Standard Concrete vs. Flexible Concrete

Much earlier in the semester I gave an example of how concrete acts when loaded (similar to a granola bar) but have never actually shown it. The two videos below show stress tests of, first, standard concrete and, second, flexible concrete. In the standard concrete video, failure of the material occurs at the 1:59 mark showing just how rapidly a concrete structure can go from standing and bearing the load, to immediate failure and a risk to human life. In comparison, the flexible concrete doesn't show signs of total failure under similar conditions. This is due to the higher ultimate strength which means that complete failure will, eventually, occur but at a much higher load capacity. Now, the benefit to the flexible concrete in these examples is that, by bending so greatly and still carrying the applied load, the engineer who notices the extreme bending still has time to redesign the concrete and replace the beam that is being effected without the structure collapsing. While the beam in use would still be mathematically safe to carry the loads applied, having that large of a bend within the concrete would not make people within the building feel safe because bending is a sign of imminent failure. Definitely check out the videos below. It's amazing to see how, by changing the materials in the concrete, it effects the performance of the finally designed material.