Changes in Rheology of Self-Consolidating Concrete Induced by Pumping

Abstract

Pumping is an easy and flexible process to place concrete inside a formwork. Many studies have recently been performed to understand and optimize the pumping process and identify the main differences between pumping of conventional vibrated concrete and self-consolidating concrete (SCC). However, due to pumping, changes in fresh concrete properties and the air-void system have been noticed. This paper describes the consequences of pumping on the fresh properties of SCC by means of two experimental pumping campaigns. In many cases, the concrete undergoes a large shear rate in the pipe, thus (re-)dispersing cement particles. This is expected to be the main cause of the observed decrease in plastic viscosity, V-Funnel flow time and pumping pressure resulting from increased flow rate or pumping time. The changes in yield stress or slump flow are anticipated to be influenced by the same phenomenon, but the final outcome is assumed to depend on the availability of residual superplasticizer in the mixing water. Pumping can cause a stable SCC to become segregating if both the yield stress and plastic viscosity decrease, or it can provoke a significant loss in filling ability, passing ability and self-consolidation of the concrete if the yield stress increases dramatically.

Department(s)

Civil, Architectural and Environmental Engineering

Keywords and Phrases

Concretes; Elasticity; Optical pumping; Rheology; Viscosity; Yield stress; Air-void systems; Filling abilities; Flexible process; Fresh properties; Plastic viscosity; Self-consolidating concrete; Superplasticizers; Vibrated concretes; Pumps; Pumping

International Standard Serial Number (ISSN)

1359-5997

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2016 Kluwer Academic Publishers, All rights reserved.

Publication Date

01 Nov 2016

Link to Full Text

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