This document discusses metakaolin, which is produced by calcining kaolin clay between 650-800°C. It has pozzolanic properties and can partially replace cement in high strength concrete. Metakaolin increases the strength and durability of concrete by reacting with calcium hydroxide to produce additional calcium-silicate-hydrate gel. It improves the physical and chemical properties of concrete, leading to applications in infrastructure like bridges, dams, and buildings where high strength and durability are important.

1. PRESENTED BY:
E.Vishnu vardahan(14-143)
K.Ramakrishna Reddy(14-176)

2.  Introduction
 Manufacturing process
 Physical properties
 Chemical composition
 Advantages
 Applications
 Conclusion

3.  Meta +kaolin
 Metakaolin is an admixture used as an partial
replacement of cement in HSC(high strength concrete).
 A concrete is said to be high strength concrete if its
compressive strength is more than 40Mpa.
 Metakaolin is prepared by calcination of kaolin(clay
mineral) at an temperature of 650-800ºC .It has
pozzolanic properties.
 Chemical formula of Metakaolin is Al2O3·2SiO2·2H2O.
 It reacts with Ca(OH)2 one of the by-products of
hydration reaction of cement and results in additional
C-S-H gel which results in increased strength.

5.  Physical form-powder
 Fineness of metakaolin-700 to 900m2 /kg.
 Color of metakaolin – white/grey
 Specific gravity-2.50
 Specific surface-8 to15m2/g.

6.  Some of components
Chemical composition percentage (%)
Silica (SiO2) 54.3
Alumina (Al2O3) 38.3
Ferric oxide (Fe2O3) 4.28
Calcium oxide (CaO) 0.39
Magnesium oxide (MgO) 0.08
Sodium oxide (Na2O) 0.12
Potassium oxide (K2O) 0.50

7.  When cement is partially replaced with Metakaolin,
it reacts with calcium hydroxide and results in
extra C-S-H gel. C-S-H gel is the sole cause for
strength development in cement and cement based
concrete
 Cement + Water = C-S-H gel + Ca (OH)2 Ca (OH)2
+ Metakaolin = C-S-H gel
 It reduces the size of pores in cement paste by
transforming finer particles into discontinous
pores.
 It increases compressive and flexural strength.
 It reduces efflorosence in concrete.

8.  Strength and durability of concrete increases.
 Accelerates initial setting time of concrete
 Compressive strength of concrete increases@20%
 Cross section of structure can be reduced safely
i.e. amount of concrete used can be reduced.
 Reduces shrinkage in concrete.
 Ecofriendly by reducing amount of co2 emission.
 Reduces heat of hydration leading to shrinkage and
crack control

9. • As it has various advantages it can be used in
constructions of:
 dams
Bridges
Water retaining structures
High rise buildings
Off shore structures
Mass concreting
Nuclear power stations

10.  Compressive strength of concrete increases
by 20%.
 Use of 15% metakaolin increases workability.
 Improves mechanical properties of concrete.
 uneconomical due to its high cost whereas it
is economical in the aspects of durability and
strength