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Cement is defined as the product manufactured by burning and crushing to powder an intimate and well-proportioned mixture of calcareous and argillaceous materials.
The cement, which is generally used for preparing concrete, is the Ordinary Portland Cement. But for special purposes other qualities of cement such as Low Heat Cement, Rapid Hardening Cement, High Alumina Cement, White Cement, Blast Furnace Slag Cement, Sulphate Resisting Cement, etc. are also used.
The selection of a particular type of cement to be used for manufacturing of concrete, depends upon the following factors :
(a) The required strength of the concrete structure.
(b) The type of structure.
(c) The conditions under which the construction of structure is to take place.
Chemical and physical requirement of 53 grade cement for construction is given here. A 53 grade cement shall have the following properties.
| Sl. No. | Description | Properties |
| Chemical Requirement of 53 grade cement | ||
| 1. | Lime saturation factor | Between 0.8 to 1.02 |
| 2. | Ratio of percentage of alumina oxide to that of iron oxide | Not less than 0.66 |
| 3. | Insoluble residue (% by mass) | Not more than 3% |
| 4. | Magnesia (% by mass) | Not more than 6% |
| 5. | Sulphuric anhydride (% by mass) | Not more than 3% |
| 6. | Total loss on ignition (% by mass) | Not more than 4% |
| 7. | Chloride content (% by mass) | Not more than 0.05% |
| Physical requirement of 53 grade cement | ||
| 1. | Fineness (m2/kg) | Not less than 225 m2/kg |
| 2. | Soundness |
|
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| (a) Lechatelier expansion (mm) | Not more than 10% |
|
| (b) Auto clave expansion (%) | Not more than 0.08% |
| 3. | Setting time (in minutes) |
|
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| (a) Initial setting | Not less than 30 minutes |
|
| (b) Final setting | Not greater than 600 minutes |
| 4. | Compressive strength (MPa) |
|
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| (a) After 73 +/- 1 hours | Not less than 27 MPa |
|
| (b) After 168 +/- 2 hours | Not less than 37 MPa |
|
| (c) 672 +/- 4 hours | Not less than 53 MPa |
Tests on cement is done in India based on IS 4031 (different parts) and IS 4032. ASTM C 150 is used for chemical tests on cement. ASTM C 191 and ASTM C 266 are used for setting time of cement.
ASTM C 150 & AASHTO M 85 are used for fineness test on cement. For blended cement, ASTM C 595 is used.
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