Aggregation and Self-Compaction of Concrete

Abstract

Self-compacting concrete technology (SCC) is a new concept in concreting technology which offers good placement of the mixture, removing the compulsory phase of vibration. The advantages are: ease of operation of a heavy task, best finish of the surfaces, concrete faster, less noise pollution, savings in personnel and equipment, excellent quality concreted elements. In addition to the above advantages, self compacting concrete allows for high resistance short-and long-term, low water/cement ratio, high impermeability and durability. To achieve these properties always desired, now companies must resort to complex formulations and often costly, requiring, in any case, the obligation of a powerful vibration to ensure optimal filling of the formwork. The vibration operation often leaves no concrete fully consolidated, especially in thin elements, heavily armed or complicated shapes. Furthermore, vibration, in most cases, results in a high noise level and may cause serious illness to operators. The vibration also causes wear and exerted strong pressure on the molds. On the other hand, a mismatch occurs due to vibration segregation in concrete. In the precast industry as products become more complex and requires more fluid and more energetic vibration. Both needs are expensive and, depending on the complexity of manufactured items are not always achieve the desired results. SCC is a mixture which may be consolidated within each corner of a shuttering only through its own weight and without the necessity of compacting vibration. Despite its high fluidity, the coarse aggregate is not secreted. In order to make concrete which is self compacting standardized and a regular type of concrete, investigations will be carried out for methods of testing for self compatibility and for the establishment of a method of mix design that is rational. This paper is aimed at analyzing aggregation and self compaction of concrete, and will look to shed light on the existing literature on the topic.

Aggregation and Self-Compaction of Concrete

Introduction

The first investigations for concrete which is self compacting began in Japan, looking for concretes that do not depend on the skill of the labor force in vibration to ensure the durability of concrete structures, since they require trained operators to perform the proper compaction of concrete, for obtain a material sufficiently consolidated and therefore, durable in the long term. A reduction in the amount of skilled workers to the concrete vibration means a similar reduction in the quality of the construction. In 1988, at the University of Tokyo, they succeeded in developing the self-compacting concrete. Since then he has conducted extensive research in various institutions and companies that have allowed for several years, the practical application in the works of this new technology which aims to become the future standard in a concrete rather than a special concrete (Ozawa et al, 1999).

To date, there have been a large number of applications for a wide variety of structures and concrete elements, including floors and slabs, modular elements of only a few centimeters thick, pre-stressed beams and other elements, heavily armed walls in houses buildings and ...