Self Compacting Concrete

The self compacting concretes were invented by Okamura and Ozawa [30] and after two years of studies the first constructions with SCC apphcations Akashi Kai-kyo Bridge and Trans Tokyo Bay Bridge were erected in 1988. 

Cement is the main powder component of SCC and, as in the other types of concretes, is governing the strength and strength development. Cement has also the decisive influence on the rheology of self compacting concrete mixture. 

The other fine powder components, added to control the workability of concrete mixture are fly ash, limestone flour and ground granulated blastfurnace slag. The content of these mineral additions can be substantially high when cement type CEM 1 is used they substitute up to 50% cement, particularly that of class 42.5. One can conclude that the Portland cements with mineral additions can be also applied. The effect of limestone flour on the properties of concrete mixture was studied, among the others, by Gizeszczyk [32], 

The self compacting concrete mixture should have high plastic viscosity and low yield stress value. It is ensured by the high content of fine powder fraction (Fig. 10.4) and low w/c ratio [33], but the use of superplasticizers is essential too. It must be the polycarboxylates or poly carboxylic ethers admixtures. SCC technology 

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Modem high-performance concretes (such as non-dispersible underwater concrete, self-compacting concrete, and concretes used at below freezing temperatures) have necessitated the use of special admixtures, often requiring on-site addition. Figure 7.57 shows a special dispensing unit with storage tank used for this purpose. 

Mix no. Description 1 Control 2 Addition of admixture normal workability 3 Addition of admixture self-compacting concrete... 

Some types of concrete have special properties that are useful with regard to the durability of reinforced-concrete structures. For example, conventional concrete with mineral additions, high-performance concrete (HPC) and self-compacting concrete (SCC) are briefly discussed here. 

H. Okamura, M. Ouchi, Self-Compacting Concrete. Development, present use and future , Int. Conf Self-Compacting Concrete, Stockholm,... 

Keywords biopolymers, cementitious materials, polycarboxylate ether, stabilising agent, starch ether, self-compacting concrete, superplasticizer... 

The end of eightieth—Okamura applied the self compacting concrete. 

There is no doubt that the self compacting concrete (SCC) and the reactive powder one (RPC) will be categorized as the new concretes, because they are the produets of quite unique, new technologies. The latter one is classified as a low temperature eeramies. Such an approach to the RPC was presented for the first time in the Roy s paper [2]. 

Okamura, H., Ozawa, K. Mix Design for Self-Compacting Concrete. Concrete Library of JSCE, No. 25. (1995)... 

M. A. S. Mohamed, E. Ghorbel, and G. Wardeh, Valorization of micro-cellulose fibers in self-compacting concrete, Constr. Build. Mater.2A 2), 2473-2480,2010. 

Despite the reduced workability of FRC, recent studies have shown that it is possible to produce fibre-reinforced self-compacted concrete (FR-SCC), with good flow properties and suitable properties. Akcay and Tasdemir (2012) have studied steel fibre in FR-SCC and found that the main parameter affecting the flowability of FR-SCC is the geometry of fibres, rather that the fibre strength. El-Dieb and Taha (2012) show that suitable workability of FR-SCC depends on the fibre content. For polypropylene fibres, the maximum fibre content should be 1000, 1200 and 1300 g/m for SCC mixtures with cement content 350, 400 and 500 kg/m respectively. For steel fibres, one should limit the fibre aspect to 50, 90 and 100 kg/m for SCC mixtures with cement content of 350, 400 and 500 kg/m respectively. 

El-Dieb, A.S., Taha, R.M.M., 2012. How characteristics and acceptance criteria of fibre-reinforced self-compacted concrete (FR-SCC). Construction and Building Materials, 27(1), pp. 585-596. 

Sholihin, A.A., Purnawan, G., Alaydrus M.S., 2011. Fresh state behavior of self compacting concrete containing waste material fibres. Procedia Engineering, 14, pp. 797-804. 

Self-compacting concretes (SCC) and self-levelling concretes (SLC)... 

A series of experimental verifications carried on in situ by Zhu et al. (2001) proved that homogeneity of self-compacted concrete placed in tall columns and walls was entirely comparable with that of ordinary vibrated concretes. Test were carried out using drilled cores at different levels, as well as using various non-destructive methods, and have shown that the results for see were even slightly more uniform along the height of tested elements of natural scale. 

Brouwers, H. J. H., Radix, H. J. (2005) Self-compacting concrete theoretical and experimental study . Cement and Concrete Research, 35(11) 2116-36. 

Ouchi, M., Nakamura, S., Osterson, T., Hallberg, S. E., Lwin, M. (2003) Applications of self-compacting concrete in Japan, Europe and the United States . ISHPC. Available at http//.www.fhwa.dot.gov/bridge/scc.pdf... 

Zhu, W., Gibbs, J. C., Bartos, P. J. M. (2001) Uniformity of in situ properties of self-compacting concrete in full-scale structural elements . Cement and Concrete Composites, 23 57-64. 

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