Masonry

Question 1

Are masonry units true size?

Answer 1

No, as they give room for mortar. 10mm room.

So 400, 200 actually, 390, 190.

Question 2

History of first Mortars.

Answer 2

Fill voids between stones.
First mud, then tar.
Early mortar consisted of lime and sand
Early admixtures included egg whites, clays, urine, oxblood.

Question 3

What are the ingredients of modern mortars?

Answer 3

1) Cements - portlands, masonry or mortar.
2) Lime - improves workability and bond, hydrated calcium oxide
3) Sands - either natural or manufactured

Question 4

What is the minimum strength of mortar?

Answer 4

12.5 MPa at 28 days for structural masonry.

Question 5

What is the minimum bond strength of mortar?

Answer 5

200 kPa at 7 days for a non-structural veneer.

Question 6

What does grout do?

Answer 6

Fills voids in the wall and bonds reinforcement.

Question 7

Does grout have a high or low slump?

Answer 7

High with fine aggregates

Question 8

What compressive strength should grout have?

Answer 8

17.5 MPa

Question 9

How many methods of grouting is there?

Answer 9

4 (NZ)

Question 10

What is the best method out grouting?

Answer 10

High lift grouting with expansive admixture.

Question 11

What are the steps of High Lift Grouting?

Answer 11

1) Clean out grout space
2) Grout
3) Consolidate
4) Trowel down top after expansion

Question 12

What is the benefit of adding an admixture?

Answer 12

The reinforcing bar gets fully embedded. There are voids without this admixture.

Question 13

What is a masonry unit?

Answer 13

Specialised application of reinforced concrete.
Uses masonry as permanent formwork.
Reinforcement filled within open cells.
Reinforcement requirements same as concrete.
Standard design strength of 12 MPa