Admixture (English)

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Group 3 :1) AHMAD DWI SANTOSA/31121100502) APRIANI HOTMAIDA/3112110001

3) DANIEK LISTIYA CANDRA/3112110014

4) FRANS DANIEL HUTABARAT/3112110023

5) ULFI MULYANINGRUM/3112110043BUILDING CONSTRUCTION

CIVIL ENGINEERING

STATE POLYTECNIC OF JAKARTA

2013

ENGLISH PRESENTATIONADMIXTURE AND ADDITIVE


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Admixtures are those ingredients in concrete

other than Portland cement, water, and aggregates

that are added to the mixture before or during

mixing.


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1. To reduce the cost of concrete construction.

2. To maintain the quality of concrete

3. To reduce water content without changing workability.4. To adjust setting time.

5. To increase strength.

6. To reduce segregation and/or bleeding.7. To improve pumpability.

8. To improve potential durability and reduce

permeability.


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The type of admixture that used to reduce the

quantity of mixing water required in the fresh concrete

but concrete has a good workability

Materials :

> Lignosulfonates.

> Carbohydrates.

> Hydroxylated carboxylic acids


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By Using Water Reducing Admixture will beachieved three things, there are :

1. Just increase workability

2. Increase the compressive strength of concrete3. Reduce the cost

Dosage

The typical dosage of a WRA varies from 200 ml to 450 ml per 100kg of cementitious material.


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+ WRA

- Water

Compressivestrenght >A

Workability = B

+WRA

-Water

-Cement

Compressivestrenght =A

Workability = B

+WRA

Compressivestrength > A

Workability = B

Compressivestrength = A

Workability= B


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These admixtures slow the chemical reaction ofthe cement and water leading to longer setting timesand slower initial strength gain.

Materials used as retarders are:

- Lignin, - Borax,

- Sugars, - Tartaric acid and salts.

Dosage

Dosages for retarders are between 150 ml and 500 ml/100 kg cementitious material.


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It used to accelerate the process of binding and strengthdevelopment of concrete at an early age. It is used to shortenthe time of the binding cement to accelerate the achievement of

concrete strength.Typical Materials are:

- Calcium chloride: most commonly used for plain concrete.

- Triethanolamine. - Calcium nitrate.

- Calcium formate. - Calcium nitrite.Dosage

The maximum dosage that can be added to concrete is 2%of cement weight.


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This type have dual function. There are to reduce thequantity of mixing water required and to retard the processof binding.

With adding this admixture to concrete, It can reducethe quantity of cement that comparable with the quantityof water that reduced

The shape of this admixture is liquid. So in mix designconcrete planning, the weight of admixture should beadded as the total weight of water in concrete


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This type have dual function. There are to reduce the

quantity of mixing water required and accelerate the

process of binding and hardening concrete.

By adding this admixture, it will get the concrete with

quick binding time and low water levels but it still workable.


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This type have function to reduce the quantity of

mixing water that required to produce concrete with

consistency as much as 12% or more than 12%.

By adding this admixture, it will get high-strength

concrete with a little quantity of mixing water but the rate

of workability is higher.

The effectiveness of the plasticizer is increased withan increasing amount of cement and fines in the

concrete.


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Superplasticizer uses to get addition of 50% strength at the

age of 1 day

Superplasticizers material :

-chemical compounds such as sulphonated melamine

formaldehyde,

-Sulphonatednaphthalene,

-formaldehyde,

-modified lignosulphonates and-Polycarboxylate based materials.

Dosage

Recommended dosage 1%-2% of cementitious material.


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This admixture have function to reduce the quantity

of mixing water that required to produce concrete with

consistency as much as 12% or more than 12% and toretard binding and hardening concrete.

This material is combined by superplasticizer with

retard the setting time of concrete.


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It used to stabilize or forming microscopic air

bubbles in concrete.

Air entraining agent will dramatically improve thedurability of concrete exposed to cycles of freezing and

thawing.

Dosage

Typical dosage for air-entraining agents is between 50 mland 150 ml per 100 kg of cementitious material.


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There are two types of AEA :

1. Type detergent

In general AEA represent detergent type, the active agentto the surface. This substance is usually in the form of organic

matter as the raw material of soap, so that when mixed with

water will be foam and the foam will be scattered in the concrete

mix.The addition of AEA in concrete has little shrinkage

properties and makes concrete more watertight.

The primary ingredients used in air-entraining admixtures

are salts of wood resin (Vinsol resin), synthetic detergents, saltsof petroleum acids, etc.


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2. Type of non detergent

This type usually a fine aluminum powder. When

this powder mixed with water in the concrete will react

to form hydrogen air bubbles. Usually the material usedalso stabilizers (sodium stearate) so the bubble can be

spread evenly and stable.


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1. Pigments can be used to change the color of concrete, for

aesthetics.

2. Corrosion Inhibitors. These admixture are used to minimize the

corrosion of steel and steel bars in concrete.

3. Bonding agents are used to create a bond between old and new

concrete (typically a type of polymer).


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A substance added to a material in concrete

mix to improve the properties of concrete(mineral admixtures), or as a replacement for

Portland cement (blended cements).

Additive is a solid material which is refined


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Addition of additive usually added at thin concrete,

where its concrete lacking of smooth aggregate and

concrete with ordinary cement rate but require to be

pumped at distance which far.


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1. Repairing Concrete Workability

2. Reduce heat of hydration

3. Improve the durability of concrete

4. Increase the compressive strength

5. Enhance resistance against alkali-silica reaction

6. To adjust setting time.

7. To make concrete more watertight


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Type of Additive are:

Fly ash

Fly ash is the result of a subtle separation ofcombustion from the combustion of coal suppliedfrom coal combustion chamber. The low calcium flyashes retard the setting of cement

In practice, fly ash can be introduced intoconcrete in one of two ways :

1. Fly ash may be used in place of portland cement

2. Fly ash may be introduced at the concrete mixingstage.


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Ground granulated blast furnace slag

Ground granulated blast furnace slag is a product of steel

production is used to partially replace Portland cement (by up

to 80% by mass). It has latent hydraulic properties.


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Silica Fume

Silica Fume is a product of the production of silicon. Silica

fume is similar to fly ash, but has a particle size 100 times

smaller. Silica fume is used to increase strength and durability

of concrete, but generally requires the use of superplasticizers

for workability


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High Reactivity Metakaolin

Metakaolin produces concrete with strength and durability

similar to concrete made with silica fume. metakaolin is usually

bright white in color, making it the preferred choice for

architectural concrete where appearance is important.


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1. Don't use admixture if not know the target.

2. Admixture will not make poor concrete become good concrete

3. An admixture can change more than one characteristic of

informing against concrete

4. Observation to this materials very important, including

observation of its influence to concrete.


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These two factors define the general rules for storage.

Admixtures should be protected from frost, as most have

freezing points at or below 0C. andAdmixtures generally

contain preservatives to reduce biodegradation and extend shelf

life.

Admixtures are normally stored on site in 200 drums or in

bulk storage tanks. Bulk liquid storage tanks are often supplied,

serviced and maintained by the admixture supplier. Drums

should be handled with care.


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The correct dosage of admixture is crucial for satisfactory

mix performance and the proper use of well maintained and

calibrated dispensing equipment is essential.

For the majority of admixtures it is not necessary to

change the concrete mixing procedure. Any special requirements

will be given in the admixture manufacturers product literature.


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Admixture (English)