You already know that compaction is an important process after placing of concrete. Here I am going to write about the different methods of compaction of concrete used in the site.
Compaction reduces the percentage of air voids in the concrete, thus it can increase the strength of concrete over a large extent. Scientific studies show that about 1 % of air voids can decrease the compressive strength by 6 %. Such air voids should be avoided as you know that the concrete is the main material which takes the compressive load in the structural members.
Different methods of compaction of concrete
You can do compaction of concrete by two methods, hand compaction and mechanical compaction. First, we move on to hand compaction
You may have already seen hand compaction in various places because it is a widely used compaction method in construction works. Nowadays it is used only for small construction works and unimportant or temporary construction works. The different types of hand compaction of concrete are given below.
Rodding is a method of poking concrete with a rod. The rod used for poking has a length of 2m and 16mm diameter. The thickness of layers of poking varies from 15 to 20mm.
Tamping is a method in which the top surface of the concrete is tamped or beaten by a wooden cross section road. Tamping is mainly used for the construction of roof slabs and pavements. By tamping, you can achieve levelling and compaction at the same time.
It is not used for the compaction in reinforced concrete works or upper storeys floors. Widely used for the compaction of ground floors.
In mechanical compaction, vibrators are used. The vibrators can vibrate within the fresh concrete so that proper compaction occurs without any air voids. While compaction, the air bubbles in the concrete comes out at the top surface and it expells immediately.
a. Internal Vibration
Internal vibration is widely used for mechanical vibration methods. The diameter of the needle varies from 20 to 75 mm and its length is about 90cm.
External vibrations are normally used where internal vibrations are not possible. The formwork should have sufficient strength. External vibrations has less efficiency compared to internal vibrations and it consumes more energy.
Table vibrator is normally used in laboratories. In laboratories, concrete is set up on a table and compaction takes place due to the vibration of the table.
These are the different Methods of Compaction of Concrete