International Concrete Abstracts Portal

ACI PRC-214.4-21 and ACI CODE-562-21 provide methods for converting concrete core strength test results into equivalent specified concrete strengths. The research discussed in this paper investigates the applicability of these methods as well as their limitations.

Maya Cottongim received the ACI Foundation’s 2020-2021 Baker Student Fellowship and has been greatly involved with ACI since. Her contributions to the ACI Arizona Chapter exemplify the profound impact that dedicated individuals can have on their professional communities.

ASTM C94/C94M, “Standard Specification for Ready-Mixed Concrete,” used to include a requirement for completing discharge of concrete from a concrete truck within 90 minutes from batching. Starting with the 2021 edition of the standard, this rule was replaced with the alternative for a time limit to be established between the purchaser and the concrete producer.

In July of 1983, the Canada Centre for Mineral and Energy Technology of Natural Resources Canada (CANMET), in association with the American Concrete Institute (ACI) and the U.S. Army Corps of Engineers, sponsored a 5-day international conference in Montebello, Quebec, Canada, on the use of fly ash, silica fume, slag, and other mineral by-products in concrete. The conference brought together representatives from industry, academia, and government agencies to present the latest information on these materials and to explore new areas of needed research. Since then, eight other such conferences have been held around the world (Madrid, Trondheim, Istanbul, Milwaukee, Bangkok, Madras, Las Vegas, and Warsaw). The 2007 Warsaw Conference was the last in this series. In 2017, due to the renewed interest in alternative and sustainable binders and supplementary cementitious materials, a new series was launched by Sherbrooke University (Professor Arezki Tagnit-Hamou), American Concrete Institute (ACI), and the International Union of Laboratories and Experts in Construction Materials, Systems and Structures (RILEM)—in association with a number of other organizations in Canada, the United States, and the Caribbean—sponsored the 10th ACI/RILEM International Conference on Cementitious Materials and Alternative Binders for Sustainable Concrete (ICCM2017). The conference was held October 2-4, 2017, in Montréal, Canada. The conference proceedings, containing 50 reviewed papers from more than 33 countries, were published as ACI SP-320. In 2021, UdeS, ACI, and RILEM, in association with Université de Toulouse and a number of other organizations in Canada, the United States, and Europe, sponsored the 11th ACI/RILEM International Conference on Cementitious Materials and Alternative Binders for Sustainable Concrete (ICCM2021). The conference was scheduled to take place in Toulouse, but due to COVID, it was held online June 7-10, 2021. The conference proceedings, containing 53 reviewed papers from more than 21 countries, were published as ACI SP-349. In 2024, the conference was finally held in-person in Toulouse from June 23 to 26, 2024, with the support of UdeS, ACI, and RILEM in association with Université de Toulouse (Martin Cyr) and a number of other organizations in Canada, the United States, and Europe. The purpose of this international conference was to present the latest scientific and technical information in the field of supplementary cementitious materials and novel binders for use in concrete. The new aspect of this conference is to highlight advances in the field of alternative and sustainable binders and supplementary cementitious materials for the transition to low carbon concrete. The conference proceedings, containing 78 reviewed papers from more than 25 countries, have been published as ACI SP-362. Thanks are extended to the members of the International Scientific Committee who reviewed the papers. The cooperation of the authors in accepting the reviewers’ suggestions and revising their manuscripts accordingly is greatly appreciated. The involvement of the steering committee and the organizing committee is gratefully acknowledged. Special thanks go to Chantal Brien (Université de Sherbrooke) for the administrative work associated with the conference and for processing the manuscripts for both the ACI proceedings and the supplementary volume. Arezki Tagnit Hamou, Editor Chairman, 12th ACI/RILEM International Conference on Cementitious Materials and Alternative Binders for Sustainable Concrete (ICCM2024). Sherbrooke, Canada, 2024

The effects of palygorskite-containing clays in cementitious materials are strongly dependent on the calcination temperature, which affects both reactivity and water demand. This study focuses on a palygorskite containing clay calcined at temperatures between 600 and 900°C with the aim of establishing a relationship between the water demand of cementitious mixtures containing 20% of the calcined clay (measured with the mini-spread flow test) and the Specific Surface Area (SSA) or the porosity of the clay itself (measured by nitrogen physiosorption). Results showed a decrease of SSA with increasing temperature (especially at 800 and 900°C), as well as a linear relationship between the water demand and SSA for cementitious mixtures containing the clay calcined between 600°C and 900°C. Imaging of clays showed structural modifications with calcination: the porosity closes, and the needle-like shape of the particles disappears. Since the reactivity of the clay is the highest for a certain temperature range, it is then necessary to find a calcination temperature that both minimizes the water demand and maximizes the reactivity.