Properties and use of self- compacting concrete

Abstract

Self-Compacting Concrete is defined as a concrete that has a significantly high flowability, with notable resistance to segregation during transport and placement, it can be poured inside narrow formwork and high density reinforcing bar arrangement without applying vibration. This new concrete type was developed at the end of the eighty and it has been used in the practice in different types of structures, especially in big works, taking the advantages of a technology that avoids the heavy task of vibration in the construction with concrete. In Chile, the technology of the Self-Compacting Concrete together with the chemical admixtures that are used in this concrete, started to be introduced at the beginning of the 2000. The main properties of interest in their fresh state are flowability and segregation resistance. A high flowability as well as a high viscosity in the Self-Compacting Concrete is obtained with an appropriate design of the mixture and using an Ultra High Range Water Reducer (UHRWR) admixture. The properties of Self-Compacting Concrete in hardened state are similar or superiors to those of the traditional vibrated concrete. Self Compacting Concrete is applied in all type of concrete works, either for precast concrete elements, industrial floors, tanks, bridges, dams, tunnels, walls, columns and slabs in buildings. In this article this new technology and its advantages are described, examples of big works constructed with Self Compacting Concrete are mentioned, together with the tests that are carried out to verify the main properties and the considerations of design of this new concrete type.