Concrete has the unique property of the plastic behaviour at its fresh or green state and then hardens to the rigid structure within a few intervals of time.
This property of concrete helps to cast it into a different shape. It also allows us to provide a different kind of surface texture with help of simple equipment.
Further, the hardened concrete has nearly equal durability and high strength as that of stone or marbles. And also it is a comparatively easier process than carving on hard surfaces of rocks or any stratum of building surface. So they are preferred for a different kind of texture surface and shapes construction.
The different type of concrete finish that can be provided over concrete are discussed below.
1) Smooth trowel concrete finish
This type of is very smooth and glossy in appearance. They are generally formed by metal plate trowels.
The surface of the concrete is either poured with cement paste slurry or cement dust and then are spread along with pressure by repetitive puss and pull action maintaining smooth elevation to the surrounding.
They are generally used for decreasing permeability of water and easy run off of water like bathroom, pathways, veranda etc.
2) Normal concrete
The concrete is generally vibrated and tamp by the wooden tampers when they are laid on the ground or over the formwork.
The tamping helps to bring the cement paste and fine aggregate above and also level the surface. Thus, they have neither very smooth finishing nor very harsh rough finishing, just leaving a natural concrete appearance.
They are generally used overall places. Above them, the layer of screeding course is added to form the desire appearance and texture. Over the rigid pavement and road, they are normally used as it is.
3) Stamped concrete finish
In this type of concrete finish, the concrete is gently pressed through the different shaped plates and rubber pads of different desirable pattern and texture after leaving concrete to set for few hours.
This type of finish gives the appearance of tiles or blocks or stone pavement to the floor.
Sometimes instead of pressing through the plates or pads, the concrete surface is well levelled with steel float or trowel and then the required border or shapes are drawn over the concrete surface by pressing the ropes or small diameter steel bars. They are used in terrace, floors, lawns, garage etc.
4) Scratched or broom concrete finish
The well-levelled plane and smooth concrete are scratched with help of a trowel or broom or the wire brush in the initially set state.
Thus, they have a very harsh and rough texture. The broom is generally made up of finely chopped bamboo woods. They are used to increase skid resistance mostly, so used in pathways to avoid slip-on walking.
However, they are also used if another layer such as tiles or punning is needed to be added over concrete. The rough surface creates good bonding with the tiles and base for the mortar.
5) Terrazzo concrete finish
Terrazzo is a specially prepared concrete surface containing white or grey cement (colours can be added to white cement) along with marble chips of different colours instead of the coarse aggregate in the proportion of 1:1.25 or 1:2.
After the spread and hardening of the concrete, the chips are exposed by grinding operation. Then are polished with different equipment and even the chemical or paint treatment is done to give a glossy shiny appearance.
Such concrete is laid only of a few cm thicknesses over the structural concrete as a topping. It gives very decorative looks and wearing properties.
6) Aggregate appearance concrete finish
These are just like Terrazzo concrete finish but here, the aggregate is used instead of marble chips. The aggregate is generally embedded and tamp over the surface of the concrete.
Then by use of power float, they are well labelled. The aggregate used usually have an aesthetically beautiful texture like quartz, basalt, granite etc, due to which they look more attractive. If the exposure is not clear, they are further subjected to the grinder to scrub and polish the surface layer.
They are also then subjected to synthetic paints or chemicals to have a shiny appearance. The embedded and exposed aggregate gives satisfactory and natural pleasant texture on the ground.
7) Salt finish concrete
In this type of concrete finish, the concrete is first of all spread to a smooth trowel finish state. And in the wet and fresh state of spread concrete, the big lumps or crystal of the salt are embedded or sprinkle all over the concrete.
The embedded salt is then later on washed with the water jet after the concrete had hardened. Thus, the salt leaves depression over the embedded place and gives natural are more satisfying irregular rough surfaces.
The surface gives an irregular appearance but is not a rough texture. They are preferred for swimming pool areas.
8) Sand blasted concrete finish
This is a method of floor finish done actually after the hardening of the concrete.
Sandblasting is techniques of corrosion of a very thin layer of the surface of the concrete (or any material) by application of pressurized blow of mix of and air. Thus, the rough texture is formed on the concrete surface.
9) Swirl / Rosette concrete finish
In every concrete finish the surface is well levelled, but in this type of concrete surface is made undulating by the intersection of any semi-circular arcs made by trowel.
The concrete surface is made undulating by suitable pressure and techniques of using trowel over the fresh slump concrete (rich in dining aggregate and cement).
The semi-circular arcs give the appearance of the Rose petals arranged on the ground, thus they are also known as Rosette concrete finish. They give a very unique aesthetic appearance to the floor.
10) Color concrete finish
These are the just normal smooth concrete finish with additional pigment causing agents.
The colour pigment is added either during the preparation of fresh concrete or are sprayed over the top surface of the concrete layer and then are smoothen by trowel. The colours are mostly available in powder form.
However concrete stains and concrete dyes are also used to create vibrant artistic colour patterns and shades over the concrete surface.
I hope this article on “Type of concrete finish” remains helpful for you.
Happy Learning – Civil Concept
Civil Engineer – Rajan Shrestha