Concrete Grades and Mix Ratios

What is the compressive strength of M25 grade concrete in psi?

2175psi
2900psi
4350psi
3625psi (correct)

Which of the following grades of concrete is used in the construction of foundation?

M20 and M25
M10 and M15
M30 and M35
M5 and M7.5 (correct)

What is the primary purpose of using M5 grade concrete in construction?

To provide a uniform surface for the foundation
To build footing, columns, and slabs
To construct concrete roads
To prevent direct contact of foundation concrete from the soil (correct)

Which of the following is NOT a use of M10 and M15 grades of concrete?

Construction of columns (B) Signup and view all the answers

What is the compressive strength of M40 grade concrete in Mpa?

40Mpa (C) Signup and view all the answers

What is the mix ratio of M20 grade concrete?

1:1.5:3 (D) Signup and view all the answers

What primarily affects the modulus of elasticity of concrete?

The relative proportions of the aggregates and the cement matrix (D) Signup and view all the answers

At what stress levels does the modulus of elasticity of concrete start decreasing?

At high stress levels when matrix cracking develops (A) Signup and view all the answers

What is a limitation of even the highest-grade concrete?

It is never completely waterproof (D) Signup and view all the answers

What is the primary purpose of watertight concrete?

To protect the structure from water ingress or to retain water within (A) Signup and view all the answers

What is one of the most valuable properties of concrete?

Its strength (C) Signup and view all the answers

What is the most important parameter that gives a picture of the overall quality of concrete?

Its strength (B) Signup and view all the answers

What is the primary function of weigh batchers in concrete production?

To measure the weight of concrete ingredients (B) Signup and view all the answers

What type of weigh batchers can measure the moisture content of aggregates?

Electronic weigh batchers (B) Signup and view all the answers

What is the primary concern when transporting concrete to its place of use?

Hydration of cement starts (B) Signup and view all the answers

What is the primary advantage of using crane buckets and ropeways for transporting concrete?

Transporting concrete above the ground level (D) Signup and view all the answers

What is the main objective of transporting concrete from the mixing plant to the construction site?

To maintain the intended water-cement ratio, slump, and air content (A) Signup and view all the answers

What is the primary advantage of using belt conveyers for transporting concrete?

Continuous transportation of concrete (A) Signup and view all the answers

What is unique about the curing method using infra-red radiations?

It does not result in strength loss due to rapid temperature rise (D) Signup and view all the answers

What is the primary reason for using pneumatic wheels in wheelbarrows for transporting concrete?

To prevent segregation of concrete due to vibration (A) Signup and view all the answers

What is the primary advantage of using electronic weigh batchers over mechanical weigh batchers?

They can measure the moisture content of aggregates (A) Signup and view all the answers

What is the main difficulty in rapid steam curing of concrete?

Loss of strength due to rapid temperature rise (A) Signup and view all the answers

What is the ratio of cement to fine aggregate to coarse aggregate in a 1:1:2 concrete mix using weigh batching?

50:50:100 (D) Signup and view all the answers

Why is it essential to clean and wet the mortar pan before starting concrete transportation?

To prevent the pan from sticking to the concrete (C) Signup and view all the answers

What is the purpose of using steam in concrete curing?

To achieve uniform heating and rapid strength gain (A) Signup and view all the answers

What is the term used to describe the process of transferring concrete from the mixing plant to the construction site?

Transporting (D) Signup and view all the answers

What is the benefit of using high-pressure steam curing?

It overcomes the loss of strength due to rapid temperature rise (C) Signup and view all the answers

Why is truck mixing preferred for transporting concrete over long distances?

It allows for transportation to far-off locations (D) Signup and view all the answers

What is the purpose of the pre-steaming period in low-pressure steam curing?

To prepare the concrete for steam curing (B) Signup and view all the answers

What percentage of the 28-day power can be achieved in 16 to 24 hours using low-pressure steam curing?

70% (C) Signup and view all the answers