Masonry and Concrete

Question 1

what are the three main ingredients of mortar?

Answer 1

Portland cement, hydrated lime, and sand.

Question 2

Which mortar type has high compression strength and is used below grade?

Answer 2

Type M.

Question 3

What is Type N mortar used for?

Answer 3

Above-grade walls and chimneys.

Question 4

When bond and lateral strength are important, such as for long retention walls. what mortar type?

Answer 4

When is Type S mortar recommended?

Question 5

Which mortar types are mainly used for interior (cosmetic) purposes?

Answer 5

Types O and K.

Question 6

What do air-entraining admixtures do?

Answer 6

Allow mortar to resist freeze/thaw cycles.

Question 7

What is the role of accelerators in mortar?

Answer 7

They help dissipate moisture and reduce freezing in cold weather.

Question 8

What prevents mortar from freezing?

Answer 8

Calcium chloride.

Question 9

At what temperature range should mortar be placed?

Answer 9

Between 70°F and 100°F.

Question 10

How long can plastic mortar be used after mixing?

Answer 10

2.5 hours.

Question 11

How long should masonry be protected from freezing?

Answer 11

At least 48 hours.

Question 12

What is a restriction when temperatures exceed 90°F and winds are 8 mph or greater, for masonry?

Answer 12

Mortar beds should not exceed 4 feet ahead of masonry units.

Question 13

How is grout different from mortar?

Answer 13

It has a greater degree of slump (more liquid).

Question 14

Where is grout used?

Answer 14

In cavities of assembled block walls.

Question 15

What are the common width sizes for CMUs (Concrete Masonry Unit)?

Answer 15

8”, 10”, and 12”.

Question 16

How many 8x8x16” blocks are required for 8 square feet of wall area?

Answer 16

Nine blocks.

Question 17

What are the three common shapes of CMUs?

Answer 17

Stretchers, corners, and solid tops.

Question 18

What is the difference between veneer walls and cavity walls?

Answer 18

Veneer walls carry their own weight and have an air space less than 2”, while cavity walls have a cavity greater than 2”.

Question 19

What is the first step when laying CMUs?

Answer 19

Laying the first course in a mortar bed.

Question 20

What is laid first in masonry construction?

Answer 20

Corners

Question 21

What tool is used to float concrete into tight corners?

Answer 21

Darby

Question 22

Inconsistent surface finish caused by improper vibration of forms.

Answer 22

What is honeycombing in concrete?

Question 23

The first step in finishing concrete.

Answer 23

screeding

Question 24

Portland cement, fine aggregate, coarse aggregate, and water.

Answer 24

components of concrete mix

Question 25

What is the most common type of cement for general use?

Answer 25

Type 1.

Question 26

What is air entrainment used for in concrete?

Answer 26

To close up natural cracks and prevent water freezing destruction.

Question 27

Where is post-tension concrete commonly used?

Answer 27

In areas with high ground movement, such as the western U.S.

Question 28

What does pre-stressed concrete involve?

Answer 28

A slight arch to prepare for load and flex.

Question 29

Where is pre-stressed concrete used?

Answer 29

In residential construction, such as garages over basements.

Question 30

what admixture and percent is required on all exterior exposed concrete in state of michigan?

Answer 30

Air entrainment / 5 to 7%

Question 31

when pumping concrete what admixture is required to increase workability and reduce friction

Answer 31

superplasticizers (10” slump as opposed to 4”)