1) Water Absorption Test
Apparatus Required
•Weighing Balance
• Bucket
Procedure
•First of all, 5 Representative brick samples are taken and are dried in an oven under 110°C to 115°C till they attain their constant weight.
•The specimens are then removed from the oven and allwed to cool under room temperature.
•Now, the weight of each specimen are taken using weighing balance and noted. Say `W_1`.
•The specimens are then immersed inside clean water for 24 hrs.
•After 24 hrs, the specimens are removed from the water and the weight of each specimen is taken. Say `W_2`.
•Now the water absorption of each specimen is calculated as:
`(W_2-W_1)/W_1 times 100`
Remember a good brick shouldn't absorb more than 20% water of its dry weight.
-For 1st class brick: 20%
-For 2nd class brick : 22%
-For 3rd class brick : 25%
2) Compressive Strength Test
Apparatus Required
•Compressive Strength Testing Machine
• Trowel
•Tools for preparation of Mortar
Procedure
•First of all, 5 Representative brick samples are taken for testing and the specimens are submerged inside clean water for 24 hrs.
•After 24 hrs, the specimens are taken out from water and dried using a clean cloth.
•The frog (depressed portion) of brick is filled with mortar of proportion 1:3 to make the bricks of uniform section and the specimens are kept under damp jute for 24 hrs.
•The specimens are submerged inside water again for 3 days. After 3 days the specimens are taken out from water and wiped to dry it.
•The specimens are then placed in a CSTM for compression test and force of uniform rate (14N/mm/min). The max force at which the specimen fails is noted.
•Now, the compressive strength of the brick is calculated as:
`Compressive\ Streng th: (Max\ Compressive\ Fo rce\ i n\ N)/(Cross\ Section\ Area\ of\ brick)`
This process is repeated for each specimen out of five.
Remember the minimum compressive strength of 1st class brick should be 10.5N/mm², 2nd class brick should be 7N/mm² and 3rd class brick should be 3.5N/mm².
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