Concerns of steam during welding on steel plate embed in concrete

[Mustangx3]

Hello all,

We have a contractor who is concerned that his welding on a steel embed plate, in technically uncured concrete (several days cure vice months), would cause steam generated from heat under the plate may damage or pop the plates. Is there a method to welding, etc. to avoid possible steam from "green" concrete slabs during welding? The plate is 12" square and will need to have a continuous 3/8 bead welded around it to join a post sitting on it. The weld is not going to be structural, just to join the post to the embed, weight bearing is in down direction only.

 

[civilperson]

Weld in small increments and then skip around to other side and repeat.

 

[unclesyd]

I've welders build a little damn around the plate and run small water stream to keep the plate cool.

 

[hogan666]

water and welding? most likely not going to be structural

 

[CocoBridgeMan]

Have your contractor consider the use of a fast-setting cement in his concrete mix. Some pre-packaged mixes can achieve earlier hydration, making for less available water to produce steam. But skip-welding as mentioned earlier is also a practical way to lessen the heat input on the plate. Incidently, concrete doesn't have to be "green" to blow-out from heat application, just having enough free water available will make it happen. I've seen more than a few overpass bridges destroyed from tanker truck fires underneath.