What are the main types of admixtures covered by IS 9103?

Water-reducing (plasticizers), high range water-reducing (superplasticizers), retarding, accelerating, and their combinations (e.g., retarding plasticizer). (Clause 4)

What is the maximum permissible chloride content for admixtures in reinforced concrete?

0.05 percent by mass of the admixture. (Table 2)

How is the performance of a superplasticizer evaluated?

It must reduce water content by at least 12% while maintaining workability, and the concrete must meet specific setting time and compressive strength criteria compared to a control mix without the admixture. (Table 1)

Can different admixtures be mixed together?

Mixing of admixtures should be avoided unless their compatibility is proven through trials and recommended by the manufacturer.

IS 9103

: 2009

Admixtures for concrete - Specification

CurrentFrequently UsedSpecificationBIMMaterials Science · Admixtures and Chemical Products for Concrete

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This standard provides the specifications for various types of chemical admixtures intended for use in concrete. It classifies admixtures and outlines their physical and chemical requirements, including effects on workability, setting time, strength, and limits on harmful substances like chlorides.

Specifies requirements for various types of chemical admixtures for concrete, including plasticizers, superplasticizers, retarders, and accelerators.

Quick Reference Values

Minimum water reduction for Plasticizer5%

Minimum water reduction for Superplasticizer12%

Maximum chloride content for Reinforced Concrete0.05% by mass of admixture

Minimum 28-day compressive strength vs control mix100% for most types

Minimum initial setting time extension for Retarder+60 minutes

Maximum final setting time extension for Retarder+600 minutes

Practical Notes

Always conduct compatibility tests between the specific cement, aggregates, and admixture before mass use, as performance can vary.

Adhere strictly to the manufacturer's recommended dosage range; overdosing or underdosing can lead to significant problems like excessive retardation, segregation, or loss of strength.

Ensure the specified chloride content is appropriate for the application (plain, reinforced, or prestressed concrete) to prevent long-term corrosion issues.