What is the minimum grade of concrete required for prestressed concrete pipes?

The minimum 28-day compressive strength of the concrete core should be 40 N/mm² (M40).

What are the mandatory acceptance tests for PSC pipes?

The mandatory tests include the hydrostatic pressure test on every pipe and the three-edge bearing test on selected samples.

What is the minimum cover required for the high tensile prestressing wire?

A minimum concrete/mortar cover of 15 mm must be provided over the prestressing wire for corrosion protection.

Can these pipes be used for carrying aggressive sewage?

Yes, but special precautions like sulphate-resisting cement or internal protective linings must be specified if the fluid or surrounding soil is aggressive.

IS 784

: 2001

Prestressed Concrete Pipes (Including Fittings)

CurrentSpecializedSpecificationBIMWater Resources · Cement Matrix Products

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This standard specifies the requirements for the manufacture, dimensions, tolerances, and testing of prestressed concrete pipes (both cylinder and non-cylinder types) and their fittings, primarily used for water supply, drainage, and sewerage networks under pressure.

Prestressed Concrete Pipes (Including Fittings)

Quick Reference Values

minimum concrete compressive strength40 N/mm² (M40 grade) at 28 days

minimum cover to prestressing wire15 mm

factory hydrostatic test pressure1.5 times the maximum working pressure

minimum internal diameter80 mm

curing period steam curingUntil concrete attains sufficient strength (usually 24 N/mm²) to withstand prestressing forces

Practical Notes

Ensure the concrete core has achieved adequate strength before initiating wire wrapping to prevent excessive elastic shortening and creep losses.

Every single pipe must undergo a hydrostatic test at the manufacturing facility prior to dispatch; batch testing is not sufficient for pressure pipes.

Handling and transportation of PSC pipes must be done with padded slings or specialized lifting tackles to avoid chipping the protective cement mortar coating, which could lead to wire corrosion.