Concrete varies according to its preparation and also fulfills many functions, being an indispensable material in construction. As a way to go deeper into this subject, in this article you will discover the most common types of concrete.
Concrete type: Mass concrete
It’s the concrete that gets poured directly into ready-made moulds.
Mass concrete always refers to large volumes of concrete, which due to this large volume may have problems due to cracking.
Commonly, mass concrete structures have dimensions larger than 3 meters, amongst them we can mention large foundation slabs and dams.
This large volume of concrete requires measures to minimize cracking, which is caused by thermal reaction within the internal part of the concrete, which can generate a lot of heat due to the hydration process of the cement, and the external part that may be cooling.
Influencing factors during this thermal variation are: the volume of the structure, the ambient temperature, the initial temperature of the concrete at the time of its pour. The type of cement, the content of the mixture and the curing program are also influential.
As a historical anecdote, engineers Ricardo Bellsolá and Bayo used hydraulic (mass) concrete in 1862 for the first time in Spain.
In the public works magazine of 1862, it is documented that this intervention with mass concrete took place in the construction of a bridge over the Tregua river, near the town of Villanueva de Cameros (La Rioja).This bridge had a span of 22 meters, but interest laid in an adjacent work of 3 meter-span and 4.5 meters high that was executed in a monolithic way, that is, made all in one piece by using hydraulic mass concrete.
Types of concrete: Cyclopean concrete
This type of concrete is a mixture of simple concrete and large size stones.
The most correct elaboration of cyclopean concrete would be made up of 60% simple concrete and 40% of stones.
These stones must be washed before being placed into the mixture, and each one of them must be surrounded by cement.
This indicates that in this type of concrete there must be a certain distance between the stones and that this distance must be filled with concrete.
Although it is a structural element that resists compressive stresses due to the weight of the structure itself, this type of concrete has fallen into disuse.
In the past it was widely used for constructions with low loads or for enclosure fences.
Types of concrete: Cellular concrete
Aerated concrete, also called lightweight concrete, is a concrete with low density and high thermal insulation.
It’s recommended for constructions that require the least amount of weight possible as long as its mechanical performance is maintained.
Lightweight concrete consists of water, cement, polystyrene particles and admixtures.
Some of the main uses of cellular concrete are:
- Sandwich panel roofs.
- Repairs and restorations with screeds, vault fillings, leveling for wooden floors, etc…
- Leveling concrete between floors.
- Insulating cladding by using formwork on vertical surfaces in prefabricated houses.
- As thermal insulation and anti-humidity screeds to go over the ground.
- Thermo-acoustic insulation and slope formation on flat roofs.
- Repairs and restorations with screeds, vault fillings, leveling for wooden floors, etc…
- Repair and restoration of roofs and terraces in poor condition.
The following is a summary of the materials used to make lightweight concrete.
Unprocessed natural light aggregates:
- Pozzolan
- Travertines
- Lapilli
- Volcanic tuffs
Processed natural light aggregates:
- Expanded clay
- Expanded glass
- Vermiculite
- Expanded perlite
- Synthetic shale
- Expanded shale
Unprocessed light industrial aggregates:
- Blast furnace slag
- Pulverised fuel ash
Processed light industrial aggregates:
- Expanded slag
- Slag foam
- Expanded ashes
- Synthetic ashes
- Plastic particles
- Cereal husk
- Cellulosic shavings
- Porexpa
There are recommendations regarding the use of this concrete, such as pre-moistening the support’s surface, so it doesn’t take the moisture from the mixture.
Another recommendation would be to place rocks manually and carefully to avoid misplacing them and not damaging the adjacent structures.
It would also be necessary to spread the mass evenly and avoiding premature drying would be vital to ensure good curing of the concrete.
Due to its small density, this type of lightweight concrete can be nailed or sawn.
It also makes it possible to obtain large pieces and to lighten structures.
Elements that don’t require great strength can be built with a lightweight concrete, such as partitions, floor slabs and fasade cladding.
Types of concrete: Structural concrete
This type of concrete, structural concrete, is the type normally used for any type of structure, it can be either civil construction or buildings.
The main characteristic of structural concrete is to improve structure durability.
Types of concrete: Reinforced concrete
Also called reinforced concrete, it is the union of concrete with a metallic skeleton of round iron.
It provides higher resistance to compressive, tensile and torsional stresses than if it were applied without the metal skeleton.
This type of concrete is the most used to build bridges, all kinds of buildings, dams, tunnels, culverts, roads, liquid conduits, tanks, retaining walls, footings for walls, columns, and others.
Despite being so useful and offering so many benefits in building more stable structures, it also has some negative points, and that is its difficulty in making future modifications to the structure, due to the existing metal skeleton.
Features
Some of its main characteristics are:
- Anti-seismic structures are made with reinforced concrete, due to their great weight and volume.
- It has a very high strength-durability ratio.
- High traction tolerance.
- Construction styles with reinforced concrete: skyscrapers, the great Art Deco buildings of New York were achieved thanks to the use of this material.
- It does not need a lot of maintenance and it is also very durable.
- Because they have almost the same expansion coefficient, concrete and steel bond strongly.
Interesting definitions to know about reinforced concrete
Within the field of reinforced concrete construction, there are some definitions that would be good to know, among which we have:
- Main or longitudinal reinforcement: this is the one used to absorb the tensile stresses caused on thelower part in beams with combined bending.
- Secondary or transverse reinforcement: it maintains the position of the longitudinal reinforcement when the concrete is still in a fresh state and reduces the length of their curvature.
- Tying rebar: small bar or wire that is responsible for holding toguether and confining the steel bars such as stirrups and ties.
- Distribution bars: they are responsible for maintaining the distance and the correct function of the main bars in concrete slabs.
- Retraction bars: they are those that are installed in the slabs where the flexural reinforcement has only one direction.
- Anchor bars: its a bar with a seismic hook on one end, and another one no less than 90º, these must link peripheral longitudinal bars.
- Seismic hook: it’s a stirrup or tie hook with a 135º bend, which joins the longitudinal skeleton and is projected inwards.
Brief introduction to reinforced concrete historical dates
In 1854, Lambot discovered that by joining concrete with an iron reinforcement, it increased considerably and is how he built the first boat made with these materials.
In 1861 a patent was obtained for the execution of certain construction works with reinforced concrete.
In 1867 a patent was also obtained to build cubes and pipes, reducing the thickness of the structures.
Then in 1875, works of greater importance and magnitude were achieved.
In 1884, the German industry obtained the rights to Monier’s perfected patent to use in their country.
From 1890 onwards, this method of construction became generalised in most construction works.
From 1890 onwards, this method of construction became generalised in most construction works.
If you want to know more about this type of concrete, you can read this other more complete article: reinforced concrete.
Types of concrete: Prestressed concrete
Patented by Eugène Freyssinet, this type of concrete tries to overcome the natural weakness of concrete in traction.
It is built industrially, and is made of concrete and steel, which has been subjected to compressive stresses before being put into service.
The main goal of this prestressed concrete is to increase its tensile strength, by introducing artificial compression stresses before external loads are applied.
Thanks to this technique, we can achieve a higher structural load capacity, eliminating cracks during all stages. This also ensures an increased durability of the construction.
It also provides faster construction.
Acabado de hormigón pulido
Polished concrete is a finish for concrete floors. That is to say, it is a finish of concrete floors but greatly improved.
Polished concrete polishes and smooths the surface and helps prevent cracking , moisture problems, and offers a much harder and more resistant floor that allows the circulation of heavy machinery, spillage of liquids, and promises easy and economic maintenance whilst forgetting about dust problems that are no longer generated with such a finish.
The good thing about polished concrete is that it’s a valid treatment for both new and worn industrial floors.
Floors on wich the polished concrete treatment is carried out on, achieve a new appearance, in addition to the benefits in strength and durability.
In terms of aesthetics, it’s an elegant and shiny finish. It reflects light and homogenizes the entire flooring.
Below you can see a video explaining our polishing treatment and the advantages of this finish.