Vishwa Infrastructures and Services Interview Questions and Answers

Precast structures are pre-made concrete elements used in construction.

• Precast segments are manufactured off-site and transported to the construction site for assembly.

• They are commonly used in bridge construction, tunnels, and other large-scale infrastructure projects.

• Precast segments can be designed to fit specific project requirements, reducing construction time and costs.

• They offer high durability and strength, and...read more

Segment casting can be done using various methods depending on the material and application.

• One method is sand casting, where a mold is created using sand and the molten metal is poured into it.

• Another method is investment casting, where a wax pattern is created and coated with ceramic before the metal is poured.

• Die casting is a method where molten metal is forced into a mold under high pressure.

• Continuous casting is u...read more

Grade of concrete refers to its strength and durability.

• Grade of concrete is denoted by a number followed by 'M' which stands for mix.

• The number represents the compressive strength of concrete in megapascals (MPa).

• Common grades of concrete include M10, M20, M30, etc.

• Higher grade concrete has higher strength and durability.

• For example, M20 grade concrete has a compressive strength of 20 MPa.

Design mix of concrete refers to the proportion of materials used in making concrete.

• Design mix is determined based on the strength and durability requirements of the concrete.

• The mix includes cement, water, aggregates (sand, gravel, crushed stone), and sometimes admixtures.

• The proportions of each material are specified in terms of weight or volume.

• For example, a common mix for general use is 1:2:3 (cement:sand:gravel)...read more

Segment casting is a method of casting concrete segments for tunnel lining.

• Segments are cast in a factory and transported to the tunnel site.

• Segments are then assembled to form a complete tunnel lining.

• This method is commonly used in tunnel construction projects.

• It allows for faster construction and better quality control.

• Examples include the Channel Tunnel and the SMART Tunnel in Malaysia.