Introducing a New Quantitative Evaluation Method for Segregation of Normal Concrete

In-Deok Han,Dongyeop Han

doi:10.1186/s40069-021-00458-9

Abstract

The aim of this research is to provide a quantitative method for evaluating concrete segregation. Because of various conditions of concrete materials, mix proportions, and delivery, concrete can be segregated. The acquisition inspection executed in construction field for supplied ready-mixed concrete is an important quality control process for concrete. Among the inspections conducted at the project site, segregation of concrete mixture should be evaluated before placing the concrete mixture, currently a qualitative inspection on concrete segregation was conducted. For a normal concrete mixture with slumping behavior, shear slump or collapse slump often occur as an indication of segregation. The suggested evaluation index of segregation for normal concrete (EISN) was induced from the shape of the concrete slumping: relation between the maximum distance of flow and the minimum distance of flow. To evaluate the feasibility of EISN, two different concrete mixture conditions were tested. The recommended EISN parameter of segregation is 1.09 using the three grades of concrete quality. This new quantitative method of evaluating segregation of the concrete mixture is expected to contribute to a more efficient quality control in concrete construction.

Highlights

Because of changing conditions of concrete materials, such as aggregate quality or other supplementary cementitious materials, determining the appropriate concrete mix proportion needed to assure a good mixture consistency is difficult
With a consideration that concrete mixture is a suspension of aggregates within the cement paste (Erdem et al, 2010; Toutou et al, 2007), if the water-to-cement ratio remains the same, the unit water content is a portion of the cement paste
For S/a, S/a is known as controlling the cohesion of the mixture, increasing S/a decreased the slump of the mixtures

Summary

Introduction

Because of changing conditions of concrete materials, such as aggregate quality or other supplementary cementitious materials, determining the appropriate concrete mix proportion needed to assure a good mixture consistency is difficult. The purpose of a concrete mix design is to secure the desirable performance at fresh state and hardened state concrete such as workability, strength, durability, and uniform appearance with acceptable economic advantage. Journal information: ISSN 1976-0485 / eISSN 2234-1315 should have a segregation resistance during the working processes of delivering and placing; unit water content and sand-to-aggregate ratio (S/a) are the representative factors dominating segregation (or uniformity) of the concrete mixture. The unit water content can be considered as a determining factor for workability of the concrete mixture. With a consideration that concrete mixture is a suspension of aggregates within the cement paste (Erdem et al, 2010; Toutou et al, 2007), if the water-to-cement ratio remains the same, the unit water content is a portion of the cement paste. S/a is the ratio of a fine aggregate (sand) volume to the entire aggregate volume within the unit volume (one cubic meter) of the concrete mixture

Objectives

Methods

Results

Conclusion