Correct Answer: B. Excess of alumina in the clay makes the brick crack and warp on drying.
Solution:
While a certain amount of alumina is essential for plasticity, an excess amount is detrimental. Too much alumina causes the brick to shrink excessively during the drying and firing processes. This high rate of shrinkage leads to the brick cracking and warping, making it unusable.
- (A) is incorrect; excess silica makes bricks brittle.
- (C) is related to soluble salts (efflorescence).
- (D) is incorrect; while alumina helps with impermeability, an excess amount ruins the brick.
Correct Answer: C. King closer
Solution:
A King Closer is a brick that has been cut to create a specific shape for bonding at corners. The cut removes a triangular section, starting from the center of the brick's width (on the header face) to the center of its length (on the stretcher face). This specific cut helps maintain the bond in brickwork without creating continuous vertical joints.
- A Queen Closer is a brick cut in half lengthwise.
- A Squint Brick is cut at an angle other than 90 degrees to create angled corners.
Correct Answer: C. queen closer
Solution:
A queen closer is created by cutting a standard brick in half along its length (longitudinally). This results in a brick that has the same length as a standard brick but is half the width. Queen closers are used to create the correct bond at the beginning and end of walls.
Correct Answer: D. iron oxide
Solution:
The characteristic red color of most common bricks comes from iron oxide. During the firing process in the kiln, the iron compounds in the clay oxidize, resulting in various shades of red, cherry, or brown, depending on the amount of iron and the firing temperature.
Correct Answer: D. All options are correct
Solution:
Brickwork is typically measured in cubic metres, but for single-layer or thin applications, it is measured in square metres. All the options listed fall into this category:
- Honey comb brick work: A single layer of brickwork with gaps, measured by area.
- Brick flat soling: A single layer of bricks laid flat, measured by area.
- Half brick walls: Partition walls that are only one brick-width thick (a stretcher course), measured by area.
Therefore, all the options are correct.
Correct Answer: A. 10cm
Solution:
In quantity surveying, brick walls are measured by area (in square metres) when their thickness is standard and minimal. A 10 cm thick wall, also known as a half-brick wall, falls into this category. Thicker walls, such as a 20 cm (one-brick) wall, are measured by volume (in cubic metres) as the thickness becomes a significant variable.
Correct Answer: B. Weathered clay
Solution:
Weathered clay is the most suitable raw material for making high-quality bricks. The process of weathering breaks down the clay into finer particles, which increases its plasticity and homogeneity. This natural purification process removes soluble salts and improves the overall quality of the clay, leading to stronger and more durable bricks after firing.
Correct Answer: B. Kneading
Solution:
Kneading is the process of working the clay with water to make it homogenous and plastic, ready for moulding. While "Tempering" is a broader term that includes adding water and letting it rest, "Kneading" specifically refers to the mechanical mixing action. Pugging is a form of mechanical kneading done in a pug mill.
Correct Answer: A. makes the brick brittle and weak
Solution:
Silica is essential in brick earth to prevent cracking and warping, but an excess amount is harmful. Too much silica destroys the cohesion between particles and reduces the plasticity of the clay. This results in bricks that are brittle and weak after firing.
Correct Answer: B. a depression on a face of brick
Solution:
The term frog refers to the indentation or depression on the top face of a brick. This feature serves as a key for the mortar, which improves the shear strength of the bond between brick courses. It is also often used to display the manufacturer's trademark.
Correct Answer: A. 70 kg/cm²
Solution:
According to Indian Standards, bricks are classified based on their compressive strength. For a second-class brick, the minimum compressive strength should not be less than 70 kg/cm² (which is approximately 7 N/mm²). These bricks are typically used for internal walls and other non-critical masonry work.
Correct Answer: C. tempering brick earth
Solution:
A pug mill is a machine used for the large-scale mechanical mixing and blending of clay with water. This process is known as tempering or pugging. It ensures the brick earth reaches a uniform, plastic consistency required for moulding high-quality bricks.
Correct Answer: D. arches
Solution:
A bull nose brick is a special type of brick with one or more of its corners rounded. Its primary use is to soften sharp angles in brickwork, making it ideal for rounded corners, pillars, and decorative features. However, it is not designed for constructing arches. Arches require specially shaped, tapered bricks called voussoirs to distribute loads correctly along a curve.
Correct Answer: D. Tempering of clay
Solution:
A pug mill is a machine specifically used for tempering clay. Tempering is the process of mixing clay with water and other ingredients to make it homogeneous and plastic, preparing it for the moulding stage.
Correct Answer: B. Bricks
Solution:
A Hoffman's kiln is a type of continuous, high-efficiency kiln designed for firing large quantities of clay products. It is most famously used for the mass production of bricks.
1. breaking strength test
2. impact test
3. transverse strength test
4. water absorption test
Correct Answer: D. 1, 2, 3 and 4
Solution:
All four tests are standard procedures to assess the quality of tiles. They measure key properties like strength against bending (breaking and transverse strength), resistance to sudden shock (impact), and porosity/durability (water absorption). Therefore, all are used for testing tiles.
Correct Answer: D. present of soluble salt in parent clay
Solution:
Efflorescence is the white, powdery deposit that appears on the surface of masonry. It is caused when water dissolves soluble salts present in the brick clay or mortar. As the water evaporates from the surface, it leaves the salt crystals behind. High porosity can worsen the problem by allowing more water movement, but the fundamental cause is the presence of these soluble salts.
Correct Answer: A. Maintain plasticity
Solution:
The primary and most important role of alumina in brick earth is to impart plasticity. This property allows the clay to be easily moulded into the desired brick shape without cracking or falling apart. While it contributes to other properties, maintaining plasticity is its key function.
Correct Answer: B. 30 cm
Solution:
A one-and-a-half brick wall consists of a full brick length and a half brick width, joined by a mortar joint. Using nominal dimensions for calculation:
- Thickness of one full brick = 20 cm (19 cm brick + 1 cm mortar)
- Thickness of a half brick (header) = 10 cm (9 cm brick + 1 cm mortar)
- Total thickness = 20 cm + 10 cm = 30 cm.
Correct Answer: B. 15
Solution:
According to IS 2222, the average water absorption for burnt clay perforated bricks, after immersion in cold water for 24 hours, should not exceed 15% by weight. This standard ensures the durability and performance of perforated bricks, which have different properties compared to solid bricks.