CBA Assessment

Which of the following is the main ingredient in Portland cement?

• Gypsum

• Lime

• Clay

• Silica

The initial setting time of ordinary Portland cement is approximately:

• • 15 minutes

• • 30 minutes

• • 45 minutes

• • 60 minutes

The process of hardening of concrete is known as:

• • Hydration

• • Setting

• • Curing

• Mixing

Bricks are classified as first class if their compressive strength is not less than:

• 3.5 N/mm²

• • 5.0 N/mm²

• • 7.0 N/mm²

• • 10.0 N/mm²

The maximum temperature used in the kiln for manufacturing cement is about (a)   °C.

Which of the following is a metamorphic rock?

• • A) Granite

• • Basalt

• • Marble

• • Limestone

The fire resistance of concrete is mainly due to:

• • Its density

• • Its thermal conductivity

• • Its moisture content

• • Its non-combustibility

Fill in the blank: The main chemical compound responsible for the early strength of cement is (a)   .

Which of the following tests is used to determine the workability of concrete?

• • Compression test

• • Slump test

• • Tensile test

• • Impact test

Fill in the blank: The water-cement ratio for a concrete mix affects its (a)   .

Strength