What is the primary function of integral waterproofing compounds?

They act as pore fillers or water-repellents to reduce the water permeability of concrete or cement mortar.

Can waterproofing compounds negatively impact the setting time of concrete?

They may alter it slightly, but the standard mandates that the initial setting time must remain above 30 minutes and the final setting time below 600 minutes.

Does adding these compounds reduce the strength of the concrete?

It should not cause significant strength reduction. The standard requires the compressive strength to be at least 85% of the untreated control mix.

IS 2645

: 1994

Integral cement waterproofing compounds - Specification

SupersededFrequently UsedSpecificationMaterials Science · Admixtures and Chemical Products for Concrete

Superseded by IS 2645:2003

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This standard specifies the requirements, sampling, and testing methods for integral cement waterproofing compounds. These compounds are added to cement mortar and concrete during mixing to minimize water permeability.

Specified requirements for integral cement waterproofing compounds to be added to cement or concrete mixes to reduce permeability.

Quick Reference Values

Initial setting time>= 30 minutes

Final setting time<= 600 minutes

Compressive strength of treated mortar (3 and 7 days)>= 85% of untreated control mix

Maximum chloride content for reinforced concrete<= 0.2% by mass of admixture

Permeability reductionMust significantly reduce water absorption compared to untreated control mix

Practical Notes

Always verify the chloride content of the waterproofing compound before use in reinforced concrete to prevent rebar corrosion.

For maximum effectiveness, the compound must be uniformly dispersed in the mix; mixing it first with the gauging water is standard best practice.

Waterproofing admixtures are not a substitute for poor concrete practices; a proper water-cement ratio and adequate compaction remain essential for watertightness.