ALUMINIUM AS A BUILDING MATERIAL

Aluminium is used as an important building material, especially in advanced countries. The following are the important properties of aluminium that make it useful as a building material:

1. Air tightness: A well-designed aluminium door, window, etc. is perfectly airtight and sealed for dust and rainwater when closed. This is a very important advantage in a modern air-conditioned building.
2. Appearance: The finished aluminium will be having a handsome appearance, and depending on the decorative style of the building, shades of various colours can be selected.
3. Ease in fabrication and assembly: As aluminium is comparatively soft and ductile, the fabrication of doors, windows, etc. can be easily carried out. An aluminium structure can easily be dismantled, transported and re-erected in different locations.
4. Handling and transport cost: Aluminium is very light and, hence, the handling and transport cost is very low.
5. High corrosion resistance: Aluminium has excellent corrosion resistance and it can resist weathering actions as well. It can also withstand extremely humid and hot dry conditions.
6. High scrap value: The scrap value of aluminium is very high, and as it hardly deteriorates, it enjoys a high resale value.
7. Maintenance cost: Due to the high corrosion resistance of aluminium, its maintenance cost is very low.
8. Noise control: Aluminium is an excellent reflector of electromagnetic and sound waves. An aluminium building is, therefore, less affected by external noises as compared to buildings made from other materials.
9. Reinforcement: Its use as reinforcement, instead of steel, will reduce foundation cost, increase durability and reduce the total cost.
10. Roofing: Corrugated sheets for roofing, window frames, etc. and many other general purpose building components can be made out of aluminium.

Duralumin is one of the most important alloys most extensively used in the aircraft industry, containing the following percentage of alloying metals, copper – 4.0 per cent, magnesium – 1.0 per cent, manganese – 0.5 per cent, silicon and iron – each 0.7 per cent and tin – 0.3 per cent. It has a specific gravity of 2.85 (compare this with 7.88 of iron) and possesses a tensile strength of 4,400 kg/cm², which is high as that of mild steel. It is susceptible to heat treatment and has the property of age hardening, i.e., once heated and quenched and left to itself, it acquires hardness by ageing in 2-3 days, when it offers considerably more resistance to corrosion.