Does cement expand

Answer 1

The thermal expansion of fibre cement sheet is very small. Over the size of a 2400mm sheet, for a temperature change of 30°C, there would be much less than a millimetre change in the length of the sheet.

The expansion joints required between sheets are necessary to accommodate the movement and expansion of the material to which the sheets are fixed, which is usually much greater than that of the fibre cement sheet. (For example timber, steel, aluminium, and plastics expand more than fibre cement.)

Answer 2

• Yes, the cement expands.
• Expansion in cement is mainly due to magnesia present in it and it should not exceed 3 %.
  
• Soundness test is conducted on cement to find the expansion.
• Le Chatlier apparatus is used for this test.
• Expansion of cement should not be more than 10 mm.

Answer 3

In the same way any solid, liquid or gas expands or contracts. Temperature is not a measure of heat, but a measure of vibration. When something is cold it doesn't vibrate very much, just like people in a queue. When things get hotter they vibrate more. Imagine you are in a queue and a wasp flies in! Suddenly you are taking up a lot more space as you flap and flail around, and yet your body stays the same size. You just have more energy and have pushed the people either side of you in the queue out of the way. You have expanded how much room you need.

So, when it's cold the particles in concrete don't vibrate very much, they aren't pushing other particles out of the way. When it's hot every single particle is vibrating with more energy and pushing other particles out of the way. The only way to keep these bashing particles together is to expand to give them all the space they need.

Answer 4

Yes it infact does. Due to the bonds breaking and forming in different temperatures the concrete on side walks expand in heat and contract in the cool weather.