How long does it take for concrete to disintegrate?

Question

How long would it take for a building made out of concrete to decay and topple? What about other modern building materials, how long do they last?

Answer 1

Many Roman buildings made of concrete are still standing today (2000 years later.)

Modern buildings use re-enforced concrete (steel is usually added to give the concrete more tensil strength) which should last longer.

That is, unless a Jihadists crashes a jetliner full of fuel into it--in which case it takes a few moments to disentigrate completely.

The link below is to pictures (and descriptions) of many Roman buildings made of concrete that are still in use today. (The Pantheon being one of the most wonderful examples.)

Answer 2

There is an excellent example of the durability of concrete. The Romans discovered concrete and used it for many construction projects. The Pantheon in Rome has a concrete dome (the largest dome until 1781). The Pantheon has been standing since 80 CE, almost 2000 years. See the reference below.

As stated above, concrete generally gets stronger as it ages.

Answer 3

Concrete doesn't decay. It actually gets stronger with age as the hydration process never stops. What would destroy a conrete structure would be water entering seams and cracks and splitting it apart through freezing. Another way would be for climbing plants to enter the same places and force apart the seams while growing. In a place without water or plant life, concrete should last thousands of years.

Answer 4

If you do it thick enough and in the dessert probably forever. Most building are built to last 50 to 100 years. When it fails it is usually something like an i-beam or lumber.
Winds and floods usually erode the protective outer cover such as stucco. After that the beams are exposed and fall apart. That would kill a building much faster than anything concrete can do.

Answer 5

I agree with most of what has been said by others. However, roman concrete is not the same as our modern portland cement concrete.

In addition to other factors mentioned, one of the most destructive influences on a concrete building is the eroding of the soil from beneath the foundation or the saturation of this soil which would cause settlement and cracking.