Apply vacuum and then pressure to a concrete mold
Apply vacuum and then pressure to a concrete mold
(OP)
I have considered making my own spherical molds to be easier to manage. I have wondered what would happen if I made them so that I could hook it to a vacuum pump and air compressor. My thought is if the mold was vibrated and had a vacuum applied at regular intervals while filling it, it would compact the concrete and have a smooth surface. Then when it was full, if pressure was a applied, concrete at the top half of the mold would be pressed against the mold and hopefully result in the top of the sphere having the same surface as the bottom of the sphere. As it is now, since the weight of the concrete doesn't push against the top half as much as the bottom half, the top half is always very noticeably rougher and I thought the idea could result it that problem being eliminated. Would it work or not?





RE: Apply vacuum and then pressure to a concrete mold
Professional and Structural Engineer (ME, NH)
American Concrete Industries
www.americanconcrete.com
RE: Apply vacuum and then pressure to a concrete mold
You will always have some consolidation and shrinkage as the entrapped air is released over time. You will always have some voids even with both vibration and rotation (even biaxial).
Is your aggregate pre-wetted/soaked before weighing and mixing?
Engineer and international traveler interested in construction techniques, problems and proper design.
RE: Apply vacuum and then pressure to a concrete mold