The developments in technology have led to the invention of new types of concrete with specific uses. In this article, we will discuss different types of concrete used in construction.
What Is Concrete?
Concrete is a construction material obtained by mixing cement, fine aggregate (sand) coarse aggregates (gravel, stone chips, rock, etc.), and water in certain proportions.
All these ingredients when properly mixed, cement and water start a reaction to bind themselves producing a plastic mass that hardens over time. This plastic and hardened mass is known as concrete.
The properties of concrete depend upon the quantity and proportions of the ingredients used in the mix. However, the properties can also be majorly modified based on the various type of cement used for the mix.
Concrete is very strong in compression but little in tension. Fresh concrete can be poured into any suitable form or mould to get desired shape and size. Concrete is widely used in all types of construction work like buildings, bridges, dams, roads, flyovers, etc.
Types Of Concrete
There are 25 different types of concrete discussed below.
1. Plain Cement Concrete (PCC):
Plain Cement Concrete is a basic concrete mix consisting of cement, fine aggregates, coarse aggregates, admixtures (optional), and water. PCC is very strong in compression. But, due to the absence of reinforcements like steel, it is very weak in tension.
The general mix design ratio of PCC is 1:2:4 and 1:3:6. It is commonly used in the foundation of a building. After the hard strata have been reached, a layer of sand is laid followed by Plain Cement Concrete. Above the Plain cement concrete, the reinforcement cage of the footing is placed.
Applications:
- Foundations,
- Grade slabs,
- Concrete blocks,
- Verandas,
- Open Parking.
2. Reinforced Cement Concrete (RCC)
Reinforced cement concrete is a composite material made up of cement, fine aggregates, coarse aggregates, admixtures, and steel reinforcements. It is simply Plain cement concrete with the presence of steel in it.
All the limitations in Plain cement concrete can be overcome by reinforced cement concrete. Of all metals, steel is the most suitable reinforcement material because of the near same thermal coefficient of expansion.
The thermal coefficient of concrete is 14.5 /˚C and that of steel is 12 /˚C. Due to this property of steel, it is more compatible with concrete than other metals.
Applications:
- Slabs, beams, columns, and foundations of buildings
- Dams
- Pavements
- Bridges
- Water tanks
- Retaining walls
- Underwater constructions
- Concrete sewers and pipes
- Canals.
- Chimneys.
- Power plants.
3. Fibre Reinforced Concrete (FRC):
Fiber-reinforced concrete is a composite material made up of cement, water, aggregates, and flat or rounded fibres. Various types of fibres like steel fibres, polypropylene fibres, glass fibres, asbestos fibres, carbon fibres and organic fibres are widely used to reduce permeability, bleeding and the formation of minor cracks.
Fibres are added in the ratio of 0.1% to 3% of the total volume of the concrete. The dimensions of the fibres are represented using the term “aspect ratio” which is the ratio of the length to the diameter of the fibre.
The aspect ratio of the fibre is generally 30 to 150. The orientation of the fibres is mostly random but they can be arranged in parallel or perpendicular fashion depending on the design criteria.
Applications:
- Dams, spillways, basins
- Pavements in airports and highways
- Bridge decks
- Thin shelled structures
- Foundation
- In refractories
- Industrial floors
- Machine foundation
4. Glass Fibre Reinforced Concrete (GFRC)
Glass Fibre reinforced concrete is a composite material made up of cement, water, aggregates, and glass fibres. The glass fibres have high tensile strength of nearly 4080 N/mm2.
The glass fibres also increase the durability of the structure due to their alkaline nature. However, glass fibres are one of the cheapest reinforcements available thus making the structure more economical.
The properties, applications, advantages and disadvantages of glass fibre reinforced concrete are similar to that of fibre reinforced concrete that is discussed above.
5. Ferro Concrete:
Ferro concrete also called Ferrocement is a type reinforced concrete structure made up of cement, fine aggregates, chicken wire mesh, and water.
First, a tightly packed wire mesh is installed over which a rich cement mortar mix of ratios 1:2 or 1:3 is applied to both sides of the wire mesh.
The diameter of the holes in the wire mesh is restricted to 1 mm. The application of the mortar to the wire mesh can be through hand plastering, centrifuging, machinal, or guniting.
Applications:
- Slabs
- Manhole covers
- Showcases
- Roof shells
- Water tanks and septic tanks
- Gobar gas units
- Stone benches
- Concrete pipes
- Industrial structures
- Bridge decks
6. Ready Mix Concrete
Ready mix concrete is a factory-made concrete made of cement, aggregates, water, and admixtures and transported to the site. The ready-mix concrete is preferred when there is less space for storing and mixing the construction materials.
The plant-made concrete is loaded into special delivery trucks called the transit mixers which have the provisions to constantly rotate and keep the concrete in motion and thus prevent setting.
Usually, retarders are added to the concrete mix to slow down the setting process to give allowance to the transportation and placing the time of the concrete. Quality check is performed both in the factory and at the site.
The difference in the slump value of both should not differ by more than 25 mm or 1/8th of the specific value whichever is greater.
Applications:
- Normally used for monolithic concreting of the roof slabs and beams
- Runways
- Pavements
- Lining of tunnels
- Dams and hydraulic structures
7. Precast Concrete
Precast concrete structures are cast, cured, transported to the site, and erected using cranes. The precast structures are manufactured at the sites using moulds with reinforcement cages present inside them.
They may or may not be prestressed based on requirements. The dried concrete members are cured in controlled conditions to achieve the desired strength.
Special hooks are provided to the members to lift them. The design of precast members takes into account the handling and erection stresses that may arise during the construction process.
Applications:
- Precast slabs, beams, columns, wall panels can be used for conventional buildings
- Bridge decks
- Parking
- High rise buildings
- Retaining walls
- Sound walls
- Culverts
8. Prestressed Concrete
Prestressed concrete structures are made up of high-strength concrete and high-strength steel tendons in addition to the normal reinforcements. When the tendons are prestressed, the stress from the tendon is transferred to the concrete.
Thus it improves the deflection resistance, load capacity, and overall structural performance of the member. Prestressed concrete structures are commonly used in the construction of prefabricated buildings.
A concrete member can be prestressed in two ways:
1. Pre-tensioning
2. Post-tensioning
Pretensioned prestressed structures are prestressed before the concrete hardens. First, the high strength tendons are pulled and the concrete is cast in the mould with the normal reinforcement and the pulled tendons.
After the concrete has sufficiently hardened, the prestressing tendons are spliced and the stress is transferred to the member. Here the stress transfer is through the bond strength between the concrete and steel. This is called pre-tensioning.
In Post tensioned prestressed structures, the concrete member is the first cast with the conventional reinforcement and special ducts. After hardening, high strength steel tendons are introduced into the ducts and are prestressed and anchored to the ends of the member.
Here the stress transfer is through the bond strength and anchorage blocks of the members This is called post-tensioning. The post-tensioned slabs are mostly precast and are of various shapes. Post-tensioned slabs are widely used because of their ability to be cast in a shorter period of time.
Applications:
- Bridge decks
- Parking
- High rise buildings
- Retaining walls
- Sound walls
- Culverts
9. Light Weight Concrete
Light weight concrete is a special type of concrete used to reduce the self-weight of the structure. The reduction in self-weight can be achieved by any of the following methods
i) Light Weight Aggregate Concrete:
Using light weight aggregates like silica sand, pumice, sawdust, scoria, volcanic cinder blocks, volcanic slag, tuff, crushed stone, and synthetic aggregates like coke breeze, foamed slag, bloated clay, expanded perlite, thermocol beads, broken bricks etc.
ii) Aerated Concrete:
The concrete can be made light by increasing the air density inside to concrete from 300 kg/cu.m to 800 kg/cu.m. The air can be introduced by chemical reactions, using foam or chemicals like aluminium powder, hydrogen peroxide, and zinc compounds.
iii) No fines Concrete:
In this concrete, the self-weight is reduced by removing the fine aggregates in the concrete. No fines concrete is made up of cement, coarse aggregate, and water. The Aggregate to cement ratio is set between 6:1 and 10:1.
Application:
- In precast elements
- Bridge decks
- Long span structures
- Filling for floor and roof slabs
- Partition walls
10. Polymer Concrete
Polymer concrete is a special type of concrete that will reduce the pores in the member through the incorporation of polymers into it. The porosity in the concrete can be due to the presence of air voids, water voids, or voids in the gel structure.
There are four types of polymer concrete:
a. Polymer Impregnated Concrete:
In this type, conventional concrete is allowed to cure and harden. After this, the monomers such as styrene, acrylonitrile, thermoplastics are injected into the voids under high temperature and the voids are packed through polymerization.
b. Polymer Cement Concrete:
In this type of concrete, the monomers/polymers such as polyester styrene, epoxy styrene, etc., are added to the concrete mix during the mixing process itself.
c. Polymer Concrete:
In this type of concrete, instead of cement polymers are used as binders to reduce the porosity of the member. Polymers, aggregates, water, and coupling agents that improve the bond strength like silane are mixed together to form the polymer concrete. Due to the absence of cement, this concrete is not strong enough.
d. Partially impregnates and surface coated polymer concrete:
Just like the polymer impregnated concrete, the members are allowed to dry and then dipped in high temperature monomer solutions to pack the voids through polymerization.
Applications:
- Chemical industries
- Underwater constructions
- Marine works
- Desalination plants
- Sewage works
11. High Density Concrete
High-density concrete is a special type of concrete made up of cement, water, fine aggregate, coarse aggregate, and high-density aggregate.
The density of normal Plain cement concrete is 2400 kg/m3. For high-density concrete, the density ranges from 3360 kg/m3 to 3840 kg/m3.
The density of the concrete is increased by increasing the cement content, reducing voids, and using high-density aggregates like barite, magnetite, serpentine, limonite, goethite, etc.,
Applications:
- Power plants
- Coal plants
- Research institutes
12. High Performance Concrete
High-performance concrete is a special type of concrete made using cement, water, fine aggregate, coarse aggregate, mineral admixtures, and superplasticizers.
The mix design ratio of the high-performance concrete is designed in such a way that it performs well both structurally and in durability criteria.
The performance of the concrete can be improved by making the three phases of the concrete – the paste phase, transition phase, and aggregate phase stronger.
It can be done by increasing the cement content, restricting the water-cement ratio to not more than 0.3, using superplasticizers, mineral admixtures, and non-porous aggregates.
Applications:
- Power plants
- Chemical industries
- Coal plant
- Research Institutes
13. High Strength Concrete
High strength concrete is a special type of concrete that is made up of cement, water, fine aggregate, coarse aggregate, mineral admixtures, and superplasticizers.
Mineral admixtures like fly ash, ground granulated blast furnace slag, silica fume, rice husk ash have a high specific surface area which plays a major role in increasing the strength. High-strength concrete has a compressive strength of at least 70 MPa.
Applications:
High-strength concrete is used in the precast industry. The concrete has to be strong enough to withstand the huge amount of prestressing that will be transferred through the process.
14. Air Entrained Concrete
Air entrained concrete is a special type of concrete used made using cement, water, aggregates, and air-entraining agents. The air-entraining concrete can also be made using air-entraining cement. The need for air-entraining agents is prominent in cold-weather regions that are vulnerable to freeze-thaw cycles.
The liquid water penetrating into the cement structure under freezing temperatures will turn into solid ice. The volume occupied by the solid ice is greater than that of the liquid water thus increasing the internal pressure.
As a result, cracks will be formed to release the pressure. This is called as the freeze-thaw cycle. This can be avoided by using air-entraining agents like wood resins, hydrogen peroxide, aluminum powder, sulphonic acid, etc.,
These air-entraining agents will form artificial air pockets inside the mix. These artificial air pockets produced by the sir entraining agents can make up for the extra space needed by the formation of ice.
Air entraining admixtures can also be added to ordinary cement to achieve the same results. This increases the durability of the structure but obviously, the air pockets will reduce the strength of the concrete.
Applications:
• In cold-weather regions where the freeze-thaw cycle is common.
• In sulphate rich soils and water.
15. Self-compacting Concrete (SCC)
Self-compacting concrete is a special type of concrete made up of cement, fine aggregates, coarse aggregates, chemical admixtures to improve the workability, flowability, rheology, and mineral admixtures.
SCC is also known as zero slump concrete. It has high workability and does not require any extra compaction. It is used in congested reinforcements where it is quite complicated to achieve full compaction.
The flowability of the concrete can be achieved using viscosity modifying agents like sikaplast, retarders, air-entraining agents, very fine mineral admixtures, and superplasticizers.
Applications:
- In congested reinforcements like beam-column junctions.
- In places of heavy reinforcements.
- Places where compaction is not possible.
- Deep beams.
16. Shotcrete
Shotcrete is a special type of sprayed concrete where mortar or small aggregate concrete is sprayed at high velocities using compressed air to the place of interest. In shotcrete, a pre-mixed wet mortar or concrete mix is sprayed through a nozzle.
Applications:
- Repair works
- Slope stabilization
- Marine structures
- Tunnel construction
- Underground excavations
- Swimming pools
- Domes
- Retaining walls
- Mining
17. Guniting Concrete
Guniting is very similar to shotcrete but uses a dry mix. It is a method of spraying concrete on surfaces using compressed air. Unlike shotcrete, guniting uses a dry mix which will be uniformly mixed with water near the nozzle and discharged to the receiving surface. This process provides more bond strength than shotcrete.
Applications:
- Repair works
- Slope stabilization
- Marine structures
- Tunnel construction
- Underground excavations
- Swimming pools
- Domes
- Retaining walls
- Mining
18. Pumped Concrete
Pumped concrete is a special type of concrete that is suitable for pumping. Admixtures are added to improve the workability, flowability, and pumpability of the concrete.
Applications:
- Tall buildings
- Tunnels
- Underwater construction
19. Pervious Concrete
Pervious concrete is a special type of concrete that has high porosity and allows water to pass through it and recharge the groundwater. It is widely used in pavements where it can allow stormwater to pass through it.
In pervious concrete, the fine aggregates used are minimized or totally neglected and thus making it porous. The porous nature of the concrete demands high maintenance and regular cleaning.
Applications:
- Pavements
- Parking
- Light traffic areas
- Walkways
- Green houses
20. Smart Concrete
Smart concrete is a special type of concrete that can self-monitor its health. Smart concrete can be self-sensing, self-healing and/or self-adjusting.
Functional fillers such as carbon fibres, steel fibres, carbon nanotubes, nickel powder, etc., are added to the concrete to improves its ability to sense the stress, strain, and damage due to cracks.
Some concrete in addition to monitoring the health has the ability to heal themselves. These functional fillers should be well distributed inside the concrete to prevent any lump formation.
Applications:
- High rise buildings
- Regions prone to earth quakes
- Highways
- Bridges
- Air field pavements
- Dams
- Nuclear power plants
21. Stamped Concrete
Stamped concrete also called imprinted concrete or textured concrete is a special type of concrete used for ornamental purposes in floorings of patios, sidewalks, parking, greenhouses, gardens, pool decks, and interior flooring. Mineral pigments shall be added to the concrete to get the required colour.
The concrete of required color is laid and the surface is prepared for stamping. The stamping can be done using concrete stamps made of polyurethane. The stamping gives an embossed and classy look to the concrete which is often considered to be decorative.
22. Limecrete
Limecrete is a special type of concrete made using natural hydraulic lime, sharp sand, and glass fibres (optional). Limecrete makes the building energy efficient by improving its thermal performance.
The limecrete unlike conventional concrete will not be set in 24 hours. Limecrete is a hydraulic concrete using carbon dioxide in the air to harden and it takes time. It is more flexible than concrete. However, excess lime may hinder the breathing of people inside the building.
23. Asphalt Concrete
Asphalt concrete is widely used in pavement construction. It is made using aggregates, crushed stones, and asphalt. Asphalt is a bituminous material that acts as a binder in concrete.
It is used on normal roads, highways, airport roads, and parking lots. Asphalt is 100% recyclable and a widely recycled material in construction.
24. Bacterial Concrete
Bacterial concrete is also known as self-healing concrete has the ability to repair cracks and fissures by itself. This made adding special bacteria and calcium lactate to the concrete mix.
The most common bacterium is Bacillus Pasteruii. When cracks are formed, water seeps through the cracks and initiates the self-healing process.
In the presence of water, the bacteria germinate by feeding on the added calcium lactate converting it into calcium carbonate – limestone.
Limestone hardens over time and thus repairing the concrete by itself. With the help of bacterial concrete, the life span of the building can be increased to 200 years.
25. Smog Eating Concrete
Smog eating concrete is a recent development in concrete technology to fight against pollution in modern cities. It is made by adding a photocatalytic additive called Titanium dioxide to the concrete.
This titanium dioxide in the presence of sunlight gets activated and reacts with the pollutants in the atmosphere to neutralize them into harmless salts.
By doing so, it reduces the air pollution levels in the area surrounding the building. It can neutralize pollutants like Carbon dioxide, Nitrogen dioxide, and Sulphur dioxide.
Some other types of concrete are Sulphur impregnated concrete, Roller compacted concrete.
Also Read
16 Types Of Cement Used In Construction
Types Of Slabs Used In Construction
Types Of Bricks Used In Masonry Construction
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Very good information, thanks
Its best presentation of concrete types.
I interested more how to get the code /standards of aspect ratio. I need to do research on some fibers
So, can you offer me its location code of either IS or ACI? Example you explained that fibers can be added from 0.1 % to 0.3% and aspect ratio of 30 t0 150. please help me on this.