STUDENT SPOTLIGHT: Each month, or every other month, a student will provide a 1-page illustrated abstract of the research they are currently conducting. This is a wonderful opportunity for the student, for our International Society for Concrete Pavements (ISCP) Members, and for the transferring and sharing technology/research through our concrete paving industry.
The ISCP “STUDENT RESEARCH SPOTLIGHT” for March 2023 is Sinan Kefeli, a Ph.D. student in civil engineering at Iowa State University (Ames, USA).
BIO:
Sinan Kefeli is a Ph.D. candidate in Civil Engineering at Iowa State University (ISU), where he co-specializes in Civil Engineering Materials and Intelligent Infrastructure Engineering. He also works as a graduate research and teaching assistant under the supervision of Prof. Dr. Halil Ceylan and Prof. Dr. Peter Taylor. Sinan’s research examines the effects of varying aggregate mineralogy, morphology, and gradation on concrete workability, mechanical, and durability properties. Paste-to-voids volume ratio in concrete mixtures, Tarantula curve for gradation with different aggregate systems, utilizing the VKelly Ball Test for workability, air-void systems in concrete mixtures, reduction in cementitious materials and carbon footprint, developing predictive methods (i.e., artificial intelligence/machine learning (AI/ML) and statistical) for determining concrete properties and mixture variables can be listed as his main research areas.
He received his bachelor’s and master’s degrees at Middle East Technical University (Ankara, Turkiye) and Cankaya University (Ankara, Turkiye) in civil engineering, respectively. Before joining the Ph.D. program at the Department of Civil, Construction and Environmental Engineering and National Concrete Pavement Technology Center (CP Tech Center) at ISU, he served in the industry in various positions such as assistant lab manager and site manager. He is currently the president of the American Concrete Institute (ACI) Student Chapter at ISU. He helps Prof. Dr. Halil Ceylan teach the Design of Concretes as a teaching assistant in the spring semesters.
TITLE:
Effects of Aggregate Shape and Morphology on Gradation and Proportioning Requirements for Concrete Mixtures
The fresh and hardened properties of concrete could be targeted by proportioning the concrete mixtures. Workability, transport, strength, cold weather properties, shrinkage, and aggregate stability are the most relevant mechanical and durability concrete properties. In order to obtain the desired concrete mixture having the desired workability, the aggregate gradation should be optimized due to the varying aggregate shape and morphology. The Tarantula Curve is a convenient tool to adjust and represent the individual aggregate gradation and combine aggregate system gradation.
Figure 1: Super Air Meter (SAM) for air-void system
Figure 2: Gradations of different combined aggregate systems on Tarantula Curve
While gradation is monitored with the Tarantula curve, this main changing effect on the mixture could be observed with the VKelly Ball test to quantify the workability of fresh concrete. The VKelly Ball Test is a method that can measure the workability of concrete as a Bingham fluid having two parameters: yield stress and viscosity, simulating the vibration effect of slipformed pavers.
Figure 3: Example VKelly Index plot
Concrete mixtures can be optimized with quite a number of parameters, including aggregate source, shape, morphology, paste volume, paste-to-voids volume ratio, water-to-cementitious materials ratio, air content, supplementary cementing materials (SCMs) type and replacement ratio. With the abovementioned parameters, the needs of the projects can be met without compromising the must-have properties while ensuring that the durability and mechanical properties are enhanced.
This graduate study covers many trial and final batches to provide sufficient data to provide conclusions affecting concrete performance. The original data obtained from the experimental matrix is also used to develop predictive methods (i.e., artificial intelligence/machine learning (AI/ML) and statistical) for determining concrete properties and mixture variables such as the VKelly index, paste-to-voids volume ratio and compressive strength. Besides the statistical regression models, artificial neural networks (ANN) and metaheuristic algorithms are within the scope of the research.
ISCP would like to feature a “STUDENT RESEARCH SPOTLIGHT” each month, or every other month. If you would like to nominate a student, or if you are a student and would like to nominate yourself or a colleague, please send ISCP an email to: newsletter@concretepavements.org
ALL SPOTLIGHTS:
DECEMBER 2021—Inaugural: Katelyn Kosar, Phd Student-Department of Civil and Environmental Engineering, University of Pittsburgh (Pitt): www.concretepavements.org/2021/12/14/new-at-iscp-student-research-spotlight/
JANUARY 2022: Aniruddha Baral, Ph.D. Candidate-Department of Civil and Environmental Engineering, University of Illinois-Urbana-Champaign: www.concretepavements.org/2022/01/15/student-research-spotlight-jan-2022/
FEBRUARY 2022: Jordan Ouellet, Tech, BEng, MASc, PhD Candidate, Teaching and Research Assistant, University of Illinois at Urbana-Champaign: www.concretepavements.org/2022/02/26/student-research-spotlight-february-2022/
MARCH 2022: Sampath Kumar Pasupunuri, Ph.D. candidate, Pavement Engineering-School of Civil Engineering, University of Nottingham, UK: https://www.concretepavements.org/2022/03/31/student-research-spotlight-march-2022/
APRIL 2022: Anupam B R, Pursuing his doctorate-Indian Institute of Technology Bhubaneswar, India: https://www.concretepavements.org/2022/04/15/student-research-spotlight-april-2022
MAY 2022: Andréia Posser Cargnin, Ph.D. Candidate, Polytechnic School, University of São Paulo (São Paulo, Brazil): https://www.concretepavements.org/2022/05/09/student-research-spotlight-may-2022/
JUNE 2022: Charles Donnelly, Ph.D. Candidate, Department of Civil and Environmental Engineering, University of Pittsburgh (Pittsburgh, USA): https://www.concretepavements.org/2022/06/24/student-research-spotlight-june-2022/
JULY 2022: Amir Malakooti, Ph.D. Candidate, Department of Civil and Environmental Engineering, Iowa State University (Ames, Iowa, USA): https://www.concretepavements.org/2022/07/30/student-research-spotlight-july-2022/
AUGUST 2022: Haoran Li, Ph.D. Candidate, Department of Civil and Environmental Engineering, University of Pittsburgh (Pittsburgh, USA): https://www.concretepavements.org/2022/08/24/student-research-spotlight-august-2022/
SEPTEMBER 2022: Sumit Nandi, Ph.D. Candidate, Department of Civil Engineering, Indian Institute of Technology Roorkee (Roorkee, India): https://www.concretepavements.org/2022/09/18/student-research-spotlight-september-2022/
OCTOBER 2022: Eric Ribeiro da Silva, Ph.D. Candidate, Department of Civil Engineering, Polytechnic School of the University of São Paulo (São Paulo, Brazil): https://www.concretepavements.org/2022/10/20/student-research-spotlight-october-2022/
NOVEMBER 2022: Zachary Brody, Ph.D. Candidate, Department of Civil and Environmental Engineering, University of Pittsburgh (Pittsburgh, USA): https://www.concretepavements.org/2022/11/18/student-research-spotlight-november-2022/
DECEMBER 2022: Jesús Castro Pérez, Ph.D. Candidate, Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign (Urbana, USA): https://www.concretepavements.org/2022/12/17/student-research-spotlight-december-2022/
JANUARY 2023: Dan King, Ph.D. Candidate, Department of Civil and Environmental Engineering, Iowa State University (Ames, USA): https://www.concretepavements.org/2023/01/26/student-research-spotlight-january-2023/
FEBRUARY 2023: Kathryn Kennebeck, Ph.D. Candidate, Department of Civil and Environmental Engineering, University of Pittsburgh (Pittsburgh, USA): https://www.concretepavements.org/2023/02/28/student-research-spotlight-february-2023/