Types of Tests on Bricks for Building Construction Works
Bricks have been a fundamental construction material for centuries, owing to their durability, reliability, strength, and cost-effectiveness. However, not all bricks are created equal, and it is crucial to conduct various tests to determine their suitability for construction purposes.
These tests, which can be carried out on-site or in a laboratory, play a vital role in ensuring the production of high-quality structures. In this article, we will explore the different types of tests performed on bricks to assess their quality for construction work.
1. Absorption Test on Bricks
The absorption test is conducted to measure the amount of moisture content absorbed by a brick under extreme conditions. To perform this test, dry sample bricks are weighed and then immersed fully in water for a period of 24 hours. Afterward, the wet brick is weighed and the weight difference between the dry and wet bricks is recorded. The amount of water absorbed is determined by this weight difference. For a good quality brick, the water absorption should not exceed 20% of the weight of the dry brick.
2. Crushing Strength or Compressive Strength Test on Bricks
The crushing strength test determines the ability of a brick to withstand compressive loads. The test involves placing a brick in a compression testing machine and applying load until the brick breaks. The value of the failure load is recorded, and the crushing strength of the brick is calculated. The minimum crushing strength required for a brick to be suitable for construction purposes is 3.50N/mm². If the crushing strength falls below this value, the brick is deemed unsuitable for construction.
3. Hardness Test on Bricks
The hardness test assesses a brick’s resistance to scratches from sharp objects. A sharp tool or fingernail is used to make a scratch on the surface of the brick. If no scratch impression is left on the brick, it is considered a hard brick.
4. Shape and Size Test on Bricks
The shape and size of bricks are crucial factors to consider in construction. All bricks used in a structure should have the same dimensions. The shape of the bricks should be perfectly rectangular with sharp edges. The standard size of a brick is 19cm x 9cm x 9cm (length x breadth x height). To perform this test, randomly select 20 bricks from a group and stack them along their length, breadth, and height. By comparing them, you can determine if the bricks are of the same size, thus qualifying them for construction work.
5. Color Test of Bricks
A good quality brick should exhibit a bright and uniform color throughout its body. Variations in color may indicate irregularities in the manufacturing process or the presence of impurities.
6. Soundness Test of Bricks
The soundness test assesses a brick’s ability to withstand sudden impacts. Two bricks are chosen randomly and struck against each other. A good brick should produce a clear bell ringing sound upon impact and should not break. If the brick meets these criteria, it is considered suitable for construction.
7. Structure of Bricks
To evaluate the structure of a brick, pick one brick randomly from the group and break it. Examine the inner portion of the brick carefully. It should be free from lumps and exhibit a homogeneous structure. Any irregularities or inconsistencies may indicate a lower quality brick.
8. Efflorescence Test on Bricks
Efflorescence refers to the deposit of soluble salts on the surface of a brick. A high-quality brick should not contain any soluble salts, as they can lead to aesthetic and structural issues. To determine the presence of soluble salts, place the brick in a water bath for 24 hours and then dry it in shade. Upon drying, carefully observe the brick surface. If any white or grey deposits are present, it indicates the presence of soluble salts, rendering the brick unsuitable for construction purposes.
In conclusion, conducting various tests on bricks is essential to ensure their suitability for construction work. From absorption and crushing strength tests to hardness and color tests, each assessment provides valuable insights into the quality and characteristics of bricks.
By adhering to these testing procedures, builders and contractors can select the best bricks for their construction projects, ultimately leading to the creation of safe and durable structures.