7 Brick Test to Decide Quality of Bricks
Brick is the oldest and extensively used construction material. Bricks are popular construction material is because of their local and cheap availability, strength, durability, reliability and insulating property against heat and sound.
Brick has a rectangular shape mostly used in building construction. Bricks are manufactured by molding mass of suitably proportioned earth in timber or steel molds. The brick prepare from mold are allowed to dry first and then burnt in kilns designed for the purpose.
The most of standard brick has a rectangular shape and of such proportion that the length is generally twice the width plus the thickness of the mortar joint. Brick thickness is less than or at the most equal to the width of the brick. The standard size of brick is such that it can be easily lifted and handled with one hand. They do not require any lifting appliances.
Various Brick Test:
It is important to conduct some tests on the brick to judge its quality. These tests are:
(i) Water absorption test
(ii) Crushing strength test
(iii) Hardness test
(iv) Shape and size test
(v) Soundness test
(vi) Test for the presence of soluble salts.
1) Water Absorption Test:
There are two tests to determine the water absorption
(i) 24-hour immersion cold water test
(ii) 5-hour boiling water test
i) 24-hour Immersion Cold Water Test:
- The dry specimen is put in an oven maintained at a temperature of 105 to 115o C, till it attains substantially constant mass.
- After cooling specimen at room temperature weight of specimen recorded as W1.
- The dry specimen is then immersed completely in the water at a temperature of 27 ± 2o C for 24 hours.
- Take out specimens from water and wipe all water from its surface with a wet cloth.
- Complete weighing of the specimen, 3 minutes after the specimen has been removed from the water.
- Let this weight be W2.
- Water absorption after 24 hours immersion in cold water is given by
- (W2 – W1) x 100 / W1
ii) 5-hour Boiling Water Test:
- The brick sample is dried in an oven at 105 to 115o C till it attains constant mass.
- Cool the brick sample at room temperature and record its weight (W1).
- The brick is immersed in boiling water for 5 hours.
- With brick immersed in water is allowed to cool at 27 ± 2o C.
- The brick sample is taken out and wipe it with a damp cloth.
- Complete the weighing of the specimen in three minutes. Let it be W3.
- Water absorption, percent by mass, is given by (W3 – W1) x 100 / W1
3) Efflorescence Test to find soluble salt in Bricks:
- Soluble salt available in brick, cause efflorescence. The presence of such salts can be determined as follows.
- Place one end of the bricks in a 25 mm depth of water in a dish of minimum diameter 150 mm and depth 30 mm.
- The dish is made of porcelain, glass, or of glazed stonework.
- The experiment is performed in a well-ventilated room between 20 to 30o C till all the water in the dish is either absorbed by the specimen or is evaporated.
- After the specimen has dried, add a similar quantity of water to the dish and let it to be absorbed by the specimen for efflorescence after the second evaporation.
- Efflorescence in brick is denoted by nil, slight, moderate, heavy or serious as defined below:
Nil: When a salt deposit is imperceptible, then it said to be Nil.
Slight: When efflorescence does not cover more than 10% of the exposed area of the bricks, it is said to be slight.
Moderate: When the deposit of efflorescence is heavier than slight and does not cover more than 50 percent of the exposed area of the brick surface. There should not powder or flake of the brick exposed surfaces.
Heavy: When the deposit covers an area of 50 percent or more of the exposed area of the brick surface. Then it is said to be efflorescence salts are heavy. There should not powder or be flaking of the brick exposed surfaces.
Serious: efflorescence is said to be serious when there is powdering or flaking of salt on the exposed surface of bricks.
Read More: EXCEL SHEET FOR BRICKWORK CALCULATION
4) Crushing Strength Brick Test:
=> For this test well brunt clay brick is selected.
=> The top and bottom face of bricks are grinded to provide smooth and even surface for the test.
=> The brick sample is then placed in water at room temperature.
=> Clean top flogs of brick and fills it with cement mortar (1 part cement and 1 part clean coarse sand of grade 3 mm and down), store under damp jute bags for 24 hours and then immerse in clean water for 3 days.
=> Take out the brick sample and clean extra water from the surface.
=> Place brick sample between two plywood sheets, each 3 mm thick, with flat faces horizontal and mortar filled face facing upwards.
=> The brick sample between plywood sheets is carefully set in the center of the compression testing machine.
=> Fix the gauge of the machine and tight it and start applying the axial load at a uniform rate of 140 kg/cm2 per minute till failure.
=> The maximum load on the dial gauge at the failure of the brick sample is noted.
=> Compressive strength = maximum load at failure/ Base are of Brick.
5) Hardness Test:
The hardness of brick can be judged with the help of the scratch of the fingernail. Try to scratch figure on brick, if no scratch is left on the surface of the brick, it is considered to be having sufficient hardness.
6) Shape and Size Brick Test:
The shape of bricks should be truly rectangle and should have standard sizes per relative code of regulation.
7) Soundness Test:
Brick soundness test is conducted by striking two brick together. Striking of brick should emit ringing sound. It can be tested by the fall of brick. A good quality brick should not break, when made to fall flat on hard ground, from a height of about 1 m.
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