Self-compacting concrete

Self-compacting concrete is a type of concrete that is more fluid than normal concrete and that compacts itself. Unlike normal concrete, no vibration is required for compaction. Flows through connection areas with reinforcement.

Most of us know what self-compacting concrete means. It is also called SCC or SCC concrete. Let's discuss other technical and important factors related to self-compacting concrete.

Main advantage of self-compacting concrete

• Better finish
• Reduction in the number of employees
• Past construction
• Easy for Concrete
• Friction resistant concrete
• Friction connection with reinforcements
• Increase durability
• Can be used to concrete thinner sections
• Economical production
• Lower permeability
• Reduced probability of void formation in areas of rebar overload
• Can be used for concreting irregular structures due to the fluidity of the concrete
• Pumping concrete is comparatively easier.

Disadvantages of self-compacting concrete

• Formwork costs increase because the pressure on the formwork increases as the fluidity of the concrete increases.
• Special attention is required when selecting concrete material.
• The consistency of the selected materials must be maintained. Material misappropriation can have harmful effects.
• It is preferable to carry out several test strokes to ensure the uniformity of the concrete and identify any deviations.
• Work is strictly monitored

Due to these advantages and disadvantages, left-hand compacted concrete is used frequently and continuously.

Self-compacting concrete is often used in the following work areas.

• Pile construction
• Construction of slab foundations
• Build structures with reinforcing jams
• Drilled shafts
• Concreting columns
• Thick layer concreting, such as B. Panels in tall buildings.
• Construction of pile slabs

The production of compacted lightweight concrete is nothing new in the construction industry. It was developed a long time ago and different types of concrete have been produced throughout history.

Furthermore, this production represents a valuable foundation for the industry, as it brings many advantages and has solved design problems related to specialized work.

Let's discuss the main aspects that affect the production and construction of this type of concrete.

Factors affecting self-compacting concrete

• Hot weather can affect concrete drilling
• The material section must be safe
• When transported over long distances, the fluidity of concrete can be impaired.
• Furthermore, loss of concrete workability can lead to a reduction in expected performance.
• Particular attention is paid to Additives as Flowing Agents are used because they are more sensitive to changes in the condition/source of materials such as fine and coarse aggregates.

The production of self-compacting concrete is not the same as that of normal concrete. There are some restrictions and limitations.

Properties and purpose of concrete additives

1. cement
2. Fine aggregates
3. Coarse aggregates
4. Use of mineral additives
5. Chemical additives

cement

Ordinary Portland cement can be used to make self-compacting concrete.

If necessary, the cement specified in BS EN 197 may be used.

An appropriate elongation class The choice of cement can also be based on the expected elongation of the concrete.

Additionally, the article Cement and cement additives You can find more information about cement here.

Fine aggregates

As we all know, concrete mix uses fine aggregate.

In the production of self-compacting concrete, the content of fine aggregates increases slightly, while the content of coarse aggregates decreases.

• Reverse sand or manufactured sand can be used
• The gradation of the material is uninformed
• The moisture content of the unit must be monitored and on alert
• A particle size of less than 0.125 mm could be used.

Furthermore, the consistency of supply of materials selected for experimental mixtures from the same source must be maintained.

Coarse aggregates

Special attention should be paid to the selection of coarse aggregates for self-compacting concrete as they have a significant impact on the workability of the concrete.

• Maximum aggregate size is generally limited to 20 mm
• If the area to be concreted is blocked, the aggregate size can be limited to 10-12mm
• High quality material must be used
• Rounded aggregate with effect on the workability of concrete could be used

Mineral additives

The following mineral additives can be added to concrete:

1. fly ash : Improving the quality and durability of concrete
2. Silica powder : Improves mechanical properties
3. Ground granulated blast furnace slag (GGBS): improving rheological properties
4. Rock dust: increase in fines content

Chemical additives

New generation Flowing agent are added to concrete to improve concrete properties.

There are Additives that can fulfill many functions. For example, a highly effective water-reducing superplasticizer additive can also be used as a retarder.

Chemical admixtures are used to reduce the water content of concrete and make it more workable.

Self-Compacting Concrete Test

To guarantee the quality of the concrete and the workability of SCC concrete, several tests are carried out in addition to the strength tests.

• Fill test
• Passing the skills test
• Segregation resistance test

Different test methods are available for each test method, as shown in the following figure. Furthermore, it is mandatory to test concrete of this type to ensure the quality of the concrete.