Influence of segregation on the performance of self-compacting concrete in the fresh and hardened states

Moulaï Abdellah Bouabdallah,Rachida Mohammed Krachaï

doi:10.34118/jbms.v7i2.768

Abstract

The granular mixture represents one of most important parameters in the formulation of self-compacting concretes in order to achieve a representative granular distribution. A good resistance to segregation results in a regular distribution of the different sizes of the aggregates in all parts of the element, with the same granule density. The granular mixture must be homogeneous and representative, and has to be able to flow in the absence of dynamic and static segregation.The main objective of the present research is to study the influence of segregation on the performance of Self-compacting concrete in the fresh and hardened state, by determining the static segregation index according to the percentage of aggregates of class G 8/15 and that of aggregates of class G 3/8 in order to obtain a homogeneous granular mixture, whatever the volume of self-compacting concrete to be prepared. It is well acknowledged that the threshold of the discontinuation of granular mixing represents a new element with respect to segregation in concrete. The obtained results showed that the percentage of large aggregates has a significant influence on the segregation index and the performance of self-compacting concrete (SCC) at 28 days.

Highlights

Self-compacting concretes are hyper-fluid concretes that can be placed, without vibration, under the effect of their own weight and because of their flow characteristics
The main objective of the present research is to study the influence of segregation on the performance of Self-compacting concrete in the fresh and hardened state, by determining the static segregation index according to the percentage of aggregates of class G 8/15 and that of aggregates of class G 3/8 in order to obtain a homogeneous granular mixture, whatever the volume of self-compacting concrete to be prepared
The behavior of the concretes tested varied with (SSI (%) < 5) which ensures that these concretes have a sufficient spread so they can be classified as selfcompacting concretes, according to the French Standard NF 206

Summary

Introduction

Self-compacting concretes are hyper-fluid concretes that can be placed, without vibration, under the effect of their own weight and because of their flow characteristics. These concretes must have a high fluidity and be able to flow with a sufficient flow rate, without external energy supply, through confined areas even in the presence of obstacles; they can be placed in tall formworks. The formulation of self-compacting concrete is based on three criteria, i.e. fluidification of concrete paste, limitation of friction between the aggregates in order to promote the flow and stabilization of the mixture, and prevention of segregation in concrete

Objectives

Results

Conclusion