Self Compacting Concrete (SCC) is an advanced type of flowable revolutionary concrete that has more durability and abilities to flow and move without the use of any mechanical vibrations.
SCC is a flowable and non-segregating concrete that flows by its own weight hence it is poured in a construction where the reinforcement is dense as we are unable to use mechanical vibrations. SCC is a costlier concrete than conventional concrete, though it reduces construction time as well as increases workability.
If concrete is a country it is the third-largest country after air and water as it is the most consumable substance on earth after air and water. Concrete also leads to 2.5% of global carbon emissions.
SCC contains the same water-cement ratio as conventional concrete but has slightly higher strength. It must have a relatively higher velocity than normal concrete at the time of placing.
43 or 53-grade cement and Ordinary Portland Cement could be used.
In some countries of the world, water is scarce, so we could use reclaimed water, Groundwater, waste, and treated water from ready mix concrete plants.
The aggregates should not be more than 20 mm in SCC, If the structure size is congested we could 10-12 mm aggregates.
Mineral Admixtures like fly ash ground-granulated blast-furnace slag, silica fume, limestone powder.
Chemical Admixtures like melamine-formaldehyde, sulfonated naphthalene formaldehyde condensates, sulfonated melamine formaldehyde condensate, and polycarboxylate ether-based superplasticizer.
Advantages of Self Compacting Concrete
- It reduces the construction time of the structure.
- It does not require skilled labor.
- Furthermore, it gives immense freedom to design a structure without any agitation.
- It reduces noise pollution caused by mechanical vibrations.
- It increases construction quality.
- It makes pumping easier.
- Results in faster construction.
- It leads to the improvement of structural integrity.
- It recommended for longer spans and deeper sections.
- Likewise, it reduces the wear and tear of equipment.
- Not only that, but it enhances the finishing of structures
Disadvantages of Self Compacting Concrete
- The design mix requires more lab tests and trial batches. To make sure everything is fine with the structure
- Absolute monitoring and measurements must be required.
- Construction cost is more than normal concrete.
- Rigorous material selection in SCC.
- An increase in temperature affects SCC. Results in a reduction of compressive strength.
- Delay in construction site could affect the performance of concrete mix design.
Properties of Self Compacting Concrete
Self Compacting Concrete has properties which make it significantly more durable and reliable than conventional concrete.
These properties are as follows:-
- Filling Ability – It is the ability that defines the ability of concrete to flow and fill formwork with its space properly under its own weight and give accurate finishing
- Segregation ability -It is the ability of concrete by which it maintains its flowability and passing ability throughout its transportation.
- Passing Ability – It is the ability of concrete to pass through dense reinforcement and must have an aggregate size of less than 20 mm.
Tests of Self Compacting Concrete
Tests are conducted on SCC in its fresh state as it achieved the required properties.
- Filling Ability Tests.
- Segregation Resistance Test.
- Passing Ability Tests.
Filling Ability Tests:- Fill Box Test and U Box Test are used to check the filling abilities of SCC.
Segregation Resistance Test:- V funnel Test is used to check flowability
Passing Ability Test:- L Box Test and Slump Test are used to determine the passing ability of SCC.
Applications of Self Compacting Concrete
- Self Compacting Concrete is used in the construction of retaining walls as it has highly stable and durable characteristics.
- It is used in pile and raft foundations.
- It is also used for the maintenance, repair, and rehabilitation of structures.
- SCC is also used in heavy and dense reinforced structures.
Case Studies of SCC
COMCAST CENTER – Philadelphia
Comcast Center is the second-tallest building in Philadelphia. It has 58 Story and height is 978 Foot. It is a LEED-GOLD certified skyscraper its construction was started in 2005. The skyscraper used mainly three types of concrete mixes – 6,000, 8,000, 10,000 psi.
NATIONAL MUSEUM FOR THE AMERICAN INDIAN
The National Museum For The American Indian is constructed in 2004. As the structure has custom formwork, therefore, use of a vibrator is prohibited.
Self Compacting Concrete has done revolutionary changes in civil engineering as it is cost-effective, reliable concrete. It saves time and does not need skilled labor in construction. This advancement in civil engineering has a significant amount of success globally. The main focus point of concrete is its manufacturing as it requires a proper amount of raw material as per its design mix these raw materials as well as admixtures mix in a proper proportion and transit properly to the site, and we must have a proper formwork to withstand the concrete.