In civil engineering about CEMENT & some important questions

What's cement ?

Cement is an extremely ground material having adhesive and cohesive properties which provide a binding medium for the described ingredients.

Cement can be manufacture by two process.

Dry process ( modern technology )
Wet process (old technology )

All the cement plants set up after 1980 use the dry process for manufacturing of cement.

Grade of cement ?

33 grade - mainly for plaster & masonry work
43 grade - mainly for RCC & RMC ( ready made concrete )
53 grade- mainly for Bridge, road , subway

How much cement bags in 1 cum :-

Density/ unit weight = 1440/ 50

= 28.8 bags

Volume of bag in 1 cum

Volume* density = mass

=> V = 50/1440

=> V = 0.0347cum

Filed test of cement :-

grey colour with a light greenish shade
cement should feel smooth when touched between finger
It should be free from lumps

Laboratory test of cement :-

Chemical composition test
Normal consistency test
Initial setting time test
Final setting time test
Soundness test
Strength test
Fineness test

Why is the natural cement used very limitedly ?

Because natural cement sets very quickly after addition of water. hence It is not quite workable. Artificial cement is preferred over this.

What is the average particle size of cement?

Approximately 95% of cement particles are smaller than 45 Micron and the average particle size is 15 Micron.

Which equipment is used to test setting time of cement?

Universal testing machine (UTM)

UTM can be used to test various parameter tension, bending, shear of various materials.

vicat Apparatus consists of a needle used to penetrate the cement paste sample.

What is the initial setting time of cement?

As per IS code the initial setting time of cement is minimum of 30 minute after this cement will start losing its plasticity & will not be workable

What is the final setting time of cement ?

As per Is code the final setting time of cement is 600 minute or 10 hours.

Why gypsum is added to cement ?

Gypsum plays a very important role in controlling the rate of hardening of cement. During cement manufacturing process upon the cooling of clinkers, A small amount of gypsum is introduced during the final grinding process. Gypsum is added to control the setting of cement.

Which cement is used in high temperature applications?

High alumina cement

Which apparatus is used for testing the SOUNDNESS of cement ?

The test is performed with the help of LE CHATELIER APPARATUS.

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