What are the white strips placed every so often into the concrete surrounding my pool?

[Aldee]

They are placed perpendicularly around the pool and they look like they carry water but I'm not sure about some of them. Mine are cracked and I would like to replace them along with the top of a Deck Drain that is also cracked and missing pieces. Can anyone help with this? Where to get them or what they are called would help?

 

[1poolman1]

Most likely expansion joints. Deck drain may be difficult to repair as there are so many different ones. Expansion joints can be dug out and replaced with Deck-O-Seal.

 

[JamesW]

Maybe deck drains, control joints or expansion joints.

Do you have a picture?