7. TYPES OF FIBRE
There are four types of fibres which we are using :-
1. STEEL FIBRE
2. GLASS FIBRE
3. NATURAL FIBRE
Steel fibre Glass fibre
8. Natural Fibres present cheap and sustainable alternative to the metallic
and synthetic Fibres used as building materials.
Their use, as a construction material, for improving the properties of
the composites costs a very little when compared to the total cost of the
composites.
Natural Fibres can be used in low-cost concrete structuresas
Reinforcement materials, especially in tropicalearthquake regions.
NATURAL FIBRE:-
9. NATURAL FIBRE:-
Natural Fibres present cheap and sustainable alternative to the
metallic and synthetic Fibres used as building materials.
Their use, as a construction material, for improving the
properties of the composites costs a very little when compared
to the total cost of the composites.
Natural Fibres can be used in low-cost concrete structures as
reinforcement materials, especially in tropical earthquake
regions.
10. •Polymer concrete is part of group of concretes that use polymers to
supplement or replace cement as a binder.
•The types include polymer-impregnated concrete, polymer concrete, and
polymer-Portland-cement concrete.
POLYMER CONCRETE
11. 1. Polymer concrete (PC), when the binder is a
polymer that replaces the cement paste
2. Polymer modified concrete (PMC), when the polymer is
mixed along with cement
3. Polymer impregnated concrete (PIC), when the cement
concrete is treated by soaking and polymerization.
4. Partially Impregnated And Surface coated polymer
concrete.
The composites using polymer can be:
12. Rapid curing at ambient temperatures
Good long-term durability with respect to freeze and
thaw cycles
Low permeability to water and aggressive solutions
Good resistance against corrosion
DISADVANTAGES
•It tends to be brittle in nature i.e. if fiber reinforcement is not
provided in some polymer concrete cases they tend to develop
cracks.
•High cost.
ADVANTAGES
