In concrete technology, different type designations were used for different types of concrete. This classification is based on three factors:
1.Type of material used in manufacture.
2.type of stressful conditions.
3.And it's density.
Here in this article we will discuss the meaning, ingredients and types of concrete in detail.
meaning of concrete.
Table of contents
We actually live in a concrete age. It has become so important because it is used in almost all types of construction such as: (buildings, roads and highways, tunnels,damspower plants, airports and nuclear power plants).
Therefore, it is used in buildings almost outStiftungto the top floor. In transportation, it is used on roads, highways, airports, etc.
Concrete is also a material that is extensively used forwater storage and transportas in the lining of canals andwater reservoirs.
In addition to the main uses mentioned above, it is also used as a coating material for special purposes, such as: B. for waterproofing, fireproofing, soundproofing and shielding against radiation in X-ray systems and nuclear power plants.
The essential property of concrete is that it sets and hardens into a solid, rock-like mass within a short period of time.
The ultimate strength and other properties of concrete depend on several factors such as:
- The type of aggregate used.
- The quality and proportions of cement, aggregates.
- Water used in manufacturingmixture.
- And the processing.
Composition is generally expressed in relative volumes of:
- Fine aggregate (sand).
- And coarse aggregates (gravel, etc.).
So a 1:2:4 concrete indicates a mixture containing 1 part by volume cement, 2 parts sand and 4 parts gravel or crushed aggregate.
In actual mixing, the relative volumes are converted to weights of the respective materials.
The ingredients of concrete are listed below.
1.Binding agent (cement or lime).
2.Fine aggregate (sand or similar other materials).
3.Coarse aggregates (gravel, crushed stone or similar other materials).
4.Admixtures are classified as optional ingredients.
Function of the binding material.
The function of a binding material (cementor Lime) is to bind theCoarse and fine unitparticles together.
Although "Portland cement“ is the most commonly used binder material as a binder in a mix.
Much research has been done to prove that lime (especially hydraulic lime) can also be used successfully as a binder for common building methods.
Lime is economical compared to cement and also strong enough for ordinary construction.
function of aggregates.
The function of the fine aggregates is to fill any open spaces between the coarse particles. In this way, the porosity of the final mass is reduced.
The maximum grain size in fine aggregates is always below 6.35 mm. However, sand is commonly and universally used as a fine aggregate and has a grain size of about 2 mm.
And the function ofGrobe Aggregateis intended to act as the main supporting component of the concrete.
When a large number of coarse rock fragments (all larger than 6.35 mm in diameter) are held together by a cementitious material, their behavior to the imposed loads is like a very strong onerockMasse.
Choose yougravelare commonly used for this purpose.
function of water.
Water is the main component of the concrete mix. Water plays an important role in the process of chemical reaction of cement and aggregate.
function of additives.
Admixture influences thesetting time of cement, and they are mainly used for specific purposes.
Different types of concrete.
A brief overview of different types of concrete is given below.
1.Plain or ordinary concrete.
3.High density concrete.
9.Rapid hardening concrete.
12.Roller compacted concrete.
22.High strength concrete.
23.quartz smoke concrete.
So let's start from the beginning.
1. Plain or ordinary concrete.
It is one of the most commonly used types of concrete. In this type of concrete are the main componentscement, Sand ugrobe Aggregatedesigned and mixed with a certain amount of water.
The ratio of the essential components can be varied within wide limits. A very common mix design, commonly known asnominal mix design,Is1:2:4.
Plain concrete is mainly used in pavement construction and buildings where very high tensile strength is not required. It is also used in the construction ofdams.
Among the most important properties of ordinary concrete, the following can be mentioned.
- Density:2200 – 2500 Kg/m.cube.
- compressive strength:200 – 500 kg/square centimetre.
- Tensile strenght:50-100 kg/square centimeter.
- Durability:Very satisfying.
2. Lightweight concrete:
All types of concrete with a density less than1920 kg/m3is classified aslightweight concrete.
Differenttypes of aggregatesthat are used in the production of lightweight concrete are natural materials such as e.gBimssteinAndslag, artificial materials such asadvanced slatesand clays and processed materials such asperliteAndVermiculit.
The only important property of lightweight concrete is its very low thermal conductivity.
For example: Thermal conductivity - the k-value for plain concrete can be as high as 10-12. But the thermal conductivity of lightweight concrete is around 0.3.
Depending on the composition, lightweight concretes are used for thermal insulation, protection of steel structures, in long-span bridge decks and even as building blocks.
aerated concreteis a variety of extremely light concrete (density 480-800 kg/M3). This is achieved through the use of cement, sand and pulverized fuel ash as ingredients.
3. High Density Concrete:
This type of concrete is also calledheavy concrete. With this type of concrete, the density varies between 3000-4000 kg/M3.
These types of concrete are made using high density crushed stone as the coarse aggregate. Among such materials,Barytis the most commonly used material with a specific gravity of 4.5.
They are mainly used in nuclear power plants and other similar structures, as they provide good protection from all types of radiation.
4. Reinforced concrete:
It is also called RCC (Reinforced cement concrete). With this specific guyStahlin various forms is used as a reinforcement to achieve very high tensile strength.
In fact, it is due to the combined action of plain concrete (high compressive strength) and steel (high tensile strength).
The steel reinforcement is cast in the form of bars, rods, mesh and all imaginable shapes.
During the setting and hardening process, great care is taken to ensure the maximum bond between the reinforcement and the concrete.
Thus, the resulting material (RCC) is able to carry all types of loads in any type of construction. RCC is the most important type of concrete.
This term refers to numerous types of concrete forms that are poured into molds either in a factory or on a construction site.
However, they are not used in construction until they are fully set and cured in a controlled state.
Some of the examplesof precast concrete elements;precast posts, fence posts, concrete lintels, stair units, concrete blocks and cast stone, etc.
These structural and decorative elements are prepared in a well-equipped place where all the precautions are taken;
1.Perfect dosing of the concrete ingredients.
2.ThoroughMixing cement, aggregate and waterto get the mix of desired design and consistency.
3.Careful handling when transporting and inserting into the perfect design molds.
4.Perfectcure, under the controlled conditions of temperature and humidity. Even steam hardening is used to obtain high strength finished parts in much less time.
5.The latest trend in the construction industry is to switch more and more to precast concrete elements in building construction.
6. Prestressed concrete:
It is a special type of reinforced concrete in which the reinforcing bars are tensioned before they are cast in concrete.
Such tensioned wires are held at each end while the concrete mix is placed. The result is that when the concrete sets and hardens, the entire concrete parts, i.e. the casting, are put under pressure.
This type of arrangement also makes the lower section of reinforced concrete more resistant to stress, which is the main cause of stress crack development in unstressed reinforced concrete.
Since presses and stressing devices are used during prestressing, the prestressed concrete is also cast in the works.
Some of its advantages are as follows.
1.The potentialcompressive strength of concreteis increased significantly.
2.The risk of developing stress cracks in the lower sections of the beam is significantly reduced.
3.The shear resistance is greatly reduced. This largely eliminates the need for stirrups.
4.Lighter components than the unstressed (normal) reinforced concrete can be used.
5.Prestressed concrete is strongly preferred in construction;
- long-span roofs.
- Most heavy dead weight structures.
7. Air-entrained concrete:
It is a specially prepared concrete in which air is trapped in the form of thousands of evenly distributed particles.
The volume of air entrained in this way can be between 3 and 6 percent of the concrete.
The air entrainment is achieved by adding a small amount of foaming or gas-forming agents in the mixing stage.
Fatty acids, fatty alcohols and resins are some common air entraining agents.
Air-entrained concrete is more resistant to;
- Aggravated by freezing and thawing.
When the recycled glass is used as an aggregate in the concrete, this type of concrete is called glass concrete.
They offer better thermal insulation and also have a very attractive appearance compared to other types.
9. Rapid hardening concrete.
This type of concrete is mainly used in underwater construction and road repairs. Since its curing time is very short, it can be cured in just a few hours.
They are also used in building construction, where things have to be done quickly.
Asphalt concrete is a combination of aggregate and asphalt. It is also known asAsphalt. They are often used on highways, airports, as well as on embankments.
They can be cured in as little as an hour. That is the reason for its wide use in road traffic.
In this type of concrete, lime is used as a binder with the aggregates. Before the invention of cement, lime concrete was the most commonly used concrete.
In modern times, lime concrete is also used in floors, domes, etc.
This concrete is mostly used as filling material. They don't have a better strength value. They consist of lean concrete and are compacted with heavy equipment such as rollers.
Very little cement is used in this type of concrete.
13. Stamped concrete.
They are ordinary concrete with some small differences and are mainly used for architectural purposes.
A stamp of different shape and design that is applied to the concrete structures when they are in their plastic state to give a pleasing appearance.
Pigments are used for coloring purposes of various kinds to give it a more realistic and appealing look.
14. Pumped concrete.
Pumped concrete is used for high-rise buildings where concrete delivery other than pumping is not an easy task.
They are made workable enough for easy transportation. Fine material is used for better care. The more, the finer the material, the easier it is to discharge.
The pump used for pumping purposes is made of rigid or flexible materials to easily discharge the concrete.
15. Vacuum concrete.
In this type, more water is added to the concrete mix, and then the mix is poured into the formwork.
The excess water is then removed from the concrete using a vacuum pump. That's why it's called vacuum concrete.
This technique is used to get the strength of concrete early. Compressive strength is achieved within 10 days compared to 28 days for ordinary concrete.
16. Permeable concrete.
Permeable concrete is prepared in such a way that the water can be conducted into it. They have about 15 to 20% voids to allow water to pass through.
They are used in areas where stormwater problems persist.
Shotcrete is a concrete that is made in the same way as usual, but the difference is that they are placed differently.
They are placed through nozzles with the help of higher air pressure. The advantage of this technique is that the compacting and placing of the concrete takes place at the same time.
This type of concrete is prepared in concrete plants and/or transported using truck transport mixes.
Once they have arrived at the site, no further treatment is required.
The plant location will be in an adjustable location so that the concrete can be delivered ahead of timesetting timecan be started.
19. Self-consolidated concrete.
These types of concrete are compacted by their own weight, i.e. by the hardening process. There is no need to use a vibrator or perform manual compaction.
Theworkability of concreteis always high for this species. That is why it is also referred to as flow concrete.
20. Fiber Reinforced Concrete (FRC).
It is the type of concrete that uses steel fibers with a diameter of 10 to 20 microns and a length of 10 to 50 mm.
Fiber increases resilience, tensile strength, flexibility and other properties.
The fibers can be made of different materials like steel, polymer, glass, carbon or even natural fibers like coir.
Some types of fibers react with the cement; Special care must be taken when using it. It was primarily used as a top layer for walkways on bridges, airports and over industrial floors.
Fiber concrete can also be used where increased resistance to cracking is required.
21. Flying plane.
Concrete that uses fly ash is referred to as fly ash concrete. Fly ash is obtained from coal. Fly ash can be used to replace fine aggregate or cement, or to partially replace both.
Up to 30 percent replacement of fine aggregate and 20 percent replacement of cement have been reported.
Fly ash improves processability in thefresh concreteand durability and strength inhardened concrete.
Fly ash particles should be finer than cement particles.
22. High strength concrete.
High-strength concrete is concrete with a strength greater than 40 N/mm2. It is also known as high-performance concrete (HPC).
High performance concrete is used to achieve some special properties in concrete such as B. high strength, low shrinkage, self-compaction, high fire resistance, etc.
Normally the strength of such concrete should be above 60 N/mm2 (strengths up to 80 N/mm2 have been reported).
The materials used in the HPC are the following:
2.coarse and fine aggregates of the required quality,
4.Cementing additives such as silica fume, fly ash, blast furnace slag etc.
5.superplasticizers (strong water-reducing agents),
6.Air entraining agent (optional).
Note: Items 4 and 5 are the specific items needed for HPC. This type of concrete is used for special requirements in structural concrete construction.
Silica fume is a by-product of silica that is very finely divided in industry. Concrete in which silica fume is used is referred to as "Silikatstaubbeton.“
The typical concrete with normal water-cement ratio always has micropores, which limits the strength of normal concrete.
Silica fumes consist of very fine particles (actually 6 times finer than cement particles).
Hence when it is addedconcrete mix, the minute pore spaces can be reduced, resulting in high strength concrete.
Silica is also a pozzolan that contributes to strength. Thus, along with superplasticizers, silica fume is a necessary component of high-performance and high-strength concrete.
24. Polymer concrete.
Polymerization is a process of converting monomers into polymers. With normal concrete, one should have seen that micropores cannot be avoided.
The impregnation of monomer into these pores and subsequent polymerisation is a technique recently developed to reduce the porosity of concrete and improve its strength and other properties.
Listed below are the four types of polymer concrete materials that are currently available.
1. Polymer impregnated concrete (PIC).
This type of concrete is normally cured concrete that is dried in an oven and the air in the open cells is removed by vacuum.
A low viscosity monomer is introduced into these spaces, which is then polymerized by the application of chemical action or heat, or by the application of radiation.
2. Polymerportlandzementbeton (PPCC).
These types of concrete are made by mixing a monomer along with mixing aggregate, cement, and water. However, the concrete obtained by this method is not as strong as the impregnated type.
3. Polymerbeton (PC).
In this type of concrete, the polymer with the aggregates is used instead of cement. It is not real concrete as used in civil engineering terminology.
4. Partially impregnated and surface coated polymer concrete.
This name is self-explanatory. All of these materials are currently used in building construction mainly only to improve durability or for repair work.
Ferro-cement concrete is not to be confused with fiber concrete. Ferrocement consists of tightly spaced wire mesh impregnated with a rich mixture of cement mortar.
Usually, steel wires with a diameter of 0.5 to 1.0 mm are formed into meshes.
Mortar 1:2 to 1:3 with a water-cement ratio of 0.4 to 0.45 is poured into the formwork with prefabricated steel using layers of wire mesh.
The steel content of this concrete is up to 300 to 500 kg/m3 of mortar. Since the material consists of a high proportion of steel, it has high ductility and tensile strength.
The material was developed in 1940 by Italian architect P.L. Nervi to build a large number of pleasing structural forms.
In general, concrete is made by mixing different ingredients.
However, it is also possible to pack part of the ingredients (coarse grain) into the formwork and then fill the pores with specially prepared cement-sand mortar so that it fills all the pores and forms a concrete mass.
Prepacked concrete is used in special situations, e.g. B. When a large amount of concrete (such as a large machine block foundation) needs to be poured without construction joints.
One of the advantages of precast concrete is that it has very little shrinkage.
Thank you for reading this article. Please don't forget to share it.
Also read:A comprehensive guide to building concrete frame structures.
What are the types and classification of concrete? ›
Classification of concrete according to purpose
Prestressed concretes. Precast concretes. Decorative (visible) concretes. Concretes for radiation protection (heavy-weight concrete)
Concrete is made of different materials that are combined together to create a strong and durable material. There are three different types of concrete: Portland cement, aggregate, and water.What are the 6 properties of concrete? ›
- Mechanical strength, in particular compressive strength. The strength of normal concrete varies between 25 and 40 MPa. ...
- Durability. ...
- Porosity and density. ...
- Fire resistance.
- Thermal and acoustic insulation properties.
- Impact resistance.
- One-Way Flat Slab. ...
- Two-Way Flat Slab. ...
- Kitchen Slab. ...
- Sun Shade Slab. ...
- Lintel. ...
- Sunken Slab. ...
- Cable Suspension Slab. ...
- Pre-Tension Slab.
Typically, there are twenty-four different types of concrete used in the building and construction industry depending on the type of construction.