Physical and chemical properties of cements according to European standard

Standard EN 197-1

7 Requirements for the mechanical, physical, chemical properties and durability of cement

7.1 Mechanical Requirements

7.1.1 Standard strength

The standard strength of cement is the compressive strength, determined in accordance with EN 196-1 after 28 days, and must comply with the requirements given in Table 2.

Included are three classes of standard strength: Class 32.5 Class 42.5 and Class 52.5 (see Table 2.).

7.1.2 strength fast hardening

Durability with rapid hardening cement is the compressive strength, determined in accordance with EN 196-1 after 2 or 7 days, and must comply with the requirements given in Table 2.

For each class, two classes of standard strength durability enabled by rapid hardening, the class with the usual strength with rapid hardening, indicated by the letter N, and a class with high gfochnostyu with rapid hardening, indicated by the letter R (see. Table 2).

7.2 Physical requirements

7.2.1 start of cement setting time

The start time setting, as determined in accordance with EN 196-3, shall conform to the requirements given in Table 2.

7.2.2 Persistence volume

The expansion, determined in accordance with EN 196-3, shall conform to the requirements given in Table 2.

7.2.3 Heat of hydration

The heat of hydration of conventional low heat cement (low heat cement hydration) should not exceed the value of the characteristic 270 J / g, or determined in accordance with EN 196-8 or 7 days according to EN 196-9 through 41 hours. Conventional low heat cements LH specified letters.

Note 1: The project studies the preliminary standards demonstrates the test results equivalent to EN 195-8 at 7 days and EN 196-9 after 41 hours. However, in the event of a dispute between the laboratories of the method used should be consistent.

Note 2: Cement with a high heat of hydration is suitable for some applications. It is necessary that this value has been agreed between the producer and the user, and that the cement has been identified as a cement with low heat of hydration (LH).

7.3 Chemical requirements

The properties of cement, such as the type and grade of cement strength shown in columns 3 and 4 of Table 3, respectively, shall comply with the requirements listed in column 5 of this table, when the test is conducted in accordance with the standards to which reference is made in column 2.

Note: Some European countries have additional requirements for the content of water-soluble hexahydric chromium (see Information Annex A.).

7.4 to cement durability requirements

In many specifications, particularly under adverse environmental conditions, cement ^ choice affects the durability of concrete, mortar and cement mortar, for example, cold resistance, chemical resistance and protection valves.

The choice of cement according to EN 197-1, in particular with regard to the type and strength class for different applications and exposure classes, must follow the relevant standards and / or specifications on concrete or mortar valid in the place of use.