Civil Engineering Today

  Testing Methods For Clay Bricks Before recommending bricks for construction work, their suitability is to be assessed by conducting the following tests:  1. Compressive Strength Test  2. Water Absorption Test  3. Efflorescence Test  4. Dimensional Tolerance Test  5. Hardness Test  6. Soundness Test  7. Structure Test 1. Compressive Strength Test - The crushing strength of a brick is found out by placing it in a compression testing machine. It is pressed till it breaks. As per IS: 1077-1970 the minimum crushing or compressive strength of bricks is 3.50 N/mm2. The bricks with crushing strength of 7 to 14 N/mm² are graded as A. Five bricks are taken at random, and their dimensions are measured accurately to 1 mm. They are immersed in water at 25–29°C for a period of 24 hours. After that they are taken out, and excess moisture is allowed to drain. If the bricks have frogs, they are filled with C.M(cement mortar) 1:3. They are again kept under a jute...

  Tests for cement   1. Field tests 2. Laboratory tests   1. Field tests of Cement - Following tests may be carried out in the field : A.      Colour B.      Physical properties C.      Presence of lumps D.     Strength E.      Date of Packing   A. Colour - The colour of cement should be uniform. It should be typical cement colour i.e. grey colour with a light greenish shade. This is not not always a reliable test. But it gives an indication of excess lime or clay and the degree of burning. B. Physical properties - Cement should feel smooth when touched or rubbed in between fingers. If the hand is inserted in a bag or heap of cement, it should feel cool and not warm. If a small quantity of cement is thrown into the water, it should float some time before finally sinking. Then, it should sink and should not float on the surface. A thin paste of ...