DIN EN 12370:2019 pdf download.Natural stone test methods – Determination of resistance to salt crystallisation.
5 Principle
After drying to constant mass, the specimen is immersed in a solution of sodium sulphate, dried and allowed to cool to room temperature. This cycle is carried out 15 times and the percentage mass change measured.
6 Apparatus
6.1 A ventilated oven capable of maintaining a temperature of (105 ± 5) °C
6.2 A weighing instrument capable of weighing the specimens to ± 0,001 g
6.3 A room or water bath capable of maintaining the temperature of the specimens and solution to (20±0,5)°C
6.4 A 14 % solution of sodium sulphate decahydrate (i.e. 14 g of Na2 S0410H20 for every 86 g deionized water). The density of this solution at 20 °C is 1 055 kg/rn3.
7 Preparation of specimens
7.1 Sampling
The sampling is not the responsibility of the test laboratory except where specially requested. At least six test specimens, which are considered representative of the body of stone being tested, shall be selected.
7.2 Dimensions of test specimens
Cubes of (40 ± 1) mm sides shall be prepared. Specimens shall be wet diamond sawn and any surface irregularities removed by grinding.
7.3 Washing
All loose material shall be washed from the surface of the specimen using potable water.
7.4 Drying
The specimens are to be dried in an oven at a temperature (105 ± 5) °C until a constant mass is reached. This is assumed to have been attained when the difference between two weighings at an interval of (24 ± 2) h is not greater than 0,1 % of the first weighing. They are then allowed to cool to room temperature and weighed to ± 0,01 g (Md). Each specimen is then labelled with a durable tag that is wired on to the cube. The specimen is then re-weighed to ± 0,01 g (Md i).
8 Procedure
The procedure entails the use of a 14 % solution of sodium sulphate decahydrate. The density of the solution shall be checked prior to use. The solution shall only be used for one test cycle. Each of the dried specimens is placed in a 250 ml container and covered with the sodium sulphate solution to a depth of (8 ± 2) mm above the top of the specimen and the container covered to reduce evaporation. Alternatively, the specimens may be placed in a single container provided that there is a minimum of 10mm between specimens and at least 20 mm between the specimens and the sides of the container. The specimens are then left to soak for 2 h at (20 ± 0,5) °C. NOTE Changing the soaking temperature can markedly affect the results.DIN EN 12370 pdf download.