Identifying the best mixing procedure practice for ready-mix concrete plant production of carbon fibre reinforced electrically conductive concrete

ABSTRACT

Electrically-conductive concrete (ECON) can generate heat for melting pavement ice if an electrical voltage is applied, and this ECON-heated pavement system (HPS) is a viable alternative to the traditional snow removal methods. This study aimed at determining mixture proportions and procedures suitable for ready-mix concrete-plant-produced carbon fibre (CF)-reinforced ECON. Trial batches ECON production involving five different mixture proportions and procedures were performed at a ready-mix concrete plant. Study results suggest that CF begins to degrade with increased mixing time. A twelve-minute mixing time from the start of loading CF onto the mixer until the end produced the best-performing ECON, with an electrical resistivity of 224 Ω-cm and a heat-generation rate of 2°C/min. Scanning electron microscopic (SEM) image analysis shows that CF remained as blobs of fibre instead of being uniformly dispersed. Further research is recommended to find an efficient way of separating individual CF from the blobs and ensuring uniform CF dispersion to reduce the dosage rate and construction cost of ECON.

KEYWORDS:

• Electrically conductive concrete
• Carbon fibre
• Ready-mix concrete
• Resistive heating

Acknowledgments

The authors would like to thank the Iowa Department of Transportation (DOT) and the Iowa Highway Research Board (IHRB) for providing the matching funds for this research study. The authors would also like to thank the FAA Air Transportation Center of Excellence for the Partnership to Enhance General Aviation Safety, Accessibility, and Sustainability (PEGASAS). The IHRB technical advisory committee (TAC) members from Iowa DOT, Iowa Counties, City of Iowa City, and Iowa Concrete Paving Association (ICPA), the FAA PEGASAS Technical Monitors for Heated Airport Pavements project, and Mr. Gary L. Mitchell of the American Concrete Pavement Association (ACPA) are gratefully acknowledged for their guidance, support, and direction throughout the research. The authors would also like to express their sincere gratitude to including, but not limited to, the Iowa City officials, staff from All American Concrete Inc., the Croell Inc. ready-mix concrete plant staff, the Zoltek, the Materials Analysis and Research Lab staff at Iowa State University (ISU), and other research team members from the ISU Program for Sustainable Pavement Engineering and Research (PROSPER) at the InTrans for their assistance in this research study. Although the IHRB, Iowa DOT, and FAA have sponsored this study, they neither endorse nor reject any comments made in this paper. The presentation of this information is in the interest of invoking comments by the technical community concerning the results and conclusions of the research. This paper does not constitute a standard, specification, or regulation.

Disclosure statement

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Halil Ceylan and Sunghwan Kim are co-founders of Heated Pavements, Inc., a start-up company with business interests in commercializing heated pavement system technologies based on the Intellectual Property license from the Iowa State University Research Foundation (ISURF) beyond their academic appointments at Iowa State University. No other author has declared a potential conflict of interest.

Additional information

Funding

This work was supported by U.S. Department of Transportation: [Grant Number GR-022546-00001].