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 October 2024 is Alberto Castillo , a PhD student in Civil and Construction Engineering at Purdue University (West Lafayette, USA).
BIO:
Alberto Castillo is a Ph.D. candidate in Civil and Construction Engineering at Purdue University, working under the supervision of Prof. Jan Olek and Prof. Mirian Velay-Lizancos. He holds both a bachelor’s degree in Civil Engineering and a Master of Science in Civil Engineering from Purdue University. Alberto’s research interests focus on improving the sustainability, durability, and performance of construction materials, particularly cementitious materials. His work includes promoting the use of nontraditional and natural pozzolans by showcasing their effectiveness, enhancing concrete properties with nanomaterials, and improving concrete’s overall durability.
TITLE:
Field Performance of Natural Pozzolans in Concrete for Pavement Applications
There is a degree of uncertainty regarding the ability of traditional supplementary cementitious materials (SCMs) to meet the future needs of the construction sector economically. In response, natural pozzolans (NPs) are emerging as viable alternatives in the western US due to their relative abundance there. These materials also contribute to lowering the environmental footprint of cement manufacturing, making them viable for sustainable construction. Although previous studies have shown the satisfactory performance of concretes with NPs under laboratory conditions, research on their effectiveness in real-world applications remains limited. Furthermore, direct comparisons between the performance of concretes with NPs and concretes with traditional SCMs, like fly ash, remain largely unexplored. The objective of this research is to address these knowledge gaps by investigating the mechanical and durability properties of concrete extracted from slabs exposed to field conditions.
In this study, several concrete mixtures were developed. All of them were designed in accordance with the Indiana Department of Transportation (INDOT) standard specifications for Portland Cement Concrete Pavements (PCCP). Type IL cement was used, and a constant water-to-cementitious material ratio (w/cm) of 0.44 was maintained. The mixtures were produced at a commercial ready-mixed concrete plant.
The NPs used in the mixtures belonged to two distinctive groups of materials: low-purity calcined clays (CC2), and volcanic ashes (VA2, and VA3), with NPs replacing 25% of cement by weight. In addition to NP mixtures, the study also included a reference mixture (Type IL cement only) and mixtures where 20% and 25% of the cement was replaced by fly ash as an SCM. The air content of all freshly mixed concretes was maintained within the range of 7.0 +/- 1.5%.
Once manufactured, the mixtures were used to cast six concrete slabs, each measuring 8 ft x 8 ft x 10 in, which were placed outdoors near Indianapolis, IN. The same concrete mixtures used to construct the slabs were also used to cast several 4 x 8 in cylinders, which were stored alongside the slabs in the field for the first 24 hours before being moved to the lab, where they were subjected to standard wet curing. Throughout the study, internal temperatures within the slabs and changes in the visual appearance of the surfaces of the slabs were monitored over a period of 1 year of outdoor exposure. Periodically, at the age of 7, 28, 56, 90, and 365 days after casting, several 4 in x 8 in cores were extracted from the slabs and transported to the lab for further testing. Both cast and cored concrete specimens were tested for mechanical properties, including compressive, split tensile, and flexural strength, as well as durability-related properties such as rate of water absorption, formation factor, chloride penetration depth, and scaling resistance.
The test results indicate that concrete containing NPs performed as well as, or better than, concretes containing fly ash and was comparable to cement-only concrete. As an example, concretes with NPs exhibited higher late-age (i.e. 56 days and beyond) compressive strength than fly ash concretes, and their strength was comparable to the strength of the reference concrete. In terms of flexural strength, concretes with VA3 met the minimum threshold of 570 psi required by INDOT’s specifications for opening pavements to traffic. Concretes with VA2 and CC2, as well as those with fly ash, were close to this limit. Reducing the air content of these mixtures by approximately 1% will likely ensure they meet the required threshold. Regarding durability, concrete with NPs generally exhibited equal or improved performance compared to the reference mixture in terms of rate of water absorption, formation factor, and chloride penetration depth. Although specimens with NPs had slightly lower scaling resistance than the reference and fly ash mixtures, their mass losses were still below the 0.8 kg/m2 threshold set by the Ministry of Transportation of Ontario (MTO) as an indicator of adequate scaling resistance. Overall, these findings suggest that NPs are promising alternatives for future concrete applications.
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/
MARCH 2023: Sinan Kefeli, Ph.D. Candidate, Department of Civil and Environmental Engineering, Iowa State University (Ames, USA): https://www.concretepavements.org/2023/03/13/student-research-spotlight-march-2023/
APRIL 2023: Niwesh Koirala, Ph.D. Candidate, Department of Civil and Environmental Engineering, Texas Tech University (Lubbock, USA): https://www.concretepavements.org/2023/04/07/student-research-spotlight-april-2023/
MAY 2023: Christian A. Sabillon, Ph.D. Candidate, The University of Texas at Austin (Austin, Texas, USA): https://www.concretepavements.org/2023/05/05/student-research-spotlight-may-2023/
JUNE 2023: Saima Yaqoob, Ph.D. Candidate, KTH (the Royal Institutes of Technology) (Stockholm, Sweden): https://www.concretepavements.org/2023/06/15/student-research-spotlight-june-2023/
JULY 2023: Ricardo Hungria, Ph.D. Candidate, Louisiana State University (Baton Rouge, USA): https://www.concretepavements.org/2023/07/11/student-research-spotlight-july-2023/
AUGUST 2023: Megan Darnell, Ph.D. Candidate, University of Pittsburgh (Pittsburgh, USA): https://www.concretepavements.org/2023/08/07/student-research-spotlight-august-2023/
SEPTEMBER 2023: Jitendra Patel, Ph.D. Candidate, Alma Mater Studiorum – Università di Bologna (Italy): https://www.concretepavements.org/2023/09/05/student-research-spotlight-september-2023/
OCTOBER 2023: Omar K. Omar, Ph.D. Candidate, Louisiana State University (Baton Rouge, USA): https://www.concretepavements.org/2023/10/05/student-research-spotlight-october-2023/
NOVEMBER 2023: Mason Smetana, Ph.D. Candidate, University of Pittsburgh (Pittsburgh, USA): https://www.concretepavements.org/2023/11/07/student-research-spotlight-november-2023/
DECEMBER 2023: Avinash Jha, M.Tech Student, Indian Institute of Technology Gandhinagar (India): https://www.concretepavements.org/2023/12/10/student-research-spotlight-december-2023/
JANUARY 2024: Matthew Sheffield, Ph.D candidate, University of North Carolina at Charlotte (Charlotte, USA): https://www.concretepavements.org/2024/01/13/student-research-spotlight-january-2024/
FEBRUARY 2024: Chintada Chandrasekhar, Ph.D candidate, Indian Institute of Technology Roorkee (Roorkee, India): https://www.concretepavements.org/2024/02/08/student-research-spotlight-february-2024/
MARCH 2024: Subham Jain, Ph.D candidate, Indian Institute of Technology Kanpur (Kanpur, India): https://www.concretepavements.org/2024/03/08/student-research-spotlight-march-2024/
APRIL 2024: Etienne Beya Nkongolo, Ph.D candidate, University of Missouri Kansas-City (Kansas City, USA): https://www.concretepavements.org/2024/04/11/student-research-spotlight-april-2024/
MAY 2024: Shivani Sharma, Ph.D candidate, Indian Institute of Technology Gandhinagar (Gandhinagar, India): https://www.concretepavements.org/2024/05/14/student-research-spotlight-may-2024/
JUNE 2024: Isaac Oyawoye, Ph.D candidate, University of North Carolina at Charlotte (Charlotte, USA): https://www.concretepavements.org/2024/06/16/student-research-spotlight-june-2024/
JULY 2024: Tianzhen Li, Ph.D candidate, Xi’an Jiaotong-Liverpool University and the University of Liverpool (Suzhou, China): https://www.concretepavements.org/2024/07/04/student-research-spotlight-july-2024/
AUGUST 2024: Andrés Gabriel César Torres, Ph.D candidate, Polytechnic School of the University of São Paulo (São Paulo, Brazil): https://www.concretepavements.org/2024/08/06/student-research-spotlight-august-2024/
SEPTEMBER 2024: Bhabya Thakur, Masters student, Indian Institute of Technology Gandhinagar (Gandhinagar, India): https://www.concretepavements.org/2024/09/21/student-research-spotlight-september-2024/