To Study the
Setting of Cement
Mr. B D Kotwani
This is to certify that this project work is
submitted by ROHIT GUPTA to the Chemistry
department, Aditya Birla Public School, Kovaya was
carried out by him under the guidance & supervision
during academic year 2009-2010.
School (Head of chemistry dept.)
Aditya Birla public
I wish to express my deep gratitude and sincere thanks to Principal, Raji Jayaprasad, Aditya Birla public school, kovaya for her
encouragement and for all the facilities that she provided for this project work. I sincerely appreciate this magnanimity by taking me into her fold for which I shall remain indebted to her.
I extend my hearty thanks to Mr. B D Kotwani, chemistry teacher, who guided me to the successful completion of this project. I take this opportunity to express my deep sense of gratitude for his invaluable guidance, constant encouragement, constructive comments, sympathetic attitude and immense motivation, which has sustained my efforts at all stages of this project work.
I can’t forget to offer my sincere thanks to my classmates who helped me to carry out this project work successfully & for their valuable advice & support, which I received from them time to time.
I do hereby declare that this project work has been
originally carried under the guidance and supervision of
Mr. B D Kotwani, head of chemistry department, Aditya
Birla Public School, kovaya.
Experiment – 1
AIM : To study the setting of mixtures of cement with lime,
sand, of different qualities, rice husk, fly ash, etc……
Beakers, glass rod, weights, small wooden boxes or empty
match boxes. Lime, pit sand, river sand, cement, fly ash,
Cement is essentially a finely ground mixture of calcium
silicates (3Cao. SiO2) and aluminates (3Cao. Al2O3) which
sets to a hard mass treated with water. This property makes
cement capable of joining rigid masses like bricks, stones,
tiles etc. into coherent structures. The cements have property of setting and hardening under water due to certain
physicochemical process and are, therefore, called hydraulic cements. During setting of cement, the physical changes
taking place are gel formation and crystallization and
chemical changes are hydration and hydrolysis.
The process of solidification of cement paste involves: (i)
setting, and (ii) hardening.
Setting is stiffening of the original plastic mass into initial gel formation. After setting, hardening starts due to gradual start of crystallization in the interior of the mass. The
strength developed by cement at any time depends upon the
amount of gel formed and the extent of crystallization. A
mixture of cement, sand, small pieces of stone (gravel) and
water is known as concrete and sets to an extremely hard
When cement is used for construction purposes, it is always
mixed with sand and little water to make a pasty material
called mortar. Here cement or lime forms the binding
material and function of sand is to prevent shrinking and
cracking and to increase the bulk, thereby reducing the cost of the mortar. When cement is used as the binding material it is called cement mortar and when lime is used as the binder
it is called lime-mortar. Sand in addition to its other
functions also increases the adhesive qualities of the binding material.
Effect of quality of sand on setting of cement mortar.
Sand obtained from different sources has different qualities. For example, sea sand obtained from sea contains some
unwanted salts and retards the setting of cement and is
unsuitable for making mortar. On the other hand, pit sand