I guess never too old to learn---- pipeline guys told me about rust and cement......

Pipeline guys were filling huge bags with tires and sand...probably 6x6x6.

Finally my curiosity won.........and I asked why?

They told me that they used to use cement collars on the pipe to hold the pipe from buckling upwards-----

---- now they use these big bags of tires and sand on top of the pipe,

because the cement collars caused rust on the pipes between cement and pipe.