Everything about Self Compacting Concrete
Concrete that is self-compacting has a flowing mixture of concrete that is capable of compacting or consolidating by gravity as soon as it has been formed. A hunk of self-compacting concrete has the benefit of being able to flow and flow freely, which makes it a good choice for concrete placement in difficult conditions and in sections made up of congested or narrow reinforcements.
A construction site's hearing-related damages caused by concrete vibration can be reduced with the use of self-compacting concrete. Self-compacting concrete also significantly reduces the amount of time needed to set big concrete sections.
During the late nineteenth century, when skilled labor supplies in the construction industry were declining, a need for concrete that was self-compacting was felt in order to overcome issues of defective workmanship that were seen due to a decline in the availability of skilled labor in the industry.
To study the properties of concrete that is self-compacting, a team was formed at the Japanese University that was in charge of the study. During the late 1980s, there were first attempts at producing self-compacting concrete. It was called high-performance concrete at first, and later on, it was named self-compacting concrete.
Components used in forming this Self-Compacting Cement
In order to improve the workability of self-compacting concrete, aggregates are required. The materials required for proper self-compacting concrete are identical to those needed for regular cement.
A cement type that conforms to EN 197 can be used in order to produce a concrete product of the desired strength, durability, and appearance, and the choice of the type of cement will be determined by the parameters of concrete that need to be met.
The presence of high content of ten percent or more may lead to problems related to poor workability.
Self-Compacting Concrete can be made using any typical concreting sand. Sands can be either spherical or crushed. For a suitable chemical combination of concrete, the number of fines that are deemed to be powder must be smaller.
All aggregate kinds with the typical maximum size are employed. However, self-compacting concrete has also been employed with particle sizes up to 40 mm. Crushed aggregate among the many forms of aggregate improves strength well, whereas rounder aggregates increase flow capacity due to decreased frictional resistance.
During the construction process, the use of water quality is identical to that used for the construction of reinforced concrete and prestressed concrete.
Other Mineral Components
Depending on the mix design and the properties that are required, mineral admixtures may be used in a variety of ways. A list of the different mineral admixtures and their properties is provided below:-
1. GGBS: Ground Granulated Blast Furnace Slag improves the rheological properties of self-compacting concrete by enhancing the rheological properties.
2. Fly Ash materials: The smaller pores in the interior concrete matrix are improved by the tiny fly ash particles. The SCC constructions' strength and durability are increased as a result.
3. Silica Fumes: The self-compacting concrete structure's mechanical qualities are improved by the application of silica fumes.
4. Stone Powder: Stone powder is used in SCC to enhance the mix's powder content.
In SCC mix design, new-generation superplasticizers are frequently employed. Air entraining chemicals are utilized to increase the concrete structure's resilience to freeze and thaw. Retarders are used to limit the setting time.
Benefits of Self-Compacting Concrete
Concrete that is self-compacting has the following main advantages:-
1. The concrete structure's permeability is reduced.
2. SCC allows for creative freedom in concrete building design.
3. SCC construction moves more quickly.
4. The issues brought on by vibration are resolved.
5. Easy concrete placement leads to significant cost savings.
6. The construction's quality is improving.
7. Compared to conventional concrete constructions, the concrete structure has a high level of dependability and durability.
8. There is less vibration-related noise. This also lessens the problems with hand-arm vibration syndrome.
Drawbacks of Self-Compacting Concrete
Concrete construction based on self-compacting technology faces the following limitations:-
1. There is no internationally recognized test standard for SCC mix design.
2. Construction costs are higher than those of traditional concrete construction.
3. More trial batches and lab testing will be necessary when using tailored mixes.
4. More accuracy is required in the monitoring and measuring.
5. SCC material selection is more rigorous.
Tests of Self Compacting Concrete
Slump test: The same tools that are typically used for standard slump testing must be employed. The test procedure differs from the norm in that the concrete sample is put into the mold without a reinforcing rod, and the sample collapses when the slump cone is taken off.
To learn more, watch the following video tutorial.
Video Source: civilogy
V-Funnel test: Among the new tests available for concrete is the V-funnel test, which is equipment that is made up of a V-shaped funnel and was developed in Japan. It is being measured how long it takes for the self-compacting concrete created in the funnel to flow through the equipment as it passes through it.
L-Box test: The L-box test technique uses a test device with a vertical part and a horizontal aperture into which concrete can flow. Upon release, a trap opening from the vertical section passes through reinforcing bars set up at the junction of the two regions of the device.
Wrapping it up
It may be said that self-compacting concrete reduces labor costs when concrete is being cast, lowers noise levels in factories and building sites, and generally helps to enhance the atmosphere of construction sites.