Self-Compacting Concrete
Self-compacting concrete (SCC) or self-reinforcing concrete is high fluidity concrete (HFC). Self-summarization means that the formwork can be easily positioned and cropped at its own center of gravity, with high traffic strength, without external reinforcement from vibration.
It is characterized by high visco-plastic deformation, resistance to segregation, and high filling capacity resulting from the ability to maintain a consistent composition throughout transport and placing. SCC has advantages of fast construction, noise reduction, good structure, and energy efficiency.
SCC enables concrete to be placed in structures that would otherwise have been impossible to construct with concrete and have undergone dramatic improvements in construction efficiency of extra large-scale structures, such as bridge tower pile caps (Figure 6-42). Self-compacting concrete was first systematized by Okamura in 1988 in Japan. In the beginning, he named it “high-performance concrete” (HPC).
SCC / HPC was initially developed in Japan to meet construction needs. The postwar reconstruction of Japan resulted in the 1960s
The boom in building and infrastructure construction. Since Japan is a major seismic area, most structures need to be reinforced to be earthquake-resistant, especially in beam-column joints. Due to these scenarios and the need for rapid project delivery, many structures were not able to be built with sufficient compact concrete.
In a decade or two, many reinforced concrete structures have deteriorated. To address the durability problem of new concrete construction, of the University of Tokyo. Okamura started the project. His investigation found that adequate compression was the most common cause of deterioration of concrete structures and suggested an increase in the flow of fresh mixture to eliminate compaction, i.e. “Self-compacting” concrete mixtures (Kuroiwa et al., 1993).
In Europe, a large, industry-led (NCC Sweden, GTM-Vinci France, and six other partners) research project was funded by the European Commission in 1997 (Greiners, 1997). European Figure 6-42 Application of Self-Compacting Concrete for In situ Piles
The SCC Project proved that SCC is practical to apply using a variety of local materials and has the expected benefits in real construction practice. The working group at (SCC), established under the RILEM TCI45-WSM, was converted to a new RILEM Workgroup TCI74- SCC, and its Guidelines on the SCC were published in 2000 (Peterson and Skarendal, 2000).
The fluidity of self-compacting concrete was realized with the invention of a high range of water-reducing admixtures or superplasticizers. The different approach to raising consistency was to increase the cement paste content. 6.5.1
Advantages of self-compacting concrete:
SCC is considered an environmentally friendly material. First, the application of SCC in the construction site eliminates the need for vibration to compact the concrete.
Compression of fresh concrete by vibration is often referred to as heavy physical activity and unpleasant activity in the concrete construction process. Vibration can cause high noise levels, up to 90 dB, which is not good for public health, especially for operators. Second, the acceleration produced by the vibrators can reach 0.70 to 4 m / s2 and has the potential to injure the vibrator operator.
Therefore, removing vibration can significantly improve health and the environment in the concrete construction space (Bartos and Setura, 2001). Third, vibrator operators need some skill and experience in compressing fresh concrete into satisfactory concrete. Lack of experienced workers in many areas can lead to low-quality concrete.
The application of (SCC) can solve this problem and ensure consistent high quality for concrete structures. The application of SCC makes construction automation possible, leading to higher productivity. It is not only in prefabricated concrete production But for in situ concreting operations.
The introduction of SCC benefits architects and structural engineers and ultimately the users of buildings. New types of structural elements, which cannot be made of conventional concrete, can be produced using SCC. Such elements consist of a variety of steel-concrete structural elements with more complex shapes that are thinner with a heavier reinforced cross-section.
Property evaluation of fresh self-compacting concrete:
The main difference between conventional concrete and SCC is the flow in the fresh phase. Because of its water-like liquidity, the methods used to evaluate the viability of conventional concrete at the fresh stage are not suitable for SCC.
Thus, starting with the invention of the SCC, much of the research is focused on the asset valuation of the SCC at a new stage. To date, there are still many standardized testing methods, not widely recognized worldwide, and presented in this section.
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