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Feasibility Study of 3D Printing of Concrete for Transportation Infrastructures

Project Details
STATUS

In-Progress

PROJECT NUMBER

TR-756

START DATE

09/15/18

END DATE

09/30/19

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, CP TECH
SPONSORS

Iowa Department of Transportation
Iowa Highway Research Board

Researchers
Principal Investigator
Kejin Wang

PCC Engineer, CP Tech

About the research

There is a growing interest in 3D concrete printing worldwide. Through automation, digitization, and process planning, 3D printing technology permits to create concrete structures having complex geometry (various shapes/cross-sections) with high precision. It also enables concrete construction under extreme conditions that are difficult and/or very costly for conventional concrete form-work setup, placing, and/or consolidation. Many breakthroughs have been made in 3D concrete printing already, and one of them is the recent development in printing of reinforced concrete, which has opened a new door for further innovations and applications of 3D printed concrete.

In spite of significant progress of this technology, studies on 3D concrete printing for the applications in transportation infrastructures are still very limited. This project will explore the feasibility to fill this gap. Research has indicated that in addition to the proper printing equipment and automation design tools, a core for successful 3D printed concrete is to have a desirable robust “ink”, or an engineered concrete mixture. The focus is to develop a printable, functional concrete mixture. The investigators will conduct a throughout literature review on 3D concrete printing technology, covering from 3D printing methods and equipment to materials, processes, and characterizations of printed products. Based on the review results, a laboratory scale concrete printer will be selected to be purchased or built. The equipment will be used to study selected mixes, which will be designed according to the literature and investigators’ experiences, and to print small-scale concrete elements (e.g., circular/square columns and deck bulb tee girders that have a potential to make bridge constructions more cost effective). The engineering properties (e.g., printability, flowability, buildability, open time and layer adhesiveness) of these printed elements will be evaluated, and the key mix design parameters that significantly affect features of 3D printed concrete will be identified.

Based on the identified parameters and their effects on printing properties, a small group of 3D printing concrete mix candidates (2-3 mixes) will be further modified to optimize their properties. If time permits, feasibility of printing more complex shaped girders will be explored, and structural behaviors (e.g., strain-strain behaviors under compression and flexural loading) of selected printed-concrete elements will be further studied. It is expected that this exploratory study will bring many 3D printing related innovations to Iowa and offer a revolutionary perspective on the future structural concrete design and construction of transportation infrastructures as well as on emergency road/bridge repairs.

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