Question 3
- toothing;
- racking back.
-
(a) state two properties of a hardened concrete.
(b) Explain the difference between English bond and Flemish bond in wall Construction
(c) Sketch the elevation of a block wall in five courses high and indicate the following:
Observation
Most candidates were able to state two properties of hardened concrete. However, few of them failed to:
- explain the difference between English bond and Flemish bond in wall construction;
- sketch the elevation of a block wall in five courses high and indicate toothing and racking back.
The expected response to question 3 is as given below:
3 (a) Properties of hardened concrete:
Hardened concrete should:-
- be hard;
- be durable;
- have sufficient strength;
- be dense;
- be impermeable to water;
- be resistant to fire;
- be resistant to stresses;
- be resistant to wearing;
- be resistant to friction/vibration;
- be capable of carrying loads. (b) Difference between English bond and Flemish bond:
- English bond is a type of bonding brickwall in alternate courses of headers and stretchers.
- It consists of stretchers throughout the length of one course and headers throughout the length of next course.
- It is much stronger than Flemish bond.
- Flemish bond is a type of bonding brickwall in alternate headers and stretchers in the same course.
- Flemish bond gives more attractive face appearance. (c) Elevation of a blockwall.