Mechanical protection coating for coated metal substrate

A submarine pipeline comprising:

• a metal pipe having a corrosion protecting coating thereon, said corrosion protective coating being one of an epoxy coating, a polyethylene coating, a polyurethane coating and a coal tar coating, a thin cementitious coating adhered to said corrosion protecting coating to provide mechanical protection for said corrosion protecting coating, said thin cementitious coating having substantial electrical conductivity when saturated with water, to enable cathodic protection of said pipe by an electrical current conducted through said cementitious coating, and a concrete weight coating adhered to said thin cementitious coating to counteract the buoyancy of said pipe when said pipe is filled with air.

A process for applying a concrete weight coating having large aggregate therein to a pipe having a corrosion protecting coating thereon, said corrosion protective coating being one of an epoxy coating, a polyethylene coating, a polyurethane coating and a coal tar coating, said process comprising:

• adhering to said corrosion protecting coating a thin cementitious coating to provide mechanical protection for said corrosion protecting coating, said thin cementitious coating having substantial electrical conductivity when saturated with water, to enable cathodic protection of said pipe by an electrical current conducted through said thin cementitious coating, and they applying said concrete weight coating over said thin cementitious coating, said thin cementitious coating acting as a buffer to protect said corrosion protecting coating against the impact of aggregates in said weight coating.