To demonstrate the power of properly reinforcing precast concrete, CCI produced a long, thin beam utilizing a custom ultra-high strength concrete mix.
The concrete beam measures 96″ long and is 6″ wide and 1.5″ thick. It weighs 75 pounds. The photos below show the beam supported by two blocks of 3″ thick rigid foam.
CCI used its basic concrete mix with metakaolin added to it to produce concrete with a compressive strength of more than 10,000 psi. The amount of reinforcing steel and its location within the concrete
beam were determined by in-house structural analysis software written by CCI.
The beam deflected more than 1.5″ under the weight of 500 lbs of play sand placed on the beam, and the tension in the steel reinforcement was estimated to be over 11,000 lbs. There were no visible cracks in either the top or the bottom of the beam.
This demonstration clearly shows the importance of reinforcement. This beam would not have been possible without using the right amount of steel reinforcement placed at the right location within the beam.
The beam before loading.
Closeup of the beam width and bag weight.
The beam with 500 lbs of play sand.No cracks at 500 lbs.
Note the deflection!
GFRC (Glass Fiber Reinforced Concrete) uses alkali resistant glass fibers instead of steel to achieve similar results. Here is a 12 foot long desk made with GFRC: