Pre-stressed Concrete Pipes:

They are made by tensioning high tensile wire wound spirally around cylindrical core. The core consists of either concrete which is pre-stressed longitudinally or of a thin steel cylinder which has a thick spun concrete lining to the interior.

The main advantage of pre-stressed concrete pipes is that they are found to be cheaper than other pipes above 300 mm diameter at higher pressures. By increasing the number of turns of pre-stressing wires, they can be made to stand higher pressure. They are corrosion resistant. Benefits along with such pipes are that they have got very limited flexibility and sometimes external lining to protect the pre-stressing wires get cracks when subjected to internal water pressure.

Glass Fibre Reinforced Concrete Pipes

They are relatively new product. The Alkali-resistant glass fibres are used as circumferential reinforcement placed near the outer and inner surfaces of the pipe wall. The reinforcement is better than ordinary steel and is more resistant to the normal corrosion agencies; hence lesser pipe thickness is required.