What are the three fundamental properties of fresh SCC?

Filling ability (flow), passing ability (through reinforcement), and segregation resistance (stability). (Clause 5)

What is the typical slump-flow for SCC used in walls and columns?

Typically 660-750 mm, corresponding to class SF2. (Table A.1)

Can I use the standard slump test for SCC?

No, the standard slump test (IS 1199) is not meaningful for SCC. Specific tests like slump-flow, V-funnel, and L-box are required. (Annex A)

What is the maximum size of aggregate usually used in SCC?

The maximum size is generally restricted to 20 mm to enhance passing ability and reduce the risk of blocking. (Clause 4.2.3)

IS 15658

: 2006

Self-Compacting Concrete - Guidelines

CurrentSpecializedGuidelinesBIMMaterials Science · Concrete

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This standard provides guidelines on the materials, mix proportioning, properties, and testing of Self-Compacting Concrete (SCC). SCC is a high-performance concrete that flows and consolidates under its own weight without mechanical vibration, making it suitable for complex formwork and heavily reinforced structures.

Provides guidelines for the production, testing, and use of self-compacting concrete.

Quick Reference Values

Typical Slump-Flow Diameter (SF2 class)660-750 mm

Typical V-Funnel Flow Time (VS2/VF2 class)9-25 s

Typical J-Ring Step Height (PJ2 class)<10 mm

Typical Powder Content (fines <0.125mm)400-600 kg/m³

Max Coarse Aggregate Size20 mm

Coarse Aggregate Volume (as % of total)28-35 %

Practical Notes

SCC mix is highly sensitive to moisture variations in aggregates; strict moisture control is critical.

Formwork must be completely sealed and watertight to prevent leakage of the highly fluid concrete and must be designed for full liquid head pressure.

Extensive trial mixes are mandatory to establish the required fresh properties (flowability, passing ability, segregation resistance) before any site application.