Learn about the properties of water and it's many uses in masonry.
You are watching a tutorial program aimed at introducing masonry for vocational purposes.
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In this video you will learn how to identify good quality bricks.
Bricks are rectangular blocks of clay used to build structures like walls and stairs. They are the most basic and widely available masonry units used in construction.
Since bricks are available from a variety of sources it is necessary to test the quality of a batch that has been brought to the site. Always use randomly selected samples to test a batch of bricks.
To begin testing for quality, take a sample brick and measure its dimensions to make sure that it meets with the specified size requirements. The standard dimensions of a brick measures a width of 4 inches, length of 8.5 inches and height of 2.75 inches.
Length of 8.5 inches, width of 4 inches, height of 2.75 inches.
Randomly collect 10 bricks and stack them lengthwise, widthwise and heightwise.
Closely inspect a brick to see if it is uniformly shaped, with straight edges, sharp corners and smooth surfaces.
To test the material of the brick, clap two bricks together and listen for a ringing sound when they strike.
To test for strength: Drop the brick to the floor from a height of 1 meter. Poor quality bricks will break on impact.
The colour of a good brick should be copper red. A yellowish tint of the brick indicates that the brick is under burnt while a blackish blue colour, as shown here, indicates that the brick is over burnt and brittle.
To test the brick for resistance to water, pick a sample brick from the batch and weigh it. Now, keep it immersed in water for 24 hours. Poor quality bricks absorb more than 20% of their dry weight in water.
Wipe the surface and weigh again.
To calculate by what percentage the brick’s weight has increased, use the formula given below.
The soaked brick weighs 3.10 kg, an increment of only 8.77 %. We can safely assume that based on the amount of water absorbed, this batch of bricks is of good quality.
a=weight of the dry brick & b=weight of wet brick. So (b - a)x100 / a⩽ 20%
a=2.850kg & b=3.100kg. So (3.100-2.850) x 100 / 2.850=8.77% < 20%
Additionally, to test for the presence of alkalies, place the soaked bricks to dry in the shade. If a white or grey layer forms on it, it contains alkalies, which absorb moisture. This brick is of poor quality as it has a high amount of discolouration.
You have now learned to identify good quality bricks.