2007-12-21 04:10:40 · 5 answers · asked by Jesse Y 1 in Science & Mathematics ➔ Engineering
This is an extremely complex question, it would probably be best answered by experiment. I suspect chances are good that a significant percentage of "natural fiber" will decrease the strength since the alkali in the concrete can attack some fibers making the pretty much useless and they would be displacing some of the material that is providing strength. Some have said fibers are only good for controlling cracks, but how does concrete fail in compression?
If the fibers are not degraded by the concrete, they might increase the compression strength some (but I wouldn't expect a lot) even with random orientation, but considering the variables, experimentation is probably the only way to know.
2007-12-21 06:37:18 · answer #1 · answered by tinkertailorcandlestickmaker 7 · 0⤊ 1⤋
The 'obvious' answer to this question is: it depends on the orientation of the fiber. Because you are looking for "compressive" strength on concrete, you would want your fibers to be oriented in the direction opposing this force.
However, typically in composite structures, fibers do not offer much for compressive strength - the matrix (in other words, the resin system - which in this case is the sand, etc that makes up the concrete) offers the resistance to compressive forces. So, basically, adding fiber (longitudinally) to concrete will not improve compressive strength.
Think of the rebar they put in concrete. Those bars serve as reinforcement for deflection, not compression. Same thing would apply for fiber.
2007-12-21 12:28:10 · answer #2 · answered by miggitymaggz 5 · 0⤊ 1⤋
Nothing.
When we put fibers in the concrete, we are trying to hold the cracks together. However, according the ACI, fibers are meaningless. A few universities are testing the use of steel fibers to replace reinforcing. However, this type of use is years away from being implemented in practice because of the random behavior of the fibers. In other words how would determine the the area of steel in the direction you are interested in.
Cheers and Good luck!
2007-12-21 13:41:25 · answer #3 · answered by rutgersgroup 4 · 0⤊ 0⤋
Natural fiber, being softer than stone, would
SLIGHTLY decrease COMPRESSIVE strength.
It is added to increase TENSILE strength.
2007-12-21 14:05:05 · answer #4 · answered by Irv S 7 · 0⤊ 1⤋
fiber is for crack control, not compressive strength
2007-12-21 13:18:51 · answer #5 · answered by BMS 4 · 1⤊ 0⤋