Cement is a product obtained by burning and crushing a well-proportioned mixture of calcareous and argillaceous materials to a fine powder. The most commonly used type of cement for making concrete is Ordinary Portland Cement, but other types such as Low Heat Cement, Rapid Hardening Cement, High Alumina Cement, White Cement, Blast Furnace Slag Cement, and Sulphate Resisting Cement are also used for special purposes.
When selecting the type of cement to use for making concrete, several factors must be considered, including the required strength of the concrete structure, the type of structure being built, and the conditions under which construction will take place.
For construction requiring high strength, 53 grade cement is typically used. This type of cement must meet certain chemical and physical requirements, including a minimum compressive strength of 53 MPa at 28 days, low levels of chloride and alkali content, and a maximum loss on ignition of 3.5%. These properties ensure that the cement can withstand the stress and pressure placed upon it in high-strength concrete structures.
| 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 | |
| (a) Lechatelier expansion (mm) | Not more than 10% | |
| (b) Auto clave expansion (%) | Not more than 0.08% | |
| 3. | Setting time (in minutes) | |
| (a) Initial setting | Not less than 30 minutes | |
| (b) Final setting | Not greater than 600 minutes | |
| 4. | Compressive strength (MPa) | |
| (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 | |
In India, tests on cement are conducted in accordance with IS 4031 (various parts) and IS 4032. The chemical tests on cement are performed using ASTM C 150. To determine the setting time of cement, ASTM C 191 and ASTM C 266 are used. Fineness tests on cement are carried out using ASTM C 150 and AASHTO M 85. In the case of blended cement, the appropriate standard is ASTM C 595.