Highly acid-resistant concrete pipe, useful e.g. in cooling towers or chemical or sewage plant, with different surface densities, especially with an inner surface denser than its outer surface

摘要

Production of a highly acid-resistant pipe without an inner lining involves: (A) producing the pipe from acid-resistant concrete consisting of a binder, aggregate and water; and (B) placing the pipe in an upright casing with inner and outer parts and compressing the concrete by shaking the inner part of the casing until very fine particles form a highly acid-resistant surface on the inner part of the casing. An independent claim is also included for an acid-resistant pipe obtained as above and having a significant difference in the distribution of fine and coarse particles at the inner and outer surfaces, the inner surface especially being denser than the outer surface.