Fiber orientation effects on ultra-high performance concrete formed by 3D printing

This paper studied the influence of fiber volume fraction ( V f ), fiber orientation, and type of reinforcement bar (rebar) on the uniaxial tensile behavior of rebar-reinforced strain-hardening ultra-high performance concrete (UHPC). It was observed that the tensile strength increased with the increase in V f . When V f was kept constant at 1%, rebar-reinforced UHPC with fibers aligned with the load direction registered the highest strength and that with fibers oriented perpendicular to the load direction recorded the lowest strength. The strength of the composite with random fibers laid in between. Moreover, the strength, as well as the ductility, increased when the normal strength grade 60 rebars embedded in UHPC were replaced with high strength grade 100 rebars with all other conditions remaining unchanged. In addition, this paper discusses the potential of sudden failure of rebar-reinforced strain hardening UHPC and it is suggested that the composite attains a minimum strain of 1% at the peak stress to enable the members to have sufficient ductility.

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Fiber Orientation in Ultra-High-Performance Concrete Shear Keys of Adjacent-Box-Beam Bridges

ACI Materials Journal ◽

10.14359/51701097 ◽

2018 ◽

Vol 115 (2) ◽

Cited By ~ 1

Author(s):

Kenneth K. Walsh ◽

Nathan J. Hicks ◽

Eric P. Steinberg ◽

Husam H. Hussein ◽

Ali A. Semendary

Keyword(s):

Fiber Orientation ◽

High Performance ◽

High Performance Concrete ◽

Ultra High Performance Concrete ◽

Box Beam ◽

Shear Keys

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Effect of Fiber Orientation on Dynamic Compressive Properties of an Ultra-High Performance Concrete

10.37099/mtu.dc.etdr/163 ◽

2016 ◽

Author(s):

Andrew B. Groeneveld

Keyword(s):

Fiber Orientation ◽

High Performance ◽

High Performance Concrete ◽

Compressive Properties ◽

Ultra High Performance Concrete

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3D-Printing of Ultra-High-Performance Concrete for Robotic Bridge Construction

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/03611981211011645 ◽

2021 ◽

pp. 036119812110116

Author(s):

Ali Javed ◽

Islam M. Mantawy ◽

Atorod Azizinamini

Keyword(s):

3D Printing ◽

High Performance ◽

New Technologies ◽

Performance Metrics ◽

High Performance Concrete ◽

Research Effort ◽

Advanced Materials ◽

Ultra High Performance Concrete ◽

Bridge Construction ◽

Heat Curing

Automation and robotics are integral parts of many industries but their potential for field implementation has not been significantly recognized by the construction industry. This is mainly attributed to conventional construction and design practices which undermine the benefits offered by these new technologies such as repetitions, precision, time savings, and increased safety. There is a need for advanced materials and 3D-printing systems which are capable of constructing structural elements with performance that emulates conventionally cast elements. This study presents a detailed framework and performance metrics for materials and 3D-printing systems for bridge applications. In addition, a study was carried out on ultra-high-performance concrete (UHPC) which showed sufficient extrudability and workability for 3D-printing applications. A 3D-printing system was developed for 3D-printing of continuous additive layers of UHPC with accelerated heat curing. Accelerated heat curing was used to enhance buildability, expedite the printing of the UHPC layers, and maximize the number of printed layers within the material open time. The effect of heat curing on material properties was also evaluated to obtain the optimal temperature to satisfy compressive strength requirements. This research effort aims to augment automated construction techniques and develop solutions to extend the applications of accelerated bridge construction.

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