SELF-COMPACTING CONCRETE
SELF-COMPACTING CONCRETE
Masahiro OUCHI 1
SUMMARY
Self-compacting concrete was first developed 1988 in order to achieve durable concrete structures. Since then, various investigations have been carried out and the concrete has been used in practical structures in Japan, mainly by large construction companies. Investigations for establishing a rational mix-design method and self-compactability testing methods have been carried out to make the concrete the standard one.
Keywords: self-compacting concrete, development, self-compactability of fresh concrete, mix-design, testing methods for self-compactability, superplasticizer.
DEVELOPMENT OF SELF-COMPACTING CONCRETE
For several years beginning in 1983, the problem of the durability of concrete structures was a major topic of interest in Japan. To make durable concrete structures, sufficient compaction by skilled workers is required. However, the gradual reduction in the number of skilled workers in Japan 's construction industry has led to a similar reduction in the quality of construction work. One solution for the achievement of durable concrete structures independent of the quality of construction work is the employment of self-compacting concrete, which can be compacted into every corner of a formwork, purely by means of its own weight and without the need for vibrating compaction (Fig. 1). The necessity of this type of concrete was proposed by Okamura in 1986. Studies to develop self-compacting concrete, including a fundamental study on the workability of concrete, have been carried out by Ozawa and Maekawa at the University of Tokyo [1].
The prototype of self-compacting concrete was first completed in 1988 using materials already on the market (Fig. 2). The prototype performed satisfactorily with regard to drying and hardening shrinkage, heat of hydration, denseness after hardening, and other properties
[1] [2]. This concrete was named “High Performance Concrete.” and was defined as
Masahiro OUCHI 1
SUMMARY
Self-compacting concrete was first developed 1988 in order to achieve durable concrete structures. Since then, various investigations have been carried out and the concrete has been used in practical structures in Japan, mainly by large construction companies. Investigations for establishing a rational mix-design method and self-compactability testing methods have been carried out to make the concrete the standard one.
Keywords: self-compacting concrete, development, self-compactability of fresh concrete, mix-design, testing methods for self-compactability, superplasticizer.
DEVELOPMENT OF SELF-COMPACTING CONCRETE
For several years beginning in 1983, the problem of the durability of concrete structures was a major topic of interest in Japan. To make durable concrete structures, sufficient compaction by skilled workers is required. However, the gradual reduction in the number of skilled workers in Japan 's construction industry has led to a similar reduction in the quality of construction work. One solution for the achievement of durable concrete structures independent of the quality of construction work is the employment of self-compacting concrete, which can be compacted into every corner of a formwork, purely by means of its own weight and without the need for vibrating compaction (Fig. 1). The necessity of this type of concrete was proposed by Okamura in 1986. Studies to develop self-compacting concrete, including a fundamental study on the workability of concrete, have been carried out by Ozawa and Maekawa at the University of Tokyo [1].
The prototype of self-compacting concrete was first completed in 1988 using materials already on the market (Fig. 2). The prototype performed satisfactorily with regard to drying and hardening shrinkage, heat of hydration, denseness after hardening, and other properties
[1] [2]. This concrete was named “High Performance Concrete.” and was defined as
References: Paisley, 1993. [7] Nagamoto, N., and Ozawa, K. Mixture proportions of self-compacting high performance concrete, ACI International SP-172, pp.623-636, 1997. [8] Ouchi, M & Edamatsu, Y. A Simple evaluation method for interaction between coarse aggregate and mortar particles in self-compacting concrete, Transaction of JCI, 2000.