Crystallization Test (IS 1126): Three test pieces of 50 mm diameter and 50 mm height are dried for 24 hours and are weighed (W1). The specimens are suspended in 14 per cent sodium sulphate solution (density 1.055 kg/m3) for 16 to 18 hours at room temperature (20 o to 30 o C). The specimens are then taken out of the solution and kept in air for 4 hours. They are then oven dried at a temperature of 105 o ± 5 o C for 24 hours and then cooled at room temperature. This process is repeated for 30 cycles. The specimens are weighed (W2) and the difference in weight is found. This test is repeated thirty times and the loss in weight after every five cycles is obtained. The change in weight indicates the degree of decay of stone. Durability should be expressed in percentage as change in the weight. The average of three test results should be reported as durability value.
Change in weight = W2/W1
where W1 is the original weight of the specimen and W2 is the weight of the specimen after 30 cycles of the test.