Concrete is the most used material in constructions in the world. Its main characteristic is to support loads resisting compression efforts. However, this property is not sufficient in some specific applications. In the case of structures with a high rate of reinforcement, complex shapes, works with exposed concrete finishing and concrete parts with unconventional formats, in addition to strength, characteristics such as fluidity, cohesion and resistance to segregation are required. As a result, Self-compacting Concrete was produced in Japan, where its high strength and workability in the fresh state made it possible to meet dense meshes and fill any empty space. Self-compacting concrete has eliminated the densification process in works with high reinforcement rates, reducing noise from vibration, increasing the productivity rate and ensuring the excellent surface finish of the parts. Because of this, the precast industry is one of the main users of this type of concrete. At Sendi Pré-Fabricados it is used in the manufacture of various parts, such as pillars, beams, stairs and purlins. The manufacture of self-compacting concrete tries to make it more fluid, working with a line where the amount of coarse aggregate is smaller and using superplasticizers in the composition. ABNT NBR 15823-1:2017 is the standard that establishes requirements for classification, control, receipt, establishes limits and prescribes tests to verify the properties of self-compacting concrete.
By Letícia Lambertini C. Pereira Civil Designer at Sendi