Describing the rheology of vibrated, no-slump concrete for application in 3D-printing construction
type: CreativeWork
description: Using an automated process like 3D printing in concrete construction could improve safety and performance while decreasing environmental impact and cost. But 3D-printed concrete construction still needs considerable development before it will be reliable. This research addresses the challenge of extruding concrete, which must be fluid enough to flow through an extruding nozzle but solid enough to retain its shape when placed in layers. It focuses on controlling the fluid/solid state of the concrete with vibration. In rheological literature, vibration has been shown to overcome the yield stress of granular suspensions, permitting them to behave as solids at low strain rates. Most models describe two regimes, one describing Newtonian behavior at low strain rates and the second describing a return to the original, non-vibrated behavior at higher strain rates. Concrete can be considered a volume of aggregates suspended in cement paste and therefore a granular suspension. Several constitutive models have been proposed to describe the rheological behavior of vibrated granular suspensions but only on idealized fluids and at small scales. This study investigated how well these models apply to granular suspensions using concrete constituents. The first series of tests were conducted on standard concrete mixtures without vibration. Stress growth tests and flow curve tests using an ICAR (International Center for Aggregate Research) rheometer and the slump test was conducted on each mixture. The ICAR rheometer was not capable of characterizing no- and low-slump concrete mixtures. It was found that the yield stress of concrete relies on the granular phase while the viscosity relies on the cement paste phase. Because of this, the aggregate stock must be controlled more carefully than is currently done in practice. The second series of tests were conducted on no-slump concrete mixtures made of a bleed-resistance cement paste and coarse limestone aggregates. The gradation was contr…
abstract: Using an automated process like 3D printing in concrete construction could improve safety and performance while decreasing environmental impact and cost. But 3D-printed concrete construction still needs considerable development before it will be reliable. This research addresses the challenge of extruding concrete, which must be fluid enough to flow through an extruding nozzle but solid enough to retain its shape when placed in layers. It focuses on controlling the fluid/solid state of the concrete with vibration. In rheological literature, vibration has been shown to overcome the yield stress of granular suspensions, permitting them to behave as solids at low strain rates. Most models describe two regimes, one describing Newtonian behavior at low strain rates and the second describing a return to the original, non-vibrated behavior at higher strain rates. Concrete can be considered a volume of aggregates suspended in cement paste and therefore a granular suspension. Several constitutive models have been proposed to describe the rheological behavior of vibrated granular suspensions but only on idealized fluids and at small scales. This study investigated how well these models apply to granular suspensions using concrete constituents. The first series of tests were conducted on standard concrete mixtures without vibration. Stress growth tests and flow curve tests using an ICAR (International Center for Aggregate Research) rheometer and the slump test was conducted on each mixture. The ICAR rheometer was not capable of characterizing no- and low-slump concrete mixtures. It was found that the yield stress of concrete relies on the granular phase while the viscosity relies on the cement paste phase. Because of this, the aggregate stock must be controlled more carefully than is currently done in practice. The second series of tests were conducted on no-slump concrete mixtures made of a bleed-resistance cement paste and coarse limestone aggregates. The gradation was contr…
author: Hawkins, Kathleen Adelle
language: en
keywords: concrete rheology, 3D printing, vibrated concrete
date published: 2018-09-27T16:17:55Z
date modified: 2026-07-22T22:24:40Z
provider: University of Illinois - Urbana-Champaign
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Illinois at Urbana-Champaign

PropertyValue
property ID: Handle
value: http://hdl.handle.net/2142/101598