Construction Concrete and Masonry 3

Question 1

What is 'efflorescence' on masonry walls?

Accepted Answer

White salt deposits on the masonry surface caused by water migration

Answer

A decorative masonry pattern

Answer

A type of mortar joint finish

Answer

Cracking due to settlement

Question 2

What type of footing is typically used for a single column load?

Accepted Answer

Spread (pad) footing

Answer

Strip footing

Answer

Mat footing

Answer

Grade beam

Question 3

What is the purpose of a 'vapor barrier' under a concrete slab on grade?

Accepted Answer

To prevent ground moisture from migrating up through the slab

Answer

To act as a slip sheet during concrete placement

Answer

To insulate the slab from ground temperature

Answer

To reinforce the bottom of the slab

Question 4

What is 'cold joint' in concrete construction?

Accepted Answer

A joint between two separate concrete pours where the first set before the second was placed

Answer

Concrete placed during cold weather

Answer

A construction joint with no reinforcement

Answer

Cracking caused by temperature changes

Question 5

Which test is used to measure the compressive strength of hardened concrete cylinders?

Accepted Answer

Cylinder compression test (ASTM C39)

Answer

Slump test

Answer

Air content test

Answer

Kelly ball test

Question 6

What is the recommended minimum thickness for a residential concrete driveway slab?

Accepted Answer

4 inches

Answer

2 inches

Answer

3 inches

Answer

6 inches