BS EN 196-8:2003 pdf download.Methods of testing cement — Part 8: Heat of hydration — Solution method.
4.2 Zinc oxide (ZnO) Use zinc oxide of analytical quality to determine the thermal capacity of the calorimeter. Weigh 40 g to 50 g. Ignite at (950 ± 25) o C for one hour. Cool in a desiccator. Grind to pass a 1 25 µm sieve. Store in a desiccator. 4.3 Anhydrous cement Store anhydrous cement, from which metallic iron has been removed with a magnet, in a sealed container to avoid absorption of water or carbon dioxide. Bring the test sample to ambient temperature and carefully homogenize it before use. 4.4 Hydrated cement Prepare the hydrated cement test sample by vigorously mixing, either manually or mechanically, (1 00,0 ± 0,1 ) g of anhydrous cement with (40,0 ± 0,1 ) g of distilled or deionised water for 3 min at ambient temperature. Place the resulting paste in plastics or glass cylindrical vials (three for each hydration period to be tested) so that each vial contains 1 5 g to 20 g of material. Seal the vials by means of a stopper and, if necessary, with paraffin wax or similar material and store them horizontally in a thermostatic bath maintained at a temperature of (20,0 ± 0,2) o C.
5 Apparatus 5.1 Calorimeter NOTE The method does not deal with the standardization of the calorimetric apparatus, or the measuring instruments. Insulated flasks with a volume of about 650 ml have proved to be suitable. A suitable calorimeter (see Figure 1 ) comprises the following: a) Dissolution vessel , consisting of: an insulated flask (eg. Dewar flask), placed either in a heat insulated container set inside a box constructed of insulating material (e.g. wood, plastics), or immersed in a thermostatic water bath regulated to ± 0,2 o C; and an insulated stopper (made of cork or plastics) through which holes are provided for the thermometer, the stirrer and the funnel used for introducing the sample. The insulation of the calorimeter shall ensure that the thermal leakage coefficient, K , (determined in accordance with 6.3) is less than 0,06 kelvins per 1 5 min for each kelvin above ambient temperature. The internal surface of the flask, that part of the thermometer immersed in the acid mixture and the lower part of the stopper, shall be acid mixture resistant. b) Thermometer , either a Beckmann thermometer with a 5 o C to 6 o C scale and subdivisions every 0,01 o C or other measurement apparatus of an equal or higher accuracy such as a thermistor or platinum resistance thermometer, positioned such that the end of the thermometer is at least 4 cm below the level of the liquid surface.BS EN 196-8 pdf download.