| Abstract: | Corrosion protection in pipelines by concrete linings Cast iron and steel pipes of various diameters may be protected against corrosion by internal linings of cement mortar. This lining results in addition in an improvement of the mechanical properties of the composit. Within 28 days the mortar cures to compressive strength between 700 to 1000 kg/cm2 and tensile flex strength exceeding 100 kg/cm2; even when the metal tube is damaged a high pressure resistance is maintained. Adhesion between lining and metal improves with time: green cement is rather porous, so that water may penetrate to the metal; calcium hydroxide from the cement and ferric hydrates formed on the metal surface are incorporated in the concrete so that good adhesion results. Sulfate-resistant special grades have shown to be resistant in waste water containing up to 3000 mg/l sulfate and having pH-values down to 4,5 for short times. |
