seminar topic on high density concrete-

1. SEMINAR ON HIGH DENSITY
CONCRETE

2. INTRODUCTION
 Density of conventional concrete is in the order of about
2400kg/m3
 To call the concrete as high density concrete it must have
density of about 3360-3840kg/m3 (about 50% higher than
conventional concrete)
 What makes it to call high density concrete?
Normal concrete comprises of 70% aggregate(FA+CA), these
aggregates when replaced by ores of iron or other metal having
high density the resulting concrete is said to be high density
concrete.

3. DEFINITION
• Concrete in which heavy aggregate such as
magnetite and iron ore are used to increase
the density of the concrete and protection
against the radiation.

4. COMPOSITION
 For producing high density concrete it uses heavy natural
aggregates such as barites or magnetite or manufactured
aggregates such as iron or lead shot
 The density achieved will depend on type of aggregate used
typically using barites the density will be in the range of
3500kg/m³ (45% greater), while with magnetite the density
will be 3900kg/m³(60% greater).
 Very heavy concretes can be achieved with iron or lead shots
as aggregates having densities of about 5900kg/m³ and
8900kg/m³ respectively

5. MATERIAL AND MIX PROPORTION
 Except for the high density aggregates and some hydrous ores as
well as boron minerals, the same minerals and proportioning
methods are used for producing high density concrete mixtures as
are used for conventional normal weight concrete.
 For details pertaining to concrete-making metarials for biological
shielding, the standard specifications should be consulted: astm c
637 (specification for aggregates for radiation shielding concrete)
and astm c 638(nomenclature of constituents of aggregates for
radiation shielding concrete).

6. Predominant constituent Class of material Specific gravity
Serpentine Crushed stone, hydrous
silenite
2.4-2.65
Limonite Crushed stone, hydrous
iron ore
3.4-3.8
Goethite Crushed stone, hydrous
iron ore
3.5-4.5
Barite Gravel or crushed stone 4-4.4
Ilmenite Crushed stone, iron ore 4.2-4.8
Hametite Crushed stone, iron ore 4.6-5.2
Iron Manufactured from iron 6.5-7.5
The various types of heavy weight aggregate used for
making high density concrete with their predominant
constituent and specific gravity are listed in table
below

7. PROPERTIES OF HIGH DENSITY
CONCRETE
FRESH STATE
• Because of the high denstiy of aggregate particles, segregation
of fresh concrete is one of the principal concerns in mix
proportioning. From the standpoints of high unit weight and a
lower tendency for segregation, it is desirable that both fine
and coarse aggregate be produced from high-denstiy rocks and
minerals
• Due to the rough shape and texture of crushed aggregate
particles, high densityconcrete mixtures tend to be harsh. To
overcome this problem it is customary to use a finer sand, a
greater proportion of sand in aggregate than conventional
concrete, and cement contents higher than 360 kg/m³.

8. • High density concrete can be pumped or placed
by chutes over short distances only, because of
the tendency of coarse aggregate to segregate.

9. HARDENED STATE
•The ideal property of normal and high density concrete are high
modulus of elasticity , low thermal expansion , and creep
deformation.
•The other properties of High density concrete with different
types of high density aggregates are as shown in table below

11. ADVANTAGES OF HIGH DENSITY
CONCRETE
As radiation shield:
Concrete is an excellent shielding material that possesses the
needed characteristics for radiation and has satisfactory
mechanical properties and has a relatively low maintenance
cost. Also, the ease of construction makes concrete more
suitable. Its only disadvantage is space and weight.
The effectiveness of radiation shielding quality of concrete can
be increased by increasing the density. Another important
requirement of shielding concrete is its structural strength even
at high temperature. To produce high density and high strength
concrete, it is necessary to control the water cement ratio very
strictly.

12. KUDANKULAN NUCLEAR POWER PROJECT- USED
HD CONCRETE AS A RADIATION SHIELD

14. It is also used for bridge counter-weight and
for weighing down underwater pipelines
It provides twice the density in half the space
to solve today's demanding space constraints.
High density concrete offers more strength.
It is resistant to extreme weather.

15. DISADVANTAGES OF HIGH DENSITY
CONCRETE
It affects the initial setting time.
Due to the high density of aggregates,
segregation of concrete is possible if no
proper care is taken.
It is not cost effective, as the initial cost is
comparatively high.

16. REFERENCES
• Concrete technology by M S Shetty-Special
concrete and concreting methods.
• M.Santhanam & R.Geetu (November 2010)
had investigated that “Mechanical Properties
of high Density Concrete used in Fast reactors
for Structural and Shielding purposes” for Civil
Engineering Division, IGCAR, kalpakkam.
• Light weight and heavy weight concrete by
Semedar salim- www.slideshare.net