NO FINES CONCRETE:
As the name suggests by itself, no-fines concrete does not contain any fine aggregates. This concrete is produced by eliminating fine aggregates from plain concrete. Only cement, coarse aggregate, and water are used. The coarse aggregate particles are surrounded by a thin cement paste coating.
Naturally, the concrete contains a large number of voids which make the concrete lightweight and reduces its overall strength. The compressive strength of no fines concrete is very low and depends on the water-cement ratio, cement content, and aggregate grades.
No fines concrete is gaining its popularity day by day due to its various advantages over conventional concrete, which are as follows:
USES OF NO-FINES CONCRETE:
As we said earlier this concrete is not suitable for use in reinforced concrete structure. However, the walls made of no-fines concrete can be used in cold countries because of its good thermal insulating characteristics.
ADVANTAGES OF NO-FINES CONCRETE:
The principal advantages claimed for no–fines concrete are economy in materials, somewhat higher thermal insulating values, lower shrinkage, and lower unit weight. The major disadvantages are its low compressive, flexural, and bond strength, and higher permeability.
1. The density of no fines concrete is very low.
2. No fines concrete does not segregate and the capillary movement of water is almost nil.
3. It has better thermal insulating characters due to the presence of large voids.
4. This concrete can be used by dropping from a permissible height.
5. Shrinkage is also lower than normal concrete.
6. It is lightweight.
7. The formwork can be removed earlier.
8. No mechanical vibrator is required for compacting no fines concrete, simple rodding method is sufficient for full compaction.
9. It gives better and attractive appearances.
10. Production cost is comparatively lower than other conventional concrete because lower cement content is used.
DISADVANTAGES OF NO-FINES CONCRETE:
1. The strength of no-fines concrete is lower than ordinary concrete.
2. No-fines concrete cannot be used in reinforced concrete structure.