Question

6. What are 5 different types of cement? Name all the ingredients used in concrete with their proportion.

Answer 1

1) Ordinary Portland Cement:

• Argillaceous or silicates of alumina (clay and shale)
• Calcareous or calcium carbonate (limestone, chalk, and marl)

Uses

• It is used for general construction purposes.
• It is also used in most of the masonry works.

2) Quick setting cement :

cement which sets in a very short time. The initial setting time is 5 minutes and the final setting time is 30 minutes. The composition of Quick Setting Cement:

• Clinker
• Aluminium sulphate (1% to 3% by weight of clinker)
• The aluminium sulphte increase the hydration rate of silicate.

Uses

• It is used in underwater construction.
• It is also used in rainy & cold weather conditions.
• It is used a higher temperature where water evaporates easily.
• Used for anchoring or rock bolt mining and tunneling

3) Rapid Hardening cement:

Composition:

When finely grounded Tri-calcium silicate (C3S) is present in OPC with higher content, it gains strength more quickly than OPC. This type of OPC is called Rapid Hardening Cement. It’s initial Setting Time 30 minutes and Final Setting Time 600 minutes.

Uses :

• Rapid hardening cement is mostly used where rapid construction is needed like the construction of pavement.
• It also gives high strength.

4) Pozzolans :

Natural or synthetic materials that contain silica in reactive forms. It reacts with calcium hydroxide generated by hydrating cement to form additional cementations materials when it is finely divided. The composition of Portland Pozzolana Cement:

• OPC clinker
• Gypsum
• Pozzolanic Materials (Fly ash, volcanic ash, and Calcined clay or silica fumes.

Uses

• PPC is usually used in hydraulic structures, marine structures, construction near the seashore, dam construction etc.
• It is also used in pre-stressed and post-tensioned concrete members.
• As it gives a better surface finish, it is used in decorative and art structures.
• It is also used in the manufacture of precast sewage pipes.

5) High Alumina cement:

Obtained by mixing calcining bauxite (it’s an aluminium ore) and ordinary lime with clinker during the manufacture of OPC. In which the total amount of alumina content should not be lesser than 32% and it should maintain the ratio by weight of alumina to the lime between 0.85 to 1.30

​Uses

• It is used where concrete structures are subjected to high temperatures like workshop, refractory, foundries etc
• It also used where the concrete is subjected to frost and acidic action.

>>>>Ingredients of concrete:

water, Portland cement, aggregates, and air.

The key to achieving a strong and durable concrete is mixing the ingredients in proper proportion.

Typically a concrete mixture should have the following proportions of the ingredients:

• Cement content: 10 to 15%
• Aggregates and pebbles: 60 to 75%
• Water: 15 to 20 percent
• Entrained air: 5 to 8 percent.