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Water absorption test is the measurement of moisture quantity that roofing tile may absorb. If water absorption is too high, the tile may suffer from cracking which is not desirable. So, this test reflects the suitability of the tile for application; roofing tile need to have substantially low absorption capacity, especially in environments subjected to rainfall, freezing, and thawing cycles. Water absorption is expressed as a percent by weight of water against the dry weight of the individual tiles.
Various codes around the world have established a method for water absorption test such American Standard for Testing Materials and Indian Standard. As per ASTM C373, typical water absorption on non-porous tiles is 0.1-0.5% while the porous products can exhibit water absorption in the range 9-15%.
Aim of the Test
To determine the percentage of water absorption of roofing tiles
- Balance or scale, of adequate capacity, suitable to weigh accurately to 0.01 g
- Oven, capable of maintaining a minimum temperature of 150 C.
Two tiles shall be used for this test from the sample selected.
- Dry the tiles selected in an oven at a temperature of 105 ° to 110 °C till they attain constant weight and then cool and weigh (M1).
- When cool, immerse the dry specimen completely in clean water at 27±2°C for 24 hours.
- Remove each specimen, wipe off the surface water carefully with a damp cloth and weigh the specimen nearest to a gram (M2) within 3 minutes after removing the specimen from the tank.
Percentage of water absorption can be computed using the following equation:
W= ((M2-M1)/M1)*100 Equation 1
W: water absorption of the specimen which is expressed in percentage
M1: weight of dry specimen
M2: weight of the specimen after 24 hours immersion in clean water.
Water absorption of the given roofing tiles= ....................%