repairing thin concrete roof panel
repairing thin concrete roof panel
(OP)
Fellers,
I need to replace a 24"x20" section of a precast roof panel that was damaged above an elevator shaft. The panels span 8', are 24" wide with 3-1/2"x3-1/2" ribs at the edge of the panel and are 1.25" thick in the center. There is a small 4x4 mesh in the center of the 1.25" middle portion that i will replace and also dowel into the edge ribs. The concrete is a very small aggregate (1/4" max?). What should i specify for the small area of concrete needed to be filled in? What is the smallest diameter bars I can use to dowel into the 3-1/2" rib to lap with new mesh reinforcing?
thanks
I need to replace a 24"x20" section of a precast roof panel that was damaged above an elevator shaft. The panels span 8', are 24" wide with 3-1/2"x3-1/2" ribs at the edge of the panel and are 1.25" thick in the center. There is a small 4x4 mesh in the center of the 1.25" middle portion that i will replace and also dowel into the edge ribs. The concrete is a very small aggregate (1/4" max?). What should i specify for the small area of concrete needed to be filled in? What is the smallest diameter bars I can use to dowel into the 3-1/2" rib to lap with new mesh reinforcing?
thanks






RE: repairing thin concrete roof panel
RE: repairing thin concrete roof panel
The major worry is loss of section causing the beam fail whilst on works, so chec the status with the loss of section standing.
RE: repairing thin concrete roof panel
1. Carefully remove the damaged concrete.
2. Clean the mesh rebar
3. Clean the exposed conc face with steel wire brsuh to expose aggregates.
4.Apply bonding agent.
5. Place a form work below.
5. fill with good epoxy samll aggregate concrete.
6. Better order concrete from same precast plant.
RE: repairing thin concrete roof panel
- Try to square the corners of the patch area (sawcut 1/4" deep and remove concrete)
- Place a sealer around the edge of the patch work
I wouldn't worry about a bonding agent(just wet the existing surface with water) and I wouldn't order concrete from the precast plant (logistics nightmare)
If you're really concerned, you could even extend the patch to over the top of the adjacent joists, but this is not necessary with the reinforcement still intact.
RE: repairing thin concrete roof panel
Use a polymer modified concrete repair mortar such as SikaTop 123. If the repair has to be watertight, go from the bottom side after repairing the top and cover the entire area with a carbon fiber overlay to about 6 inches beyond the repair on all sides.
RE: repairing thin concrete roof panel