By Larry Horrie on Mar 4, 2022 10:51:59 AM
Bugholes are the enemy when it comes to precast concrete products, and there is no need to put up with them. Bugholes are caused by entrapped air bubbles that reach the surface but are not allowed to be released.
These oddly-named voids are pests to precast producers everywhere as they are unsightly holes left on the outer surface of concrete products. They are not ideal, especially when a solid outer finish is desired.
The proper application of vibration can help eliminate or reduce the pockmarks left on the surface. I can’t stress the importance of the word “proper” in the last sentence. There are two common approaches to vibration in concrete products:
- Internal Concrete Vibrators
- External Form Vibrators
Vibrating the mix with internal concrete vibrators requires a highly skilled operator (s) to insert the vibrating head into the mix at a certain rate, avoiding hitting the form and/or concrete reinforcement with the vibrating head, and withdraw it at a certain rate to prevent leaving internal voids. Never in the history of precast concrete have producers struggled so much with keeping workers, let alone highly-skilled workers! I recently had a conversation with a producer that, while purchasing several external form vibrators, made the comment, “if you know anybody that wants to work, send them my way!”
The use of has become the preferred method of vibrating the concrete, allowing producers to stay on their production schedule, regardless of whether their workforce shows up and/or how proficient they are.