BUILDING MATERIAL CEMENT , INTRODUCTION , TYPES , COMPOSITIONS

2.  A cement is a binder a substance that sets and hardness
independently and can bind other material together. It
mainly consists lime [ 60 to 65%] and silica[ 20 to 25%] to
give strength and aluminum[ 4 to 8%] for quick setting and
rest 2 to 16% are meant for hardness and color.
 Generally it is known as Portland cement or Artificial
cement because of resistance of the color of the stone of that
name. Natural cement is manufactured by burning and
crushing natural cement stones.
 When cement is mixed with fine sand and water cement
mortar is produced and when it is mixed with fine sand,
crushed stone aggregate and water is known as cement
concrete.

3.  Lime is always whitish and cement is grey.
 When Cement is mixed with water starts
setting in a day or two but lime takes quite a
long period before hardening.
 Lime eats away the iron whereas cement
protects the iron and other metallic fitting from
atmospheric action.
 Cement is several times stronger material
than lime but like lime cement can not be
used for white washing.

4.  Roman cement :It is one of the best varieties of natural
cement, also known as parker’s cement. The crushed London
clay is burnt at low temperature and then ground to fine
powder to produce roman cement. Its small quantity is mixed
with water and used immediately.
 Pozzolana cement: It is a volcanic clay, drives its name form
the place where it obtained Pozzuoli in Italy. It is mixed with
lime then it produces a sort hydraulic cement which is more
resistant to chemical reaction than ordinary Portland cement.
But its has small strength.
 Medina cement : It is manufactured from septaria obtained
from England. It resembles more or less Roman cement but
stronger than Roman cement.

5. It is known as normal setting cement or
ordinary cement.
Artificial cement is used almost
everywhere because It can be
manufactured in any desired color and in
very large quantity.

6. NAME OF
CONSTITUENT
TYPICAL
PERSENTAGE
LIMIT OF %
ALUMINIA OR CLAY 5% 3 TO 8%
SILICA 22% 17 TO 25%
LIME 62% 60 TO 67%
IRON OXIDE 3.0% 0.5 TO 6%
MAGNESIA 2% 0.1 TO 4%
SULPHER TRIOXIDE 1.0% 1 TO 3%
ALKALIES [ SODA AND
POTASH]
1% 0.2 TO 1%
CALCIUM SULPHATE [
GYPSUM]
4% 3 TO 5%

7.  WHITE AND COLORED CEMENT : The cement when made from coloring
oxide of iron, manganese, and chromium results into white cement. It is
used for terrazzo flooring, face plasters, traffic curbs airdrome marking and
other ornamental works.
 COLORED CEMENT: The cements of desired colors are produced by
immediately mixing pigment with ordinary cement. The chromium oxide
gives green color, Cobalt produce blue color, From oxide with different
proportion produce brown , red or yellow color, Addition of manganese
dioxide gives black or brown colored cement.
 QUICK SETTING CEMENT: It is produced by reducing the percentage of
gypsum and adding a small amount of aluminum sulphate during the
manufacture of cement. This cement starts setting with in 5 minutes after
adding water becomes hard with in 30 minutes.
 LOW-HEAT CEMENT: In mass concrete works like construction of dams,
heat produced due to hydration of cement will not get dispersed easily .
This may give rise to crack hence it is perusable to use low heat cement.

8.  POZZULAND CEMENT: It can be processed from shale, certain
type of clay and contains pozzulana material 10 to 30%. It releases
less heat during setting , imparts high degree of water. Its tensile
strength is high but compressive strength is low.
 EXPANDING CEMENT: This cement expands as its strength. This
property is achieved by adding expanding medium like sulpho
aluminates and a stabilizing agent to ordinary cement. In repair work
it is very useful
 HIGH ALUMINA CEMENT: It is manufactured by calculating a
mixture of lime and bauxite. It contains 35 to 45% aluminates. It is
very dark in color almost black powder. It is more resistant to
sulphate and acid attack. It develops almost full strength with in 24
hours of adding water.
 BLAST FURNASE SLAG CEMENT: In the manufacture of big
iron, slag comes out as a waste product by giving grinding slinkiness
of cement with about 60 to 65%of slag, then this cement is
produced. The properties of this cement are more or less same as
ordinary cement but it is cheap.

9.  ACID RESISTANT CEMENT: This cement is produced
by adding acid resistant aggregate such as quartz ,
sodium silicate as soluble glass.
 SUPHATE RESISTANT CEMENT: It is manufactured
by keeping the percentage of tricalcium aluminates
below 5% in ordinary cement. Rate of hardening of this
cement is slow and requires longer period for curing.
 FLY ASH BLENDED CEMENT: It is a by product in
thermal stations. The particles of fly ash are very
minute and then they fly in creating air pollution
problem. It is found that the best way to dispose . Fly
ash is to mix it with cement in controlled condition and
drive some of the benefactors effects.

10. MANISHA AGARWAL