Skip to main content

Cement

Chemical Composition:-
Ordinary cement contains two basic ingredients, namely, argillaceous and calcareous. In argillaceous materials,
clay predominates and in calcareous calcium carbonate predominates.
Broadly, the raw materials used for manufacture of cement consist mainly of lime, silica, alumina and iron oxide. These oxides interact with one another at high temperature and form more complex compounds. The relative proportions of these oxide compounds are responsible for
influencing the various properties of cement, in addition to rate of cooling and fineness of grinding.

Functions Of Cement Ingredients
1. Lime (CaO): Excess lime makes the cement unsound and causes the cement to expand and disintegrate.
Deficiency in lime makes loss of strength and makes cement to set quickly.
2. Silica (SiO2): SiO2 imparts the strength to cement by forming the di-calcium and tri-calcium silicates.
Excess silica makes the strength of cement increases,but prolongs the setting time.
3. Alumina (Al2O3): Al2O3 imparts quick setting property to the cement. It acts as a flux and lowers the clinkering temperature. Excess alumina makes cement weaker.
4. Calcium Sulphate (CaSO4): It is in the form of gypsum and increases the initial setting time of cement.
5. Iron Oxide (Fe2O3): Fe2O3 imparts colour, hardness and strength to cement.
6. Magnesia (MgO): MgO imparts hardness and colour, if present in small amount. Excess MgO makes cement unsound.
7. Sulphur (S): It is useful in making sound cement.
8. Alkalis: Most of the alkalis present in raw materials are carried away by the flue gases during heating process. Presence of alkalis causes problems such as alkali-aggregate reaction, efflorescence and staining, etc.

Popular posts from this blog

Scaffolding

           When the height above floor level exceeds above 1.50 m, temporary structure, usually of Timber or steel, is erected close to work to provider safe working platform for the workers, on which work men can sit and carry the construction.The temporary frame work is known as scaffolding or simply a scaffod. Single scaffolding:-  1)Single scaffolding is usually used for brick masonry and so it is also known as brick layer's scaffolding.                                   2)Single scaffolding comprises of standards, putlogs, ledgers etc.which corresponds to the wall at a distance of around 1.2 m. Putlogs are positioned at a gap of 1.2 to 1.5 m. Double scaffolding:- 1)Stronger than single scaffolding. used in the construction of stone work framework is similar to single scaffolding except two rows and stand are provided. 2)The distance be...

Built up area , super built-up area and carpet area

Built up area :-  1. Built up Area is the carpet area plus the thickness of outer walls and the balcony.  2. Everything covered under roof. Include - external and internal walls,untiity ducts which are in the property,un- covered balcony,common staircase etc. 3. Built-up area =1.1 *carpet area. Super Built Up Area :- It is built up area plus proportionate area of common areas such as the lobby, lifts shaft, stairs, etc proportional common are like lifts, lobbies, amenities. Ex- building have 10 flats & 2000 sq .ft proportionate area which is called super built-up area. Carpet area :-Carpet area is the area that can be used to spread a carpet inside the house. 1. Actually usable area of a room. carpet area =build up area - walls -lifts , utility ducts. 2. Excluded - sanitary blocks,common staircase verandahs, corridors and passage, balcony external wall,terrace, ac duds. 3.Rera - real estate regulation act 2016. Area Measurement of a buil...