Mortar-coated steel pipes and methods of making the same

A mortar-coated steel pipe comprising:

• a steel cylinder having an outer surface;
• a mortar layer covering the outer surface;
• an intermediate layer covering an outer surface of the mortar layer to form a continuous layer thereon encapsulating the mortar layer;
• and
• an outer layer covering an outer surface of the intermediate layer, the outer layer forming an outermost surface of the pipe, wherein the outer layer is formed from the group of materials consisting of cement, mortar, and combinations thereof, and wherein the outer layer has a thickness that is greater than the mortar layer;
• wherein the intermediate layer is a polymeric film that is in direct contact with both the outer layer and the mortar layer, and that reduces crack propagation between the outer layer and mortar layer, wherein the mortar layer has a thickness in the range of from about 2 to 30 mm, and wherein the intermediate layer has a thickness in the range of from about 0.1 to 2 mm.

A method for making a mortar-coated steel pipe comprising;

• applying a mortar layer onto an outer surface of a steel cylinder;
• applying an overcoat onto an outer surface of the mortar layer to form a continuous layer thereon encapsulating the mortar layer, wherein the overcoat is provided in the form of a preformed polymeric film in direct contact with the mortar layer and is selected from the group of materials consisting of polyethylenes, polypropylenes, polyvinylchlorides, polyurethanes, polyureas, epoxies, and combinations thereof, and wherein the overcoat compresses the underlying mortar layer to provide a desired mortar layer thickness;
• and
• applying an outer layer onto on outer surface of the overcoat, wherein the outer layer is selected from the group of materials consisting of cement, mortar, and combinations thereof, wherein the outer layer has a thickness that is greater than the mortar layer, and wherein the mortar layer has a thickness in the range of from about 2 to 30 mm, and wherein the overcoat has a thickness in the range of from about 0.1 to 2 mm.

A method for making a mortar-coated steel pipe comprising;

• applying a mortar layer onto an outer surface of a steel cylinder;
• applying an intermediate layer onto an outer surface of the mortar layer to form a continuous layer thereon encapsulating the mortar layer;
• and
• applying an outer layer onto an outer surface of the intermediate layer, wherein the outer layer is selected from the group consisting of cement, mortar, and combinations thereof;
• wherein the intermediate layer is formed from a polyethylene material provided in the form of a preformed film, wherein the film is in direct contact with the underlying mortar layer, wherein the outer layer is formed from mortar and has a thickness greater than the mortar layer, wherein the mortar layer has a thickness in the range of from about 2 to 30 mm, the intermediate layer has a thickness in the range of from about 0.1 to 2 mm, and the outer layer has a thickness in the range of from about 1.2 to 4 mm.