Types of Concrete and their Uses, Classification and Properties

Types of Concrete:

In construction there are different types of concrete and their uses classification and properties. The types of concrete are based on these given factors that is follow:

Its Density
Type of materials
Nature of condition

Table of Contents

1 Concrete:
- 1.1 Concrete Ingredient:
2 Types of Concrete:
3 Share this:

Concrete:

Concrete is universal building material are so pronounced that it has been used in different ways and different kinds than at present. Thousand years ago concrete was prepared from lime mortar mixed with gravels from 12000 to 6000 BC in Crete, Cyprus Greece and also in middle east. Concrete is very high resistance against fire and weather. It is used widely in the world because the materials used in concrete are cheapest and have marvelous properties like compressive strength etc. Concrete is a building material composed of cement, fine aggregate, coarse aggregate and water. It is used in slabs, columns, foundation, piles, retaining walls, ramp to build bridges, dams, buildings etc. concrete is prepared by hand for low projects. While for high projects the ready mix concrete is available in markets. Most of builders prepared concrete by themselves buy the cement bags mixed with coarse and fine aggregate plus water, using a wheelbarrow or other large containers. For fast construction or too much high projects builders used the ready mix concrete. Ready mix concrete is the concrete which is already prepared in containers in markets.

Concrete Ingredient:

The concrete is composed of different materials. The ingredient of concrete is given below:

Binding material
Fine aggregate
Coarse aggregate
Water
Admixture

Binding Material:

Binding material may be cement or lime. It is used to bind the materials such as fine aggregate and coarse aggregate. Mostly cement (ordinary Portland cement) is used to bind the materials for normal construction. Lime is also used to bind the materials and strong enough for ordinary construction but it is costly.

Fine Aggregate:

Fine aggregate is used in concrete for the purpose of fil the pores and spaces between coarse aggregate. Sand is mostly used as a fine aggregate in concrete.

The maximum size of sand should not be more than 4.7 mm and the grain size of fine aggregate is around 2 mm there are three types of sand which is given below:

Fine Sand
Medium Sand
Coarse Sand

The fineness modulus of sand should be not less than 2 and not more than 3.2. fineness modulus of different type of sand is given below:

S. No	Sand Type	Fineness Modulus (FM)
1	Fine Sand	2.20 to 2.60
2	Medium Sand	2.60 to 2.80
3	Coarse Sand	2.80 to 3.20

Coarse Aggregate:

Coarse aggregate is blend with fine aggregate (sand) to fill the gaps between them and interlock to each other. Coarse aggregate is used to get the desired strength because with the absence of coarse aggregate you can’t achieved demanded strength.

The size of coarse aggregate should not be less than 4.7 mm. in concrete the most common size of coarse aggregate is 40 mm and 20 mm is the most common size of coarse aggregate use in construction. The employed demand usual range of coarse aggregate is between 10 mm to 40 mm. there are different types of coarse aggregate based on size which is given below:

Fine gravel
Medium gravel
Coarse gravel
Cobbles
Boulders

The fineness modulus of coarse aggregate should not be less than 6. There is different fineness modulus for different sizes of coarse aggregate which is given below:

S. No	size of coarse aggregate (mm)	Fineness Modulus (FM)
1	20	6 to 7
2	40	7 to 7.5
3	75	7.5 to 8
4	150	8 to 8.5

Water:

Water is very essential material for concrete because it plays very important role in making bond of cement with aggregate without water cement is not able to mix with aggregate. Water should not be added more or less it must be added as per design of concrete. The water is added with ratio of cement in concrete is called water cement ratio.it is denoted by “W/C” generally water cement ratio is 0.40 to 0.60. when water cement ratio is below 0.40 the concrete will be hard. Its workability will be less and strength will be more. If water cement ratio is more than 0.60 its strength will be less but workability will be more high water cement ratio is directly proportional to the workability and inversely proportional to their strength.

There is different type of concrete ratios in which cement, fine aggregate and coarse aggregate are mixed but normally concrete is used in construction are:

M5 1:5:10

M7.5 1:4:8

M10 1:3:6

M15 1:2:4

M20 1:1.5:3

M25 1:1:2

The “M” means mixing of concrete number means its strength for example M20 means the concrete will bear the 20 N/mm² load safely.

Types of Concrete:

There is different type of Concrete is used in construction based on materials, condition, density, purposes and situation. The types of concrete are given below:

There are a lot of different types of concrete that is used in construction site the types of concrete are follow:

Normal Strength Concrete
Ready Mix Concrete
High Strength Concrete
Mass concrete
Ultra High Performance Concrete
Self – Consolidated Concrete
Pervious Concrete
Lime Crete
Asphalt Concrete
Glass Concrete
Rapid Strength Concrete
Shotcrete Concrete
High Performance Concrete
Vacuum Concrete
Light Weight Concrete
Pumped Concrete
Air entrained Concrete
High density Concrete
Polymer Concrete

Polymer cement Concrete
Polymer impregnated Concrete
Polymer Concrete

Precast Concrete
Pre stressed Concrete
Reinforcement Concrete
Plain cement Concrete
Stamped Concrete
Fly Ash concrete
Silica Fume Concrete
Ferro Cement Concrete.
Pre-packed Concrete.
Permeable Concrete
Smart Concrete
Volumetric Concrete
Decorative concrete
Rubberized Concrete
Geo polymer Concrete
Plum Concrete
Gypsum Concrete

1. Normal Strength Concrete:

Normal strength concrete is composed of normal cement, fine aggregate and coarse aggregate usually 1:2:4 mix is used in normal strength concrete. its initial setting time is about 30 minute and final setting time is 10 hours. The compressive strength of normal strength concrete is 20 Mpa (400PSI) to 40 Mpa. normal strength concrete is used in normal construction work where high or ultra-strength is not required. the water cement ratio in this type of concrete is normal should not more than 0.6. All properties of concrete in normal strength concrete is fine it means normal.

2. Ready Mix Concrete:

Some time it is difficult to prepare the concrete at site at this situation the concrete is mix in off site or order the concrete from industry / company. The water is added in very little amount and then work of mixing is done at the site. This ready mix concrete is used in congested area because to store the materials in congested area is very difficult and it is also used in road construction because to you can’t store the material in specific place or it is difficult to carry the materials with construction of road for this purpose the ready mix concrete is a good option.

There are two methods to prepare the ready mix concrete which is given below:

Transit Mixer:

It is the first type of ready mix concrete in which the concrete is prepared in central batching plant and then deliver to the site with the help of truck. The special truck is used in transit mixer that do not allow the concrete hardened before deliver to site. The dry materials are put in truck and then water is mix in concrete near the site.

3. High Strength Concrete

This type of concrete is called high strength concrete because the strength of this concrete is much more than normal concrete. The compressive strength of this type of concrete is about 900 kg/ cm². That strength is achieved in 28 days.

To achieve high strength or various type of strength is demanded then good aggregates should be used and ordinary Portland cement should be used more in quantity. The quantity of cement in high strength concrete is 450 to 550 kg / m³. In this type of concrete, the water cement ratio is low it means the water should be added in less quantity the water cement ratio in high strength concrete is 0.25 to 0.35 but sometimes 0.20 water cement can be used to increase the more strength because of low water cement ratio the chemical is used in concrete is called super plasticizer the quantity of this chemical in 1 m³ should be 5 to 15 liter and also silica fume is used in high strength concrete. These silica fumes are used to fill the voids and concrete will be strong more. fly ash is also used in this type of concrete. To prepare the concrete like this is very heavy and strong. The size of fine and coarse aggregate should be selected with good grading then concrete will be more durable and strong.

4. Mass Concrete

When concrete is hardening during hydration process the temperature is increasing if the temperature is not same to the exterior and interior surface of concrete then cracks will be formed if the section of concrete is large then it will be very dangerous that concrete work in which cracks are formed because of variation in temperature is called mass concrete. In heavy construction like buildings, ports, dams, airports, bridges etc. this cracks can form because in large section the temperature between exterior and interior surface of concrete is very different. The effect of exterior temperature is more because of exterior temperature the concrete surface is easily and quickly cold or warm. The variation in temperature can cause the expansion, contraction and shrinkage at the result of this stress is develop. If that stress is more than the strength of concrete, then cracks will be formed. From prevention of cracks During mass concrete work the exterior and interior surface of concrete should be reduce for this purpose the paint is use or cover it with plastic or other materials.

5. Ultra High Performance Concrete:

The concrete having compressive strength more than 150 Mpa in which high strength steel fibers are added with cement, fine aggregate and fly ash is also added. The water cement ratio is kept very low that is less 0.25. this type of concrete is very strong and durable because others three reason which is given:

low water cement ratio that is less than 0.2
Packing density of Ultra High Performance Concrete. Ultrafine particles such as cement, quartz powder, and silica fume are combined in an extremely tight way.
Pozzolanic material such as silica fume reacts with CH that forming additional calcium silicate hydrate to achieve high compressive strength.

The workability of ultra high performance concrete is low because of low water cement ratio. The value of slump is also low.

6. Self – Consolidated Concrete:

Self consolidated concrete is also called self compacted concrete. This type of concrete has a low yield stress, high workability and high deformability, good segregation resistance, good viscosity. Self consolidated concrete do not require compaction without compaction it can set. self compacted concrete is used in heavy reinforced section places where vibrators can’t be use for compaction and in complex shapes of shuttering that may be impossible to cast.

Self compacted concrete was intended in 1986 by Prof. Okamura at Kochi University, Japan, at this time the skilled labor was in limited and there was too much difficulties in concrete technology. Self consolidated concrete was firstly used in North America in this concrete binder is use high in quantity as well as high amount of chemicals admixtures, usually superplasticizer to increase flow ability and stability also decrease the viscosity. Mostly this type of concrete is used in repair works and for casting concrete in restricted areas.

7. Pervious Concrete:

It is the type of concrete in which there is a high porosity. Pervious concrete is prepared from a mixture of cement, fine aggregate, coarse aggregate and water.it is used as a porous medium that allows water to pass through and reach the underlying soil. The benefit of this concrete is to reduces runoff from a site while recharging groundwater levels. It is also used in feasible construction, sidewalks, parking areas, and greenhouses.

pervious concrete gives the property of water absorption. pervious concrete is prepared from a mixture of cement, water and coarse aggregates just like other concretes Some pavements is constructed from pervious concrete that can allow 2 to 5 gallons of water per minute, it can be good structure to control storm water drainage.

The strength of pervious concrete is not good because of porosity. There is a lot voids in aggregate and gaps between them that’s why pervious concrete is not used in heavy construction work. The compressive strength of pervious concrete is between 3.5 Mpa to 28 Mpa. Mostly compressive strength of 17 Mpa of pervious concrete is used.

8. Lime Crete:

. Lime Crete is also called Roman concrete or lime concrete it is developed in the 1800s by Dr, John E. Park. In this type of concrete, the lime is used as a binding material with fine aggregate and coarse aggregate. Before the development of cement, the lime was use as binding material but today lime Crete is using in foundation, floors, terrace and domes etc.it is renewable also offers environmental as well as health benefits.

The setting time of Lime Crete is slightly slow and absorbs carbon dioxide during the drying process. The Compression of lime Crete is high to serve as a floor slab material, and also strength can be improved by adding fibers, increasing the lime content. If the lime content is mixed more than it can compromise breathability.

9. Asphalt Concrete:

It is also called asphalt, blacktop, or pavement and tarmac or bitumen, macadam or rolled asphalt in different countries. the asphalt concrete is developed in 1800s and when the use of asphalt is grow the production or market of automobile industry is also expanding. Nowadays, there is a lot of development in asphalt technology. Today, highly advanced machinery and techniques are used to construct asphalt pavements.

The density of asphalt is 741 kg / m³ or 45 lb / ft³. It means in one cubic meter the weight of asphalt is 741 kilograms or in one cubic foot the weight of asphalt is 45 kilograms.

There are three following different types of asphalt concrete available:

Hot Mix Asphalt

It is prepared at high temperature between 150°C and 200°C. Based on the use, there are different mixtures of hot mix asphalt that can be prepared such as porous asphalt, asphalt, double layered porous asphalt etc.

Warm Mix Asphalt

In this type of asphalt concrete it is prepared at 20°C to 40°C of temperatures. The temperature is low even during the paving operations, safety for the working volunteer and road should be open quickly for the use.

Cold Mix Asphalt

This type of asphalt is used for roads with lighter vehicle. Cold mix asphalt production doesn’t need heat. it makes use of a specific bitumen emulsion. This emulsion burst at the time of compaction or mixing and coats the aggregate. after time, the coating increases the strength of asphalt.

10.Glass concrete:

Glass is made up from sand because sand is composed of silica typically glass is made up from silica. Glass is used in packaging (bottles for drink, jars or plates for food, flacon for cosmetics and pharmaceuticals) tableware (drinking glasses, bowls, cups etc.) housing and buildings (windows, facades, insulation and reinforcement structures).

When glass is mixed with concrete it forms glass concrete it is also known as glass fiber reinforce concrete (GFRC). It is firstly used in Russia glass concrete improves the aesthetic appeal of surfaces provide long term strength and thermal insulation.

Glass powder may be wont to replace Portland cement, mostly at a 0% to 25% replacement by weight. The Compressive strengths of glass concrete (0% to 25% glass replacement) at various ages. By the replacement of waste glass (0% to 20%) by the weight of cement give 35 Mpa at 28 days but the compressive strength for 25% addition of waste glass was slightly lower. With the addition of glass, waste glass concretes with 10, 15 and 20% glass addition give high compressive strengths and 10% of glass replacement gave optimum result but 25% of glass replacement gave a little bit lower compressive strength. The Addition of waste glass about 10% by volume increased the tensile strength of concrete.

The manufacturing of cement is the main sources for carbon dioxide emission. Waste glass is used in concrete as a Portland cement replacement not only helps the environment by reducing the carbon dioxide emission but it can also reduce the amount of waste glass.

Uses of Glass Concrete

The Uses of this type of concrete is very limited because of abrasion and impact forces they suffer damage and loss of strength at the time of movement of aggregates in mixer.

Many building wall panels made of glass concrete in Europe and united states. it has also been used for repair works and for industrial floors in United states of America

Applications of Glass Concrete

The applications of glass concrete in following construction works:

It is used in Building renovation works
Glass concrete is used in Water and drainage works
It is good to use in Bridge and tunnel lining panels
It is used in Permanent formwork method of construction.
Architectural cladding
Acoustic barriers and screens

11.Rapid Strength Concrete:

In this type of concrete, it gets strength very quickly. Rapid strength concretes can achieve strength with few hours once its manufacture. Therefore, the formwork is removed very quickly and the construction of building is roofed very fast. Rapid strength concrete is used in the road repairs, and they will be open for reused after some hours. This concrete gets strength 3000 psi in just 2 hours. In rapid strength concrete mostly Portland cement is use and the water cement ratio is 0.3.

To achieve compressive strength more than 17 Mpa and flexural strength more than three 3 Mpa following method should be done

For one hour or more than one-hour rapid hardening cement should be use.
For two or more than two-hours Type III Portland cement is used plus accelerator.

Rapid strength concrete is used in the construction for the solution of to minimize the trouble of public peoples by construction work because rapid strength concrete achieved strength quickly and can open the any type of structure to peoples for the purpose of use. The slump value of this type of concrete is very low about to 4 to 8 inch and also the workability of rapid hardening cement is low.

For lean concrete base the compressive strength of rapid hardening concrete should be minimum 5 Mpa or 721 Psi, rapid hardening cement is used in mix. The admixture is high range water reduce set controlling admixture (HRWR; SC) and water cement ratio should be 0.5 to 0.6. the curing time after completion of work should be minimum 1 hour.

pavement course to flexural strength of rapid hardening concrete minimum 2.8 Mpa or 400 Psi, rapid hardening cement should be used in mix. The admixture is high range water reduce set controlling admixture (HRWR; SC) and water cement ratio should be 0.40 to 0.45. the curing time after completion of work should be minimum 1 hour. While for flexural strength of rapid hardening concrete minimum 3.8 Mpa or 550 Psi, rapid hardening cement should be used in mix. The admixture is high range water reduce set controlling admixture (HRWR; SC) and water cement ratio should be 0.35 to 0.40. the curing time after completion of work should be minimum 1.5 hour.

12. Shot Crete Concrete:

This type of concrete is prepared same as other concrete, but the difference is that they are placed differently. Shot Crete concrete are placed with the help of higher air pressure by nozzles. Shot Crete concrete is made from the mixture of cement, aggregate and water prayed through nozzle Fiber and silica fume is also added to shotcrete concrete to improve the property of mixture. The size of coarse aggregate in mix should not be more than 10 mm Shotcrete concrete is good for thin portion and high areas. If the materials is mix correctly in Shotcrete concrete it will develop high strength, low water absorption, and low permeability if mixed. While if shotcrete concrete is applying incorrectly it will make a weak concrete surface, chemical attack easily the result will reduce the durability of the structure

Shotcrete machines are available that is used to control the full process and with the help of these machine it can make and place very fast and easy. There are also Manual and mechanical methods are used for the wet spraying process but mostly wet sprayed concrete is used by shot Crete machine. If the out and cross section of spray is high, then work should be done by machines. In wet mixes The Concrete spraying systems with duplex pumps are mostly used.

The advantages of this technique is that the compaction and placing of concrete will be done at the same time. short Crete also known as gunite or sprayed concrete. Typically, Shotcrete is used in tunnel walls, subways, mines and vehicle tunnels. The fire resistant shotcrete intended in Norway and it is used in the Marmaray tunnel in Istanbul turkey.

To prepared shot Crete concrete the skilled labor worker is required to mix the materials precisely and add the quantity of water in a correct way to get the good viscosity for both surfaces vertical and horizontal.

Shot Crete was discovered in 1907 by American taxidermist named carl Akeley. he repairs the failure structure in Chicago. First he shot the dry material out of a pipe with compressed air and then inject the water at the nozzle. In 1911, he invents “cement gun”, the equipment used, and “gunite”, the material that was produced.

The compressive strength of shot Crete is same as normal concrete about 28 Mpa or 4000 Psi. the water cement ratio of shot Crete is 0.40 to 0.50. the water should be added more but not more than usual because it will be affect the strength. The workability of this type of concrete is more for the use of to flow easily in shot pipes.

There are two methods of short Crete to prepare first is dry mix short Crete and wet mix short Crete. These two methods are given below:

Dry Mix Short Crete:

In this method the cement is mixed with aggregate in dry condition and pass it to pneumatic gun. This gun is used for continues flow of the mix from the pipe to the nozzle. This nozzle is connected with a water ring that injects water to mix uniformly.

Wet Mix Shot Crete:

In this method the cement is mixed with aggregate and also water is added after that mixture is deliver to delivery equipment such as a concrete pump. Then the mixture will be pumped through a pipe to the nozzle. At last Additional air should be added at the nozzle for the purpose of to increase velocity of the discharging materials.

13.High performance concrete:

High performance concrete is the new type of concrete in which the performance of this type of concrete is more than normal concrete. The strength and durability of high performance concrete is high but not all high performance concrete strength is high. These properties of this type of concrete is good which is given below:

It can easily placed
No segregation with Compaction
Get strength quickly
Mechanical properties are good
Good Permeability
Density
Hydration
Toughness
Volume stability
Structure have Long life in terrible environments

The compressive strength of high performance concrete is 70 to 80 Mpa. The water cement ratio should be not more than 0.35. it is prepared from good quality of aggregate and high amount of cement about 450 to 50 kilogram per one cubic meter. The aggregate should be taken very carefully because poor quality of aggregate affects the concrete very badly. The silica fume is also added with high performance concrete about (5 to 15%) by the weight or volume of cement. To achieve the high performance, the water cement ratio should be use (0.20% to 0.35%). Super plasticizer should be use 5 to 15 liter per cubic meter.

14.Vacuum Concrete:

This type of concrete is prepared in which too much amount of water is removed for improving concrete strength. With the help of vacuum mats. The water can be removed simply to connect with vacuum pump. Vacuum concrete is used in factory floors, parking lots, bridges and its deck slabs etc. The magnitude of applied vacuum is usually about 0.08 MPa and the amount of water is decreased 20 to 25%. The decrease is effective up to a depth of approximately 100 to 150 mm only.

In this concrete water content is high in mixing process to improve the workability and enable it to be handled, placed into complex molds or in formwork where reinforcement is more.
Vacuum concrete was first intended by Billner in US in 1935 AD.
The strength can be control and other properties of concrete by reducing the content of water before setting.
The water cement ratio is less than 0.38 but mostly it is used more than 0.38 for good workability.

Advantages of Vacuum Concrete:

The advantages of vacuum concrete are given below:

Vacuum concrete improve the compressive strength.
The density of this concrete is high
The final strength of vacuum concrete is increase up to 25 %
It improves the tensile strength
Vacuum concrete reduce the shrinkage
It increases the durability
This technique decreases the permeability
Vacuum concrete make the resistance against impact and also abrasion

Disadvantages of Vacuum Concrete:

The disadvantage of vacuum concrete is given below:

Initial cost of vacuum concrete is higher
In vacuum concrete it required skilled labor
It need specific equipment and machinery
Vacuum concrete need power consumption

Equipment Use in Vacuum Concrete:

The equipment and machinery that is use in this technique (vacuum concrete) are follow:

Vacuum pump
Water separator
Filtering pad
Screed board vibrator

Vacuum Pump:

It is a small pump the power of vacuum pump is 5 to 10 HP (horse power). This pump is very strong to pump used for to pump the water.

Water Separator:

Water is pumped by vacuum pump and it store in water separator. Water separator is used to store the water.

Filtering Pad:

In filtering pad, the mats are placed above. It is used to prevent the removal of cement with water. The minimum dimension filtering pad is about 90 x 60 cm. filtering consist of following components:

Rigid backing sheet
Expanded metal
Wire gauge

15. Light Weight Concrete:

The lightweight concrete has been invented early in 1900s and it is firstly used in United States. It is the type of concrete in which the density of concrete is lower than other type of concrete. The density of light weight concrete is 320 to 1920 Kg / m³.it is prepared from mixing the cement with light weight coarse aggregate and normal weight of fine aggregate some time light weight fine aggregate can be added.

Types of Light Weight Concrete:

There are three main type of light weight concrete that is given below:

Light weight aggregate
Aerated concrete
No fines concrete

Light Weight Aggregate Concrete:

It is first type of light weight concrete in which weight of aggregates is lower than 1120 kg/m³. Lightweight aggregates are:

Natural materials such as shales, Scoria, Sawdust, Rice husk clays, pumice, diatomite, volcanic cinders and slates
Artificial materials or by products that is iron blast furnace slag, clay, sintered fly ash, expanded shale Artificial cinders, Coke breeze, Foamed slag, Bloated clay, slate, Exfoliated vermiculite, Expanded perlite, Thermo cole beads.

The Property of this type of concrete is depend on different type of lightweight aggregate in the concrete. The compressive strength of Structural lightweight aggregates used in concrete is more than 35 MPa while a compressive strength of limited number of lightweight aggregates used in concrete from 48 to 70 Mpa.

Aerated concrete:

It is second type of lightweight concrete. Aerated concrete is also called cellular concrete. There are two main types according to the method of manufacturing.

foamed concrete (Non-Auto calved Aerated Concrete (NAAC):

this concrete is also known as NAAC because it is non-auto calved aerated concrete. it is manufactured by injecting preformed foam or adding air entraining admixture called as foaming agent that is mix into a base mix of cement paste or mortar.

Autoclaved aerated concrete (AAC):

The Autoclaved aerated concrete is manufactured by adding the amount of aluminum powder and other additives into slurry of ground high silica sand, cement or lime and water.

No fines concrete:

It is type of light weight concrete it is prepared from the mixing of cement, coarse aggregate and water but sand or fine aggregate is not use. After mixing water with the materials such as cement and coarse aggregates. The coarse aggregate particle will have covered with a layer of cement paste up to about 1.3 mm thick. Density of this type of concrete is depending on the type grading of the aggregate and also on its grading. The coarse aggregate size should not be more than 75 mm but typically the size of coarse aggregate that is use from 10 to 20 mm. The types of coarse aggregate used in no fine concrete should be gravel or crushed aggregate but it can be without sharp edges which increase the likelihood of local crushing under load. This concrete is made from carefully controlled amounts of water and cement that is used to prepare a cement paste that forms a thick coating around coarse aggregate.

Advantages of no fines concrete:

The advantages of no fines concrete are given below:

No fine concrete density is low
The cost of this concrete is low due to lower amount of cement.
The thermal conductivity is good
The drying shrinkage of no fine concrete is relatively low
There is No segregation if it can discharge from high level.
Because of low hydrostatic pressure there is no capillary movement of water.
No fine concrete has good insulating property than normal concrete because of large voids.

Based on strength:

According to American concrete institute 213 (ACI 213, 2001). There are three various type of lightweight concrete based on strength. The types of light weight concrete in term of strength are given below:

Low density concrete:

the strength of low density concrete is 0.7 to 2.0 Mpa. while the density of low density concrete is ranges from 300 to 800 kg/m³

Moderate Strength Concrete:

In this type of light weight concrete the strength of moderate strength concrete is 7 to 14 Mpa. while density of this type of concrete is ranges from 800 to 1350 kg/m³

Structural Concrete:

Structural concrete is type of light weight concrete in which the strength is ranges from 17 to 63 Mpa. while density of this type of concrete is ranges from 1350 to 1920 kg/m³

Use of Light Weight Concrete:

The use of lightweight concrete is in following places:

Light weight concrete is mostly used in Multi story buildings
It is used in long span bridges
In large structures for example Mindless Building Young & Darwin etc.

Advantages of Light Weight Concrete:

The advantages of light weight concrete are given below:

Low density of lightweight concrete in construction,
low thermal conductivity.
low shrinkage
high heat resistance
Reduction in dead load
lower transportation cost because of its weight
Faster building rate example of faster building rate is Wongkeo, Thongsanitgarn, Pimraksa, & Chaipanich in 2012.
Local industrial wastes can be used as a material in light weight concrete.
The use of lightweight concrete reduces the cost up to 30 to 40 percent.
The fire resistance of light weight concrete is more than normal concrete.
The thermal expansion of light weight concrete is less than normal concrete.
The sound absorption of lightweight concrete is good

16. Pumped concrete:

It is the type of concrete in which is the concrete is transported to heights with the help of pumping by concrete pumps. This type of concrete is used where large amount of concrete work is involved at greater height or transporting of concrete is not easy to do.

Concrete pumps is used from more than 50 years. Nowadays greater amount of concrete is transported with the help of pumping through pipelines. The concrete pump is invented In 1927 by two German engineers Max Giese and Fritz Hull. First they pump the concrete through pipes. Max Giese and Fritz Hull pumped the concrete to a height of 38 meters (125 ft.) and a distance of 120 meters (130 yard).

Types of concrete pumps:

There are two main types of concrete pumps that is used for transporting. The types of concrete pumps are given below:

Direct acting concrete pumps
Squeeze type concrete pumps

17. Air Entrained Concrete:

Air entrained is the type of concrete in which air is entrained for an amount of 3% to 6% of the concrete. It is done by the addition of foams or gas, foaming agents. The examples of air entraining agents are alcohols, fatty acids and resins alkali salts from resin acids, sulphonated resin acids, alkali sulphonates, alkyl sulphonates, alkylarene sulphonates etc.

In this type of concrete it contains microscopic air bubbles that range in size from a few thousandths of an inch in diameter to a few hundredths, and typically air bubble is compose between 4 to 7% of the total Volume of the concrete.

when it freezes air bubbles create chambers for water, thereby reduce internal pressure on the concrete. Air entrained concrete is manufactured by establish air entraining agents after concrete is mixed or it can be prepared by using air entraining portland cement.

Air entrained concrete has high resistant against:

Abrasion
Scaling / ascend or mount
collapse due to freezing and thawing or defrost

air entrained concrete is highly porous, that having small capillaries because of hydration reaction for which the evaporation of water is required. A water cement ratio (w/c) of in this concrete is used about 0.38 (this means 19 liters of water for every one bag of cement) is required for all the cement particles to hydrate. Usually Water is used to make the plastic concrete more workable, low slump value, easily flowing, less viscous. The water cement ratio in Most of concrete is used 0.40 to 0.60, which means there is essential excess water that will not react with cement. After some time, the extra water is evaporating it created little pores in concrete. At the end water of environment can fill these voids. At the time of freeze thawing cycles, the water involves in these pores it expands and creates stresses which create tiny cracks. These cracks permit or absorb more water into the concrete and then cracks extend. Because of this concrete spalls and fail. The failure of concrete or RCC is mostly often because of this cycle, in which moisture is reaching to the reinforcing bar. Steel or bar swell or stretch when it rusts, and these forces produce more cracks allowing in more water.

Air entraining concrete was firstly intended in the 1930s and it is most advance concrete, especially in freezing temperatures. The air is entrained in this concrete. The bubbles contribute to workability by acting as a sort of emollient or smooth for all the aggregates and large size particles in a mix of concrete.

18. High Density Concrete:

The density of this concrete is 3360 kg/m³ to 3840 kg/m³, whereas the density of ordinary concrete is 2400 kg/m³ and density of light weight concrete is approximately 1900 kg/m³. While density normal concrete about 2400 kg/m³. Thus the density of high density concrete is approximately 50% more than normal concrete. However, this concrete can be produced of density up to 5150 kg/m³ when using iron, fine aggregate and coarse aggregate.

The admixture is used for reducing of water is lignosulfonic acid, carboxylic acids the advantage of water reducing admixture in high density concrete is given below:
It Increase the workability
water reducing admixture low the requirement of water.
It is used to Reduce water content requirement
water reducing admixture is good for high early density

Advantages of High Density Concrete:

Increased density up to 4 tons per m³
High density concrete low the risk for thermal cracking
It saves Spacing
High density concrete low the Cost
It completes the project Faster.
Resistant against severe weather
It Can be use everywhere in all construction practices
It is good for pre cast blocks
High density radiation shielding
It is used for lowering noise and vibration.

Uses of High Density Concrete:

The use of high density concrete is given below:

High density concrete is used heavy Gravity based structures
It is used in Ballasting for floating wind construction.
Good for Coastal and protection of erosion
Anchors for wave and tidal devices
It is used for concrete weight coating for pipelines.
High density concrete is used in concrete anchoring.

19. Polymer Concrete:

The polymer is mixed with the binding material such as cement and aggregates. polymer concrete also known as Polymer Portland cement concrete (PPCC) or (LMC) latex modified concrete.

Advantages of Polymer Concrete:

The advantages of polymer concrete are given below:
Polymer concrete require low energy.
Reduce labor costs.
Polymer concrete gives higher properties.

it is not like conventional concrete, although in polymer concrete same types of material is use. This type of concrete is also used for construction works in the same manner, but some characteristics is achieved by polymer material that makes the concrete safer or more durable than normal concrete. Polymer concrete can be more expensive than regular concrete.

In aggregate mixture that uses some type of epoxy binder in polymer concrete for the purpose of to cure and harden into place. The epoxy binder is polyester, vinyl ester some times normal epoxy mixture can also use, but polymer concrete can be made with many kinds of polymer resins that let the concrete to be poured and after that it hardened. Polymer concrete is cure with the help of chemical reaction by polymer material. Such as normal concrete that compose of water, fine aggregate and gravel / coarse aggregate crushed stone.

Polymer Cement Concrete:

To prepare the polymer cement concrete it require to mix Portland cement and pre polymer or monomer of a distributed polymer is include. This combination makes a polymer network in situ at the time of curing process of the concrete. The use of vinyl monomers can obstruct and affect the hydration process or can become degraded. So the use of Pre Polymers is good and more effective as perform the function required. If you want to improve the mechanical properties of the Polymer cement concrete, these pre polymers should be added in higher ratio. When the mechanical properties of concrete are based on the adding of a polymer then special care and attention is taken while if latex is adding. The emulsion is applied to increases the lubrication of the mix. Thus only less amount of water is required for workability of the mix.

Polymer Impregnated Concrete

It is the type of polymer concrete. it consists of polymers or epoxies that are used to convey particular properties of concrete. different application of polymers and their properties is discussed.

Use of Polymer:

There is various use of polymer in concrete that is given below:

It improves the strength and durability of concrete
polymer increase the chemical resistance and the water proof property of concrete.
The workability of concrete can be adjusting or improve based on the required specifications
The bond between old and new casted concrete can be modify
Urethanes are prepared by the reaction of polyols with the isocyanates
Acrylics are esters of acrylic and meth acrylic acids
The type of synthetic fibers are Epoxies
Styrene Butadiene Resins are synthetic rubbers in the solution

20. Precast Concrete

It is a construction manufactured product that is prepared by casting concrete in a mold which is then cured in a good environment after that it is transported to the site of construction and lifted in to place. While conventional concrete is prepared and then poured into site certain forms and at last cured on site. Precast stone is different from precast concrete. In precast concrete fine aggregate is using in the mixture. when the product is prepared its appearance is just like natural rock or stone. expand polystyrene is also used to precast wall panels. The density of this is low or it is lightweight and good against thermal resistance.

It is used within exterior and also interior walls. By producing precast concrete in a good environment or plant, the precast concrete must be cure and closely monitored by plant employees. there are many advantages of precast concrete over on site casting concrete. Precast concrete preparation can be performed on the level of ground, that helps with safety everywhere in a project. To prepared the concrete There is greater control on quality of material and number of labors in a plant compared to an onsite construction. The molds which is used in a plant it can be use again and again hundreds to thousands of times before they have to be replaced, pre cast construction is cheaper than onsite construction when looking at the cost per unit of formwork. There are various types of precast concrete. It is differing in size, use, purpose and cost.

Use of Precast Concrete:

The use of precast concrete is follow:

Precast panels are used to clothed all or part of a building elevationor for landscaping free standing walls is used,
It is used for sound proffing
It is used Reducing moisture
Precast concrete can be used for security walls
several structural elements can be pre stressed concrete such as Storm water drainage, pipes of sewer and tunnels they uses precast concrete.

Types of Precast Wall Panel:

There are four main types of precast wall panel that is given below

sandwich,
plastered sandwich,
inner layer
cladding panels

There is a lot of surface finishes are available. The most commonly available cement is white or grey. There are also Different colors of cement that can be added with pigments or paints. The aggregate size and color also affect the aspects and texture of concrete surfaces. Molds have an effect on the look of precast concrete surface. The mold can be made of timber, steel, plastic, rubber, fiber or glass, each of them give a unique finish.

The fire resistance and sound proofing properties of precast concrete make them ideal for a different building applications. In precast concrete the decrease moisture and making a good energy environment these are other two convincing factors when constructing a precast concrete building.

In construction the members of structure are already prepared. These members will just fix with the help of heavy machinery is called precast structure. Precast members are also prepared from the cement. Some members are prepared from the cement mortar. Cement mortar is the mixture of cement, sand and water respectively. While some members are prepared from concrete. Concrete is mixture of cement, fine aggregate, coarse aggregate and water. Precast concrete pipes are widely used as a drain, pipes under culverts, sewage purpose etc.

Advantages of Precast Concrete:

For residential and commercial construction, engineers can easily do planning and design when using precast concrete in construction. Precast concrete take place on site completely customized and ready for fast installation. To select precast concrete, you can faster your project and save the cost that appear from using concrete that are precast offsite. the convenience and workflow to include versatility, control, efficiency and sustainability all of which come together to make a better precast concrete.

1. Versatility:

We already discussed versatility of precast concrete but highlight it the versatility once again, as it the advantage of this type of concrete construction. The ability of concrete to shape, colors, texture and size you want is a big part of the reason it has implications in such a wide range of industries and uses. While some of people think that precast concrete has a lack of versatility, the opposite is true.

2. Controlled Environment:

This type of concrete is prepared in a controlled environment, which stop the chance of outside variables such as weather, obstruct with the quality or time schedule of production. You have full control over the weather to confirm that all precast concrete is cured ordinary in ideal conditions. Since you have gain to these ideal conditions, you can be sure that preparing of these concrete materials will be on time, as weather slow down for placing on site become a thing of the past.

3. Efficiency:

Efficiency comes as a result of the controlled manufacturing environment. When you are capable to prepare precast concrete all year long in a plant. it speeds up the overall construction process. Suddenly you don’t need to care about scheduling placing concrete on site at the time which weather could delay your whole project.

This process is now so well organized that you could even get the precast materials prepared already and store them until you need to get them in place on site. Because of assembly line techniques precast concrete save cost and time that need less number of labor and it also decrease the stress of coordinating on site skilled labor and logistics.

4. Sustainability:

To prepare the Precast concrete it is a durable process. actually many durable buildings they use precast concrete to get LEED certification the reason is:

Concrete is composed of natural aggregates, shingles, sand, stone and water.
Water is used in the process of preparing concrete is recycled.
This type of concrete is used for long term energy savings thermal mass absorbs and releases heat slowly.
Factory environments greatly decrease waste from bracing and formwork, excessive concrete, packaging and debris that builds up on site when you cast in place.
The Precast structures use less ingredients than concrete cast on site.
Factory environments are good for employees than construction sites because safety hazards, noise and air quality can be controlled.
Precast concrete materials are available locally, with aggregates mined a small distance from manufacturing that cuts down on drag trips

Disadvantages of Precast Concrete:

There are some disadvantages of precast concrete are that is given below:

Each piece is construct separately, the construction system is not monolithic or regular like concrete The joints between members make structural disconnectedness. The forces of the structure will go through these joints, so it should be design to transfer these forces safely. The precast concrete can be also used for non-structural members too.
When the building is made of these precast members the joints between all members should be sealed with special sealants to build them water proff.
All precast member is normally large and heavy. it means that heavy machinery are required to lift hem up or in its right position; these machinery are required to control the entire building . Since there will be two or three machinery present at site, the time taken by the machinery to lift up a members and move it to its final position becomes censorious in decide the building schedule

21. Pre Stressed Concrete:

It is the type of concrete in which internal stresses are produce without any external loads to better its performance. The internal stresses produced in the concrete that is used to resist the stresses coming from the external load.

According to AASHTO (American Association of State Highway and Transportation Officials), high strength 7 wire PC strand, steel wire or alloys of grades and type (recommended by designer) should be used in pre stressed concrete. Also, stronger concrete is required in pre stressed than conventional RC. usually, min 28 days. The cylinder strength of more than 5000 psi concrete should be used. if the concrete is not strong enough, it can be cracked or failed when it is stressed by tendons. Also high compressive strength provides higher resistance to tension and shear and so it is good for pre stressed concrete.

Advantages of Pre Stressed Concrete:

The Advantages of Pre Stressed Concrete is given below:

It is less subjected to shrinkage crack.
It has a higher modulus of elasticity
smaller creep strain
loss of pre stressing is small.

Types of Pre Stressed Concrete:

There are two Types of pre stressing concrete:

Pre tensioning
Post Tensioning

1. Pre Tensioning:

In the pre tensioning, the stress is produced by initially tensioning the tendons. These are wires or strands that are tensioned from the end anchorages. After this, the concrete placing is done. Once concrete has hardened, the end anchorages are released. This releasing transfers the pre stress force to the concrete. The bond between the concrete and the tendons make possible this stress transfer.

The tendons that are extending at the ends are cut and it will get a finished look. In order to induce pre stress force in the pre tensioning, the number of tendons and wires are used. This arrangement makes the bond and stress transfer possible.

2. Post Tensioning:

The procedure in post tensioning is represented. Here, after the beam is cast the steel is pre stressed, cured and get strength to take the pre stress. Within the surface, the concrete is place. For the passage of steel cables, ducts are establishing in the concrete.

Once the concrete hardens fully, the tendons are tensioned. The One end of the tendon is anchored and the other end is tensioned. In a few cases, the tensioning can be executing from each side and anchored at a subsequent time. When the pre stressing is done, there is gap between the tendons and the duct.

It is very important to mention that we did not need to make these beams stronger. The steel and concrete both of have the same strength as they would in the absence of pre stressing the steel. But, the serviceability of member should be increase by decreasing the amount of deflection under load. Certainly, none of these examples usually failed because of the reinforcement. This type of concrete is used in all kinds of structures from bridges to buildings to silos and tanks. It is a great way to decrease cracking and take full benefit of the good strength of reinforced concrete.

22. Reinforcement Concrete:

The concrete in which steel is place in such a manner that the two materials are used to resist forces. In structure of concrete The reinforcing steel, rods, bars, or mesh absorbs the tensile, shear, and sometimes the compressive stresses. While Plain concrete does not resist easily tensile and shear stresses caused by wind, earthquakes, vibrations and other forces. In reinforcement cement concrete (RCC), the tensile strength of steel and compressive strength of concrete work together to permit the member to bear these stresses over reasonable spans or length. The creation of reinforced cement concrete in the 19th century restructure the industry of construction, and concrete became one of the world’s most common building materials. This concrete is also called reinforced cement concrete or RCC this concrete is prepared from different materials such as cement, fine aggregate, coarse aggregate and steel. In reinforcement cement concrete. the concrete is low in tensile strength and also ductility while reinforcement bar or steel is high in tensile strength or ductility. The steel reinforcing bars or rebar, steel, mesh or rods is normally immersed passively in the concrete before the concrete is hardened.

History of Reinforced Concrete:

The Francois coignet was the French industrialists who use iron reinforced concrete as a technique for constructing building structures. In 1853, François Coignet construct the first iron reinforced concrete structure, a four story house in the Paris, France. When François Coignet’s intend the reinforce concrete he say that I did not work for means of adding strength to the concrete but I prepare this concrete for keeping walls in monolithic from overturning. In 1854, English builder William B. Wilkinson construct the roof and floors from reinforced concrete in the two story house.

In 1800s the Roman Empire used the reinforced in concrete Before 1877 in construction but at this time it was not proven scientific technology. The Thaddeus Hyatt he was the American inventor who published a report in which he has done Some Experiments to combine iron with Portland Cement Concrete as a Building Material.

The first skyscrapers building is constructed with reinforced concrete in 1904. it was the 16 story building named Ingalls building in Cincinnati united states of America.

On 18^th April, 1906 an earth quake having magnitude 7.8 affect the San Francisco in US. This earthquake destroyed much of the city and killed thousands of people. The use of reinforced cement concrete after the earthquake was highly boost and famous in the construction of united states industries because of its highly resistive against seismic loads relative to masonry.

Uses of Reinforced Concrete:

The uses of reinforced cement concrete are given below:

There are a lot of different types of structures and members of structures can be construct using reinforced concrete such as slabs, retaining walls, beams, columns, walls,foundations.
Reinforced concrete can be used as pre cast or cast in place concrete it means on site or of site..
In this age to construct the advance structure it is impossible to constrict it Without reinforcement or steel.

Behavior of RCC:

The steel that is high strength in tension, is placed in concrete, then the mixed material, reinforced concrete is not only resists compression but also resists bending and other tensile actions. A complex section where the concrete resists compression force and steel or rod resists tension force can be mold into any shape and size for the construction industry.

23. Plain Cement Concrete:

This types of concrete are used very commonly in construction. In plain cement concrete, the important components are cement, fine aggregate and coarse aggregate and mixed with a fix quantity of water or recommended water cement ratio.

The ratio of vital ingredients may be different within wide limits. A very commonly used mix design is called Nominal Mix Design that is 1 : 2 : 4.

Plain cement concrete (PCC) is mainly used in the construction of buildings and pavement, where high tensile strength is not needed. This concrete is also used in construction of Dams.

The density of Plain cement concrete (PCC) is 2200 to 2500 Kg/m³.
The compressive is 200 to 500 Kg/cm² and
Tensile strength is 50 to 100 Kg/cm².
Durability of plain cement concrete is very good.
There is no reinforcement in plain cement concrete. The major components are the cement, aggregates (fine and coarse) and water. Most used mix design is 1:2:4 that is the normal mix design.
Plain cement concrete is used in structures where it does not need high tensile strength.
In highly tensile or flexural area of the plain cement concrete is not used

24. Stamped Concrete:

Stamped concrete, is also known as textured or imprinted concrete, recreated stones that is slate, tile, brick and even wood. The wide diversity of pattern and color choices make it famous for beautifying patter, pool decks, driveways etc. Additionally, stamp concrete requires less maintenance than other materials. Reason is this concrete has superior durability and resistance against weather, colored and stamped concrete is the good way to bring the high end look of stone, brick, or wood to patios, pool decks, driveways and walkways.

Stamp concrete Is cheaper in price than natural stone, brick or pavers
It Offers limitless pattern and also choices of colors
It has good resistance against Slip when use with a non skid additive
Stamp concrete Is durable
It is very Easy to maintain when sealed

This concrete is mostly used for sidewalks, driveways, pool decks, and interior flooring. stamped concrete is a less expensive than other materials such as stone, slate or brick.

The three procedures are involved in stamped concrete used to differentiate it from other concrete procedures;

Base color is added
Accent color is added,
Stamping a pattern into the concrete.

These procedures be prepared stamped concrete with a color and shape similar to the natural material of building. Stamped concrete is durable than paved stone and give a good appearance.

History:

In the 1970s Stamping concrete is famous when it was first invented in the Concrete world. it as a new method to persuade the customer and make their budget work at the same time. This process of stamping concrete has been done since at 1950s. When stamping concrete is introduced, there were very few options of design and colors. After some time, industries of stamp concrete grew up now there is a lot of colors and different design. The benefit to using stamped concrete is that it can be applied to many various surfaces and textures, such as highways, patios, decks, and also floors in the house.

25. Fly Ash concrete:

It is also called pulverized fuel ash in the United Kingdom (UK), it is a product of coal combustion fly ash is composed of the fine particles of burned fuel that are force out of coal fired boilers together with the flue gases. in the boiler’s combustion chamber Ash is falls to the bottom it is known as firebox or called bottom ash. In advance coal fired power plants, fly ash is normally obtained by electrostatic precipitators or other filtration instrument before the flue gases reach the chimneys. From the bottom of the boiler bottom ash is removed, it is called coal ash. It is Depending upon the source and constitution of the burned coal, the ingredients of fly ash differ significantly, but all fly ash includes considerable amounts of silicon dioxide (SiO₂) (amorphous and crystalline), aluminium oxide (Al₂O₃) and calcium oxide (CaO), the main mineral compounds in coal bearing rock strata.

The small components of fly ash depend on the specific coal bed composition but it may involve one or more of the following elements or compounds found in discover concentrations (up to 100 ppm): arsenic, beryllium, chromium, hexavalent, boron.

cobalt, chromium, manganese, mercury, strontium and molybdenum along with minor concentrations of dioxins and PAH compounds. It also has unburnt carbon.

26. Silica Fume Concrete:

This type of concrete is also called micro silica, it is an amorphous or non crystalline polymorph of silicon dioxide (SiO₂), silica. It is a very fine powder that is obtained as a byproduct of the silicon and Ferro silicon alloy production and it consists of spherical particles the diameter of this particle is 150 nm. The use of this is that it is as Pozzolanic material for high performance concrete.

27. Ferro Cement Concrete:

It is a technique of construction using reinforced mortar that is applied over an “armature” of metal mesh, woven metal or metal fibers and thin or small dia of steel rods are closely spaced. The metal usually used is iron or other type of steel. The cement is typically a very rich mix of cement and sand in a 3:1 mix ratio; and when used for building boats no coarse aggregate is used, so that the material is not concrete.

Ferro cement is used to build thin, hard, strong surfaces and structures in other or complex shapes such as hulls for the boats, shell roof and water tanks. Ferro cement is invented in the 1840s in France and Netherlands. Ferro cement concrete is the creation of reinforced cement concrete. It has a wide range of other uses including shape, cast and well-constructed building elements. Ferro cement is a construction material composed of cement mortar and wire mesh. Ferro cement application in construction is extensive due to the low self weight, not required skilled labor, lack of framework etc.

Ferro cement concrete was developed by P.L Nervi he was an Italian architect in 1940. Quality of Ferro cement works are assured because the materials are prepared in machinery and implementation time at site is less. The Cost of maintenance is also low.

Properties of Ferro cement:

It is Highly resourceful form of reinforced cement concrete.
Ferro cement concrete is a type of thin reinforced concrete, in which large quantity of small diameter wire meshes is used
In Ferro cement Mesh may be metal or satisfactory substance.
alternatively, of concrete Portland cement mortar is used.
The Strength of Ferro cement depends on these factors quality of material (sand and cement) mortar mix and the second factor is quantity of reinforcing materials.

Materials for Ferro Cement:

The materials that is used in Ferro cement construction that is given below:

Cement
Fine Aggregate
Water
Admixture
Mortar Mix
Reinforcing mesh
Steel
Coating

Advantages of Ferro cement:

The advantages of Ferro cement concrete are follow:

The Basic materials used in Ferro cement are easily available in most countries.
It can be manufactured into any require shape.
The skill of worker is less required.
High durability
Low weight and it has long lifetime.
The cost of material is low in construction
Ferro cement concrete has good resistance against earthquake.

Disadvantages of Ferro Cement:

Structures constructed of it can be fail by collision with pointed objects.
Because of insufficient coverage of metal by mortar the corrosion is caused in reinforcing materials
It is tough to secure the Ferro cement with bolts, screws, welding and nail etc.
Large number of workers is needed.
The Cost of semi and unskilled workers is high.

Process of Ferro Cements:

manufacture the framing system.
install steel rods and meshes.
Curing

Applications of Ferro cements in Construction:

Housing
Marine
Agricultural
Rural Energy
Anticorrosive Membrane Treatment.

28. Pre Packed Concrete:

It is a unique method of placing concrete under water. When ‘tremie method’ or ‘bottom dump bucket method’ are not practicable then this method is acquire used where placing normal concrete is difficult, such as where reinforcement steel and immersed material are present, in underwater repairs, concrete and masonry repairs, or shrinkage of concrete should be minimum.

This method is done where the reinforcement is very complex or tricky or where definite positioning, arrangements like pipes, conduits, openings are needed to be mix in the concrete. This method is done in mass concreting, and piers, well staining etc.

This method or procedure is also called “grouted concrete” consists of placing the gravel only in the form and completely compacting it to form a prepacked mass. This mass is then grouted with the cement mortar of the required ratio. This process can be done for plain concrete or reinforced cement concrete.

29. Permeable Concrete:

It is also called pervious or porous concrete it is a type of pavement with a high level porosity that permits rain water to proceed through it into the ground below.

Also referred to as no fines or porous concrete, permeable concrete uses the matching materials as ordinary concrete excluded that the fine aggregate proportion of the mix is removed completely. In mix design the size of coarse aggregate should be 10, 14 or 20mm nominal size with careful control of the cement and water quantity the results in decrease particle packing potential with a stable void amount that is highly porous. this concrete can be used as a lightweight. The thermal conductivity values of permeable concrete are approximately half that of normal concrete, the insulation property of permeable concrete is good.

Application of Pervious Concrete:

pervious concrete imitates the natural process that happen on the ground’s surface, therefore decreasing runoff and returning water to underground aquifers. This concrete has few applications that is given below:

It has Low volume pavements
It is used in residential roads and driveways
sidewalks
parking lots
pervious concrete is used low water bridges
patios
well linings
walls (inclusive of load bearing walls)
swimming pool decks

History:

Pervious concrete was firstly intended in the 1800s in Europe and was used for different purposes of structure, including load bearing walls, in fill panels, and pavement surfacing. It became famous again after the World War II due to the shortage of cement

30. Smart Concrete:

It offers an substitute technique for keep an eye on the health of reinforced concrete structures. Smart concrete was introduced by Dr. Deborah D.L. Chung from State University of New York at Buffalo, United States of America The advantage of smart concrete is that it is secured by carbon fiber, which contain as much as 0.2% to 0.5% of the total volume. This can observe stress or strain in concrete structures before they fail. The technology of smart concrete has undertaken a lot of laboratory testing, but is still to strike the market.

In smart concrete it works by adding a small amount of carbon fiber to concrete with a normal concrete mixer to improve the electrical resistance of the concrete in reaction to strain or stress. under the circumstances, the contact between the fiber and cement matrix is affected when the concrete is damage or stressed, thereby affecting the volume electrical resistivity of the concrete. The strain is then decided by measuring the electrical resistance. This concrete is able of observe very small structural defects and consequently finds application in examine the internal situation of structures, especially after an earthquake

31. Volumetric Concrete:

This type of concrete is also called “volumetric mobile mixer” it is a concrete prepare on a truck or trailer that accommodate separate partition for sand, gravel, cement and water. Materials are mixed on a site to manufacture the exact quantity of concrete required. Volumetric mixers mostly use as delivery automobile for specialty high early strength concrete that harden too quickly for normal rotating drum “agitators,” and it is use in the construction of air field pavements. Some concrete distributor offer basic purpose concrete mass in a volumetric mixer as a workable different to ready mix if amount and scheduling are not fully known, in order to abolish wastage and prevent premature harden of the mix. Furthermore, typical batch plant opening fees for after some hours works do not apply.

History:

The history of volumetric mixing concrete is follow:

The mobile mixer was invented in 1964 AD by Harold Zimmerman, in Ephrata, United States of America. Because of the license, there was only one instrument build until the 1980s.
instrument manufacturers design a connection, (VMMB) in 1999, with six charter members together with Zimmerman Ind, Inc., Pro All Reimer, Bay Lynx, Custom Crete, Elkin and Cementech.

Advantages and Disadvantages of Volumetric Concrete:

There is few advantages and disadvantages of volumetric concrete that is given below:

Volumetric concrete decrease the wastage
This concrete reduces the costs by providing exact amount.
In volumetric concrete there is No risk of early harden of concrete if time is delay.
Allow delivery of less amounts of concrete.
in volumetric concrete the night time works do not need the re – opening of a concrete plant.

32. Decorative concrete:

This type of concrete is used for aesthetic of decorative purpose. The conversion of concrete into decorative concrete is perform through the use of a different of materials that may be have to do with during the concrete placing procedure or after the cured of concrete, these materials and or systems include but are not insufficient to stamped concrete, acid staining, decorative overlays, polished concrete, concrete countertops, vertical overlays etc.

33. Rubberized Concrete:

The waste of rubber additives in Reinforced Concrete act as an absorber and stabilize entire internal stresses in concrete. Rubberized concrete may be used in highway construction as a shock absorber in sound barriers, as a sound blower and also in buildings as an earthquake shock wave absorber. Although more important research is required before strong suggestion can be made Topcu and ozcelikors in 1991 AD Topcu and Avcular in 1997 AD.

The addition of scrap rubber to improve bitumen is extensively used to reduce the pollution of environment of crumb tires and to improve high quality of hot bituminous mixes.

There are two methods used to include waste tire rubber into asphalt as wet processes and the dry process.

Wet Process:

The rubber of tire is first integrating with the asphalt mixer and break down before the binder is used to manufacture the hot mix asphalt (HMA). The wet process having two types

(1) terminal blend or field blend.

(2) wet process high viscosity.

Terminal blends are prepared by combine scrap rubber and other additives with bitumen at the supply terminal. The rubber has to be finely ground less than or equal to 300 μm, so that it can be simply absorbed by the mixer and can be put in elimination by the little mixing available from circulation of tank. Normally these mixes include less than 10% percent mass of rubber, as higher mass are more move to rubber particles isolate from the bitumen. Wet process high viscosity binders are creating beside to a hot mix asphalt production facility by using professional instruments.

34. Geo polymer Concrete:

It is produced by reacting aluminate and silicate with a caustic activator. usually, waste materials for instance fly ash and slag from iron and metal manufacturing are used, that helps to clean environment. This is because the waste material is in fact containing within the concrete and it does not to be disposed of as it is being used. Geo polymer concrete is the type of concrete in which it does not need heat to prepare it and it does not make carbon dioxide (CO₂). while Portland cement concrete need both heat and carbon dioxide.

Advantages of Geo Polymer Concrete:

It has outstanding advantages over conventional concretes. It is much more long life than normal concrete and need limited repair, therefore saving large amount of money that would otherwise have to be consumed on repairing and maintaining concrete construct infrastructure. Geo polymer concrete is the advance similar of the earliest concretes for instance these concrete is used by the Romans that have survived for thousands of years. Geo polymer concretes will safely bear hundreds of years while conventional concretes will last for tens of years.

Geo polymer concrete has good resistance against corrosion and fire,
It has high compressive strength.
Geo polymer concrete has good tensile strengths, and
it gains its full strength quickly (cures fully faster).
Geo polymer concrete is also shrinks less than conventional concrete.
Geo polymer cementis hardening at room temperature.

Geo polymer cement is environmentally friendly option then conventional portland cement. It relies on very little processed natural materials or industrial byproducts to seriously decrease the carbon foot print of cement manufacturing, while also it have high durability then other standard concretes.

Geo polymer cements will be cure more quickly than Portland cements.

Most of peoples are confusion between the meanings of these two terminology “geo polymer cement” and “geo polymer concrete”. The cement is a binding material, while concrete is a composite material resulting from the mixing of cement with water and coarse aggregates. Materials of both types (geo polymer cements and geo polymer concretes) are available internationally in every markets.

35. Plum Concrete:

The plum concrete is the type of concrete in which coarse aggregate, fine aggregate and cement are mixed together. Plum concrete is placed below the foundation or footing of a structure for the purpose of to perform a level surface for distribution of load equally. plum is a word that means large stones. Technically it is called boulders or coarse aggregates..
The plum concrete is an economical variation of high volume concrete. If the thickness of PCC is more or large then plum concrete is good for use.

plum concrete is mostly used below the foundations or footing where due to steep slope of the strata, the amount of leveling course could be more.

Application of Plum Concrete:

This concrete is used below footings of buildings such as residential buildings having small portion where the slope of below the ground single footing is 1:10 to 1:50. Plum concrete is used to save the cost. This will result to reduce the cost of whole building.
Plum Concrete is also used in construction areas that need excessive concrete placements such as dams or bridge piers. In this type of construction, the size of coarse aggregate is used about 150 mm to mix a plum concrete.

36. Gypsum Concrete:

Gypsum concrete is a mixture of gypsum plaster, cement and sand. It is used as a floor underlayment, wood frame and concrete construction for resisting the fire, decreasing the intensity of sound, reduce heating and floor leveling. The brand name Gyp Crete, a Maxxon Corporation trademark, promote the use of gypsum concrete by construction professionals and architects.

The Gyp-Crete consist of calcined gypsum, sand, water, and small quantity of different additives. Additives are polyvinyl alcohol, sodium citrate or fly ash, Colloid deformer, sodium or potassium derivatives of nephthalene sulfonate formadehde contraction.

S. No	Components	Amount	Approx.(%)
1	Atmospheric calcined gypsum	36.2 Kgs	24%
2	Polyvinyl Alcohol	0.204 Kgs	0.14%
3	Extender	22.27 gr	0.00098%
4	Fluidizer	108.8 gr	0.0047%
5	Sand	68 to 90 Kgs	57%
6	Water	6 to 8 gal	19%

Polyvinyl alcohol is used to stop or safe the surface of the concrete from becoming dusty. While the exact use of polyvinyl is not known, when the concrete is hard, water goes to the surface, conduct with it fine, dusty particles. the water vaporizes, the dusty particles are rest on the surface. the polyvinyl alcohol stops the dusty particles from move upwards with the water.

The concrete is produce on site using a truck. The truck contains water tank, a mixing tank, a holding tank, a pump, and a transporter for the sand and calcined gypsum. A hopper for the sand and gypsum is arrange outside on the automobile.

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