Bricks and Blocks Flashcards
What are the characteristics of clay and calcium silicate bricks
Clay- red in colour and has a compressive strength of 25-170 N/mm^2
Calcium silicate- yellow in colour and has a CS of 5-50 N/mm^2
What are the structural types of brick
Solid
Perforated
Frog
Coping stoves
What are the variety types of brick
Common-cheapest
Facing-looks nice
Engineered-looks nice and is strong
What are the different brick classifications
Class A-Strength>69 N/mm^2 and water absorption<4.5%
Class B-Strength>48.5N/mm^2 and water absorption<7%
What are the three classifications for frost resistance in bricks
F-frost resistant
M-moderately frost resistant
O-non frost resistant
What is mortar and what ratio is it made in
Mortar is the “glue” that holds bricks together
and is made in a 3:1 ratio of sand to cement
What are ideal properties for good mortar
Good plasticity
Able to retain water
Neither cement or water segregates
Develops strength quickly
Once developed, has similar characteristics to the bricks themselves
What is DPC and DPM
DPC-Damp Proof Course which is two or more rows of engineered bricks that don’t allow damp to spread through them
DPM-Damp Proof Membrane which is a film of plastic or another waterproof membrane that will stop damp
What is Sulphate attack
Sulphate attack is when soluble sulphate migrate into the mortar and react with the calcium molecules to expand and cause cracking
What is Frost attack
Frost attack is when cold temperatures cause water in brickwork to freeze and expand, this then melts again and the process repeats which can cause more and more cracking
What is Water ingress
Water ingress is when water enters the brickwork and discolors the bricks.
What is rising damp
A type of water ingress where water enters through the bottom and rises from brick to brick
How long does the drying process take and at what temperature
Dried for 1 day at 110 °C
but all together can take 3 days
What is an autoclave
A machine for during the bricks that uses high pressure steam-like a kiln
What does increased cement do in mortar
Quicker stiffness
Higher strength
Greater frost resistance
Less risk of sulphate attack
Less risk of rain through the mortar
What does increased lime do in mortar
More working time
More workability
Greater flexibility
Less rain through the joints
What is thin joint masonry
Alternative form of masonry that uses 2-3mm joints
It is lower skill and faster
What is efflorescence
When water dissolves into the brick and evaporates
causing a salt solution to come to the surface which is seen as white crystals
How do the two different types of brick react to moisture changes
Calcium silicate bricks shrink after drying
Clay bricks expand on taking up water after drying
What is jointing and pointing
Jointing-the process of making joints between bricks
Pointing-the process of raking out exposed jointing and refilling with mortar
What are some advantages of block work over brickwork
Faster
Cheaper
Lighter-easier construction
Can have better insulation
What are the main block types
+compressive strengths
Solid-2.9-40 N/mm^2
Cellular and Hollow-2.9-22.5 N/mm^2
What is AAC
+some properties
AAC-autoclaved aerated concrete
A light weight concrete alternative used commonly in blocks
350-700 kg/m^3
Very good thermal properties
