User talk:Aslim199

����������������� Building stones are available in large quantity in various parts of the country and to choose and utilize them for their satisfactory performance, it is necessary to test the stone for its strength properties, durability and quality. ������ ��������� �% ������ �������� Some of the tests to check the durability of stone are as follows. Of these tests, the crystallization test is prescribed by Bureau of Indian Standards. The durability (soundness) test is performed to find out the capacity of stone to resist disintegration and decomposition. ��� � %�� � Break off the freshly quarried stone chippings to about the size of a rupee coin and put them in a glass of clean water, one-third full. If the water becomes slightly cloudy, the stone is good and durable. If water becomes dirty, it indicates that the stone contains too much of earthy and mineral matter. $����)� %�� — for frost resistance — Few small pieces of freshly quarried stone are immersed in boiling solution of sulphate of soda (Glauber’s salt) and are weighed. These are then removed and kept suspended for few days and weighed again. The loss in weight indicates the probable effect of frost. ���� %�� — to check weather resistance — confirms the power of stones to withstand the atmospheric conditions. 100 g of stone chips are kept in a 5 per cent solution of H2SO4 or HCI for 3 days. Then the chips are taken out and dried. The sharp and firm corners and edges are indication of sound stone. This test is used to test the cementing material of sand stone. ���� �		��� ��� %�� 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° to 30°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° ± 5°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 = 1 2 1 W W W � where W1 is the original weight of the specimen and W2 is the weight of the specimen after 30 cycles of the test. ������������� ��������� � � ���� � %�� *���#++,+#*&�� of the unweathered spcimen should be obtained from quarry. To test stone for compressive strength, specimen pieces in the form of cubes or cylinders are made from samples of rock. The lateral dimension or diameter of test piece should not be less than 50 mm and the ratio of height to diameter or lateral dimension should be 1:1. A minimum of three specimen pieces are tested in each saturated and dry conditions. Separate tests should be made for the specimen when the load to parallel to the rift and perpendicular to the rift. In all twelve test pieces should be used. The specimen pieces of diameter or lateral dimension 50 mm are immersed in water at 20 to 30°C for 72 hours and are tested in saturated condition. The specimen pieces are also tested in �( ���������	�� � �� dry condition by drying them in an oven at 105 ± 5°C for 24 hours and then cooled in a desiccator to 20–30°C. These are tested in universal testing machine. The load is applied gently at a rate of 14 N/mm2 per minute until the resistance of the specimen piece to the increasing load breaks down and no greater load is sustained. The compressive strength of the specimen piece is the maximum load in Newtons supported by it before failure occurs divided by the area of the bearing face of the specimen in mm2. The average of the three results in each condition separately should be taken for the purpose of reporting the compressive strength of the sample. When the ratio of height to diameter or lateral dimension differs from unity by 25 per cent or more, the compressive strength is calculated by the following expression. Cc = � � � �� �� Cp 0.778 0.222 b h where Cc = compressive strength of standard specimen piece Cp = compressive strength of the specimen having a height greater than the diameter or lateral dimension b = diameter or lateral dimension h = height The crushing strength of stones varies in the range of 15–100 N/mm2. %���� ���� � ���� � %�� pieces are made in the form of blocks 200 × 50 × 50 mm. These are tested in saturated and dry conditions similar to as explained in the compressive strength test. Test apparatus used for testing is shown in Fig. 3.10. Each specimen piece is supported upon two self-aligning bearers
 * 1) *��#++,-.� Three test pieces of 50 mm diameter and 50 mm height are
 * 1) �.. Samples of stone weighing at least 25 kg each
 * 1) ��..� To test stone for transverse strength, specimen
 * 1) ��..� To test stone for transverse strength, specimen