Explain any two of the following in brief lines only)

Grades of concrete

Calcrete

Ready mix concrete

Fill in the blanks (any four)

Workability of concrete is directly proportional to

Strength of concrete with the fineness of cement.

Bulking of sand is maximum if moisture content is about

In order to obtain the best workability of concrete, the preferred shape of aggregate is

Air entrainment in the concrete increases

Select the correct option given in the brackets for the following:

Increase in the moisture content in concrete [reduces/increases/does not change] the strength.

The most commonly used admixture which prolongs the setting and hardening time is [gypsum/calcium chloride/sodium silicate].

In case of hand mixing of concrete, the extra cement to be added is

Ratio of compressive strength to tensile strength of concrete [increases with age/ decreases with age/remains constant].

For a constant water-cement ratio, decrease in aggregate -cement ratio causes [increase/decrease/no change] in workability.

Define characteristic strength of concrete. Which grades of concrete are suitable for normal RCC Which are the concrete grades generally used for lean concrete?

What is the function of ribs present on steel Enlist the properties of concrete in hardened stage. What are the factors affecting creep of concrete?

State the important raw materials used in the manufacture of cement. Draw a flow-chart to show the important steps in the manufacture of cement.

What are the physical properties of cement? Explain the requirement of water for heat of hydration in mass concrete.

Explain the procedure for determining flakiness and elongation index.

Explain with the help of a neat curve the bulking of sand and its importance.

Describe the procedure of determining the initial and final setting time of cement in the laboratory.

Explain the importance of performing sieve analysis. Define the importance of grading curve.

Explain the effect of age and temperature on the strength of concrete. Explain the hydration of cement compound.

Explain the workability of concrete mix and its importance. Enlist the various factors influencing the workability of concrete mix.

7. Write short notes on any four of the following:

Weigh and volume batching

Construction, expansion and contraction joint

Types of vibrator and their use

Advantage of steel formwork

Pre-stressed concrete

Underwater concreting