What is no-fines concrete?

It is a type of concrete composed of cement, water, and single-sized coarse aggregate, with no fine aggregate (sand), resulting in a structure with a large volume of interconnected voids.

What is a typical aggregate to cement ratio for no-fines concrete?

A common ratio is 8:1 by volume, but it can range from 6:1 to 10:1 depending on the required strength (Table 2).

Can I use standard concrete aggregates for no-fines concrete?

No, you must use single-sized coarse aggregate, typically 20 mm or 10 mm, that complies with the grading requirements in Table 1.

What is the primary application of no-fines concrete?

It is primarily used for constructing load-bearing and non-load-bearing walls in low to medium-rise buildings due to its light weight and good thermal properties.

IS 12727

: 1989

Code of practice for no-fines cast in situ cement concrete

CurrentSpecializedCode of PracticeBIMMaterials Science · Building Construction Practices incl. Painting, Varnishing

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This standard outlines the code of practice for cast-in-situ no-fines cement concrete. It covers material requirements, mix proportioning, formwork, placement, and properties of this special type of lightweight concrete, which is made without fine aggregates. No-fines concrete is characterized by its honeycomb structure, providing good thermal insulation and drainage properties, making it suitable for load-bearing and non-load-bearing walls.

Code of practice for no-fines cast in situ cement concrete

Quick Reference Values

Typical aggregate to cement ratio (by volume)6:1 to 10:1

Typical dry density1600-1900 kg/m³

Recommended water-cement ratio0.38 to 0.52

Minimum 28-day compressive strength for 8:1 mix5.0 N/mm²

Minimum 28-day compressive strength for 6:1 mix7.0 N/mm²

Primary aggregate size20 mm or 10 mm single-sized

Practical Notes

External walls made from no-fines concrete must be finished with a weather-resistant rendering to prevent rain penetration through the interconnected voids.

Do not use vibration for compaction. The concrete should only be lightly rodded or tamped into place, as over-compaction will destroy the no-fines structure.

Precise control of the water-cement ratio is critical; excess water will cause the cement paste to drain away from the aggregate, blocking the voids at the bottom of the lift.