Cement / What is the Cement

PORTLAND CEMENT -

SPECIFICATIONS:

ORDINARY GREY PORTLAND CEMENT GRADE 42.5 CONFORMING TO STANDARD GB175-1999 HAVING CHEMICAL PROPERTIES: -

L.O.I. : MAX 5.0

MGO : MAX 5.0

SO3 : MAX 3.5

FINENESS : 0.08MM SIEVE MAX 10

SOUNDNESS : SOUND SETTING TIME

INITIAL SET : MIN 45 MINUTES

FINAL SET : MAX 10 HOURS

COMPRESSIVE STRENGTH :

3 DAYS : 21 MPA ,

28 DAYS : 42.5 MPA

BENDING STRENGTH

3 DAYS : 4.0 MPA,

28 DAYS : 6.5 MPA

FACTS ABOUT CEMENT:

There are about 70 varieties of cement and available in powder, paste and liquid form but we are only concerned here with constructional cement commonly known as Portland cement. (Portland is the town in South England where cement was originally made)

WHAT IS CEMENT?

Portland (constructional) Cement is a fine powder mixture of various minerals. It is produced by mixing calcareous minerals such as chalk, limestone containing silica and alumina and heating it to 1450 deg C when it cools a clinker is formed. This clinker is then finely ground and mixed with small quantity 3-5% of gypsum which has calcium sulphate in it. The amount of gypsum controls the physical properties of the eventual concrete. Sometimes very minute quantities of pigments are also added. Cement producing processes do however vary.

CEMENT FORMULA:

This formula is a very complex and no one really knows the nature and complexities of chemical/physical reactions of mixtures of cement with water (hydration)

TYPES OF PORTLAND CEMENT:

- OPC Ordinary Portland Cement

- Rapid Hardening Portland Cement

- Sulphate Resisting Portland Cement

- Low Heat Portland Cement

- White Portland Cement

- Other Cements based on Portland:

-Waterproof & water repellent Cement

-Masonry Cement

-Hydrophobic Cement

-Blast-furnace Cement

COUNTRY OF ORIGIN: