Materials Science Flashcards
Service life
Specified to meet the users requirement
Design life
The period of use intended by the designer
Examples of modes of deterioration
Concrete or masonry: Moisture penetration followed by chemical action or frost damage
Metals: Corrosion (e.g. damp conditions)
Timber: Fungal decay, rot, insect attack
WATER IS A COMMON FACTOR IN MOST CASES
Steel + Oxygen + Water =
Rust
High alkali cement + reactive aggregate + water =
AAR - Alkali-Aggregate Reaction eg alkali silica reaction
What are the four stages of construction projects
1) Design - the designer see.cuts materials appropriate to a structures : form and contain, intended lifetime and physical environment
2) Construction - Safety of the workforce and quality of the end product should be key considerations during construction
3) In service - Materials require regular maintenance
4) End of life (demolition) - reuse and recycling of the material as well as safety of the personnel will be of significant importance
The construction design and management regulations (2015) considers the role of?
- The client
- Designers
- Contractors
All materials must perform to an acceptable standard in regards to:
- Resisting the spread of flames
- Release of hazardous substances
- Retaining structural stability in a fire situation
Combustion requires all 3 of?
- Fuel
- Oxygen (oxidising agent)
- Heat/ignition
Examples of passive protection
Fire resistant lining boards (e.g. gypsum plasterboard)
Example of active protection
Smoke ventilation, alarm systems and sprinklers
How are materials affected by high temperature?
- Steel softens
- Concrete expands and can spall (material breaks into pieces and partially cracks below the surface causing surface to come off)
Land. Asked primary extraction can be further sub divided as?
1) Hard rock which is quarried and then crushed
2) Digging sand and gravel from areas where it has been deposited
Hard rock examples
- Igneous rocks (including granite, ‘Elvan’ (dolerite which occurs in ‘dykes’)
- Sedimentary (well cemented sandstone, some limestone)
Soft rocks examples
- Anything that is weakly cemented and crumbly
- Skate or shale which is fissile
- Mudstone, which tends to revert to the clay from which it was originally formed over time especially when broken into small pieces