CONCRETE PIPE

Concrete pipes may be manufactured to any reasonable strength required by varying the wall thickness and the percentage of reinforcement and shape of the reinforcing cage. Concrete pipes are manufactured as non-pressure pipes with classes of NP2, NP3 and NP4. They are manufactured in sizes from 200mm to 1800mm. However, these pipes are subjected to corrosion where acid discharges into sewer or where velocities are not sufficient to prevent septic conditions or where the soil is highly acidic or containing excessive sulphates. Protective linings or coatings should be used inside and outside where excessive corrosion is likely to occur. The pipes to be laid in such situations may be manufactured with sulphate resistant cement. High alumina cement lining should be given only where the pipes are exposed to corrosive sewage or industrial wastes. NP2 pipes are not generally preferred for sewers.

Advantages of Concrete Pipes

1. Concrete pipes provide the required strength to the pipes with relatively easier modifications.
2. With socket and spigot ends the pipes could be installed with elstomeric rubber joints at faster rate.

Disadvantages of concrete pipes

1. The pipes are heavier and require lifting arrangements especially for large diameter pipes.
2. NP2 pipes are not suitable for sewers since three edge bearing strength of these pipes are much lower than NP3 and NP4 pipes.
3. Lining with high alumina cement may be required to protect the pipe from internal corrosion.