Abstract: Supplementary cementitious materials (SCMs) are critical for the continued production of sustainable and durable concrete. These materials undergo reactions in concrete with cement hydration products or the cement pore solution. Two types of SCMs, pozzolanic (such as fly ash) and latent hydraulic (such as slag) are generally identified in literature. Due to recent shortfalls of conventional SCMs, there is a growing need to identify and understand the performance of alternative SCM sources. In addition to identifying these SCMs, their behavior in concrete should be understood. In this talk, rapid reactivity testing of SCMs is described, with a major focus on the recently developed “modified R3 test”. In the test, the heat release and calcium hydroxide consumption of SCMs mixed in a 1:3 ratio with calcium hydroxide in a 0.5 M potassium hydroxide solution (liquid: solid ratio 0.9) at 50 °C are measured. The test is promising as it can identify material nature (i.e. inert, pozzolanic, or latent hydraulic) and quantify SCM reactivity. We discuss method development and show reactivity results for several conventional and alternative SCMs. The importance of reaction kinetics is highlighted. The complex effects of temperature, solution composition, and material fineness on reactivity are explored. Preliminary results on the reactivity of synthetic calcium aluminosilicate glasses are discussed. For a smaller subset of materials, links between SCM reactivity and cement paste and concrete properties are presented.
Biography: Prannoy Suraneni is an assistant professor in the Civil and Architectural Engineering Department at the University of Miami since 2017 and the Knight Career Development Assistant Professor since 2022. He obtained his B.Tech., M.S., and Ph.D. degrees in Civil Engineering from IIT Madras, University of Illinois at Urbana-Champaign, and ETH Zurich, respectively. Prannoy is an expert in the materials science, chemistry, and engineering of cementitious materials. He has 14+ years of experience working on these topics, specifically in the areas of supplementary cementitious materials, alternative cementitious materials, and concrete durability. He has published 80+ peer-reviewed international journal papers since 2011, which have received ~1600 citations. He is best known for his contributions towards supplementary cementitious materials reactivity and towards mitigation of calcium oxychloride damage in concrete. He is Editorial Board Member for ASTM Advances in Civil Engineering Materials and Cement and Concrete Research. In the last four years, he has been selected as ASTM Emerging Professional, ACI Emerging Member, and ACI Ambassador Speaker, and awarded the Portland Cement Association Fellowship, UM SEEDS You Choose Leadership Award, TRB Concrete Materials Section Best Paper Award, Slag Cement Association Research Project of the Year, and the RILEM prestigious Gustavo Colonnetti Medal.