Finishing can be defined as the process of leveling, smoothing, compacting and otherwise treating the surface of fresh concrete or recently laid concrete to give it the desired appearance.
Steps Involved in Finishing Concrete
There are 3 different steps involved in dismantling concrete, which are outlined below.
1. Scridding (Step-1)
It is the process of removing excess concrete to bring the top surface to the proper grade. When concrete is deposited, its thickness is kept slightly higher than the final finish. It is then transferred by the ‘Strike Off’ board which is known as piece of land, A sawing motion of the screed is used as it moves over the side forms. Handles are attached to each end of the screw. When the distance between the lateral forms exceeds 2 m, the screw is worked by two men.
After screeding, the voids left on the surface are filled with concrete and the process is repeated until a uniform surface results. When the mixture is dry, the screed is also used as a tamper to bring the mortar to the top for later finishing. Excessive tampering should be avoided. If the mixture is dry, the proportion should be adjusted. For larger work the screw can be fixed with rollers that run on the side form. The vibrator can also be mounted on a screw. Concrete should not overwork. This results in excessive amount of mortar and water coming to the surface. This results in less strength.
2. Floating (Step-2)
Floating involves smoothing out irregularities on the surface of the concrete that are left after screeding. This is done with a wooden float. It is about 1.5 m long and 20 cm wide, attached to a handle. The low spots are filled with concrete and worked with a float. Filling of the lower spots with mortar should be avoided as it results in soft non-uniform surface. Finishing is done with a back and forth motion of the float. In places where long handle floats are difficult to operate, wooden floats with handles up to 60 cm long and 10 to 12 cm wide can be used.
If the area of the slab is large and there are no walls and posts, a bull float is used. It serves the same purpose as a float. It has a wooden or aluminum blade 2 cm wide and 1.0 to 1.5 m long. It is attached to a 5 meter long handle. This allows it to float on concrete without operators.
3. Troweling (Step-3)
This is the final finishing operation. It provides a smooth finish that is hard and abrasion resistant. Troweling may be necessary to eliminate points that do not end up satisfactorily by floating. This should be done after all the excess water has evaporated. Troweling with a steel float when the concrete is almost dry gives a very smooth finish. The trowel is 25 to 50 cm long and 8 to 12 cm wide. Blades serve better after enough use. Power trowels can also be used for larger tasks.