No Fines Concrete

没有具体罚款is one type oflight weight concrete. As the name indicates, this a concrete mix without fine aggregate or sand. This type of concrete consists of only water, cement and coarse aggregate.

Important Notes on No fines Concrete

1. Normally coarse aggregatespassing 20 mm sieve and retained on 10 mm sieveis used for production of this type of concrete.
2. Theaggregates to cement ratioof no fines concrete generally vary from6:1to10:1.
3. Thewater cement ratiois kept within the range of38 to 0.52. Water cement ratio should be chosen very carefully considering the cohesiveness of the mixture.
4. Densityof no fines concrete withnormal aggregate不同from1600 to 1900 kg/m³. Whenlight weight aggregatesare used density can be as low as300公斤/米³.
5. Thecompressive strengthof no fines concrete varies between4 MPa to 14 MPa.

The uses of this type of concrete are as follow:

• Construction of external load bearing wall
• Construction of small retaining wall
• As damp proof material
• Construction of temporary structures

Advantages of No fines Concrete

1. 没有具体罚款exhibitsless drying shrinkageas compared to ordinary concrete
2. Movement of water due to capillary action is negligiblein this type of concrete.
3. Due to its light weight nature it is used in light weight concrete construction work.
4. Thermal insulating characteristicof no fines concrete isbetterthan conventional concrete. This is why it is used in the construction of external wall.
5. Production of this type of concrete results insaving of material requirement. Due to absence of fine aggregate or sand, less amount of cement is needed to produce 1 m³没有具体的罚款。
6. The density of this type of concrete is about 25 to 30% less than the conventional concrete. Therefore it exerts less pressure onformwork.
7. Segregation property of this type of concrete is very low. Therefore it can be dropped from considerable height without the danger of segregation.
8. No special equipment is needed for compaction of this concrete. Full compaction can be achieved by simple rodding operation.

Limitations of No fines Concrete

1. Due to absence of fine aggregate, this type of concretelacks cohesivenesswhile in plastic state. Therefore it requires long time for formwork removal.
2. It ismore permeablethan conventional concrete. Therefore walls constructed with no fines concrete needs an extra coat of mortar from durability point.
3. Generallyreinforcement is not recommendedin this type of concrete. However, if it is required to used reinforcement, then apply a thin layer of cement paste on the reinforcement before using it. This will improve the bonding of steel with concrete and also resistance to corrosion.
4. There existno standard test method(such asslumporcompaction factor) testto measure the consistency orworkability没有具体的罚款。只有通过适当的visual inspection and trial & error method on can judge its workability.