Chp 8 Masonary Units Flashcards
What is plaster and what you should know about it?
Plaster is a fluid mixture of portland cement, lime, sand and water which is used for finishing masonary walls or framed (wood) walls. Plaster is used for either exterior or interior walls. Stucco is a plaster used to cover exterior walls. The average strength of plaster is about 14MPa in 28 days.
What is Grout?
Grout is a high slump concrete consisiting of portland cement, gravel, sand and water and sometimes lime. Grout is used to fill voids in hollow masonary blocks.
What is the purpose of Grout?
Grout serves the following purposes:
Grout fills the cores or voids in hollow masonry units for the purpose of:
- Bonding the masonry units
- Bonding the reinforcing steel to the masonry
- Increasing the bearing area
- Increasing fire resistance
- Improving overturning resistance by increasing weight
What is mortar?
Mortar is a mxiture of cementitoius material, sand and water.
What is the purpose of mortar?
Mortar serves the following purposes:
- bonding masonary units together, either reinforced or non-reinforced.
- serving as seating material for the units
- levelling and settling the units
- providing aesthetic quality of the structure.
Why is curing important for masonary walls with Morter?
The weakest point of walls is the mortar. Curing is important because it increases the strength of the mortar.
What is a hollow masonry unit?
A hollow masonry unit is one which has a has a Net cross-sectional area less than 75% of the Gross cross-sectional area.
What is a Solid Masonary Unit?
It is also called a brick. It has net cross-sectional area of more than 75% the gross cross-sectional area.
Why is it important that certain masonry units meet certain absorption requirements?
To reduce the effect of weathering and limit the amount of shrinkage due to moisture loss after construction.
Describe the Mortar Cube test.
The compressive strength given by mortar cubes is lower than the actual strength of mortar because of the larger dimensions of the cube. This is also due to water cement ratio as a lower water cement ratio incrases the srength. We use 50mm cubes for the morter
Why is Lime added to morter?
For the following reasons:
- Lime extends the water retension of mortar which improves its workability, making it easier for the mason to deal with.
- Lime is added for otogenous healing.
Which propert of mortar determines the bonding betrween masnaory units?
The tensile bond strength which is relaeted to the force required to seperate the units. The more lime, the more tensile strength.
What are the types of Mortar?
There is M,S,N,O
LEED Sustainilabiliy Credits for Masoanry units:
- it promotes developments of high denisty population areas.
- helps reduce the heat variation
- good thermal insulation
- Low emitting material
