Civil Engineering ETDs

Publication Date

Fall 9-24-2021

Abstract

Additive manufacturing technology has been established as one of the fastest-growing building technologies worldwide. Three-dimensional concrete printing (3DCP) has developed an increasing interest in the last decade due to its prospects as a transformative technology for industries such as the concrete precast. Besides the improvements in automation technologies in construction, traditional construction has faced considerable challenges: high accident rates, labor dependency, significant potential for automation, and high costs associated with the use of traditional formwork. In this context, three-dimensional concrete, also referred to as physical prototyping, is a novel construction technique in which the concrete is extruded layer-to-layer. 3DCP is positioning itself as an alternative to conventional fabrication processes under specific circumstances such as complex geometries, expensive workforce, and high automation requirements.

Furthermore, labor investment in the building industry has decreased over the last decades, which places this technology in an advantageous place. Concrete is the most globally consumed material for construction applications due to its competitive cost, worldwide availability of the raw components, good mechanical properties, longevity, and ability to remain fluid before hardening. Cementitious materials present some inherent limitations, such as time-variable rheological properties or low tensile strength, among others. As a consequence of the deposition nature of 3DCP, an anisotropic mechanical behavior has been reported in the literature. This work examines the significance of infill printing patterns on the anisotropic properties of 3D printed concrete.

Polymer concrete (PC) is a type of concrete in which a polymer entirely replaces the cementitious binder. It has been widely used in the construction industry since 1970, offering some advantages such as manufacturing simplicity, remarkable mechanical properties in both compression and tension behavior, low curing time, low permeability, and superior bond between different layers of the same material and to different substrates. Many characteristics make PC a good alternative for the additive manufacturing industry. Research work has been performed to characterize cement-based concrete for additive manufacturing. However, the use of PC in 3D printing is still yet to be examined. This study aims to investigate the potential use of PC for 3D printing for infrastructure applications.

Textile reinforced concrete (TRC) has gained attention from the construction industry due to its lightweight, high tensile strength, design flexibility, and corrosion resistance with remarkably long service life. Structural applications that utilize TRC components include precast panels, structural repair, waterproofing elements, and façades. TRC is produced by incorporating multiple textile fabrics into thin cementitious concrete panels. In this thesis, innovative reinforcement techniques such as interlayer textile reinforcement are explored for both cement and polymer-based 3D printing materials.

Finally, the level of maturity of 3DCP as an emerging technology is examined. The potential of 3DCP as a technology to improve infrastructure resilience is investigated.

Keywords

Additive manufacturing, Concrete 3D-Printing, 3D-Printing anisotropy, 3D-Printing reinforcement

Document Type

Dissertation

Language

English

Degree Name

Civil Engineering

Level of Degree

Doctoral

Department Name

Civil Engineering

First Committee Member (Chair)

Mahmoud Reda Taha

Second Committee Member

John Stormont

Third Committee Member

Maryam Hojati

Fourth Committee Member

Kamal H. Khayat

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