ement Lined Carbon Steel Pipe Fittings AWWA-C205Download What’s Cement Lining? Cement lined carbon steel pipe fittings are typically factory-welded butt-weld pipe fittings to ASME B16.9 with cement mortar or concrete liners. Cement mortar is a mixture of cement, fine aggregate (sand) and water. Concrete is a mixture of cement, fine aggregate (sand), coarse aggregate (gravel) and water. The cement lining, either cement mortar lining or concrete lining, is applied to the inner surface of the fittings by a proper installation method.