International Concrete Abstracts Portal

Reefs provide many ecosystem services, such as fish habitats, coastal buffers that help break wave energy, and homes for filter-feeding oysters that improve water quality. Over the last few decades, environmentalists around the world have been incorporating precast concrete into the construction of purpose-built reefs and living shorelines, restoring habitats for marine life and protecting fragile coastlines from storm devastation. The Reef Ball Foundation in Athens, GA, USA, is using precast concrete to revive coastal ecosystems by mimicking natural reefs. This article highlights the foundation’s strategies and projects for worldwide reef restoration.

The first international symposium on “Advances in Concrete Technology” was sponsored jointly by Canada Centre for Mineral and Energy Technology (CANMET), the American Concrete Institute (ACI), and several other international organizations in Athens, Greece, in May 1992. Dr. Mohan Malholtra served as the chairman of the symposium. In June 1995, CANMET, in association with ACI and various professional organizations from the United States and Canada, sponsored the Second CANMET/ACI Symposium on Advances in Concrete Technology in Las Vegas, NV, USA. This event focused on high-performance normalweight and lightweight concretes, with the proceedings formally published as ACI SP-154. The Third CANMET/ACI Symposium on Advances in Concrete Technology was held in Auckland, New Zealand, in August 1997, sponsored by CANMET, ACI, and partner organizations from Canada and New Zealand. The symposium brought together industry, university, and government representatives to explore new areas of research, resulting in the publication of 33 refereed papers from 15 countries as ACI SP-171. In June 1998, the Fourth CANMET/ACI Conference on Advances in Concrete Technology took place in Tokushima, Japan, sponsored by CANMET, ACI, the Japan Concrete Institute (JCI), and several organizations from Japan and Canada. From more than 80 submissions across 20 countries, 61 refereed papers were published as ACI SP-179, while more than 30 additional technical contributions were presented. The Fifth CANMET/ACI Conference on Advances in Concrete Technology was held in Singapore in July and August 2001, under the sponsorship of CANMET, ACI, and multiple Singaporean organizations. This milestone event saw over 100 papers from 25 countries, leading to the publication of 46 refereed papers as ACI SP-200, and more than 25 additional papers were presented. In June 2003, the Sixth CANMET/ACI Conference on Advances in Concrete Technology was held in Bucharest, Romania, with sponsorship by CANMET, ACI, and several Romanian organizations. During this event, more than 40 technical papers were distributed to participants as received, though no formal ACI Special Publication was issued for this symposium. The Seventh CANMET/ACI Conference on Advances in Concrete Technology was held in May 2004 in Las Vegas, USA, sponsored by CANMET, ACI, and several U.S. organizations. The technical program resulted in 17 refereed papers from more than 10 countries published as ACI SP-222. In May 2006, CANMET, ACI, and organizations from Canada and the United States sponsored the Eighth CANMET/ACI Conference on Advances in Concrete Technology in Montreal, QC, Canada. The proceedings, consisting of 17 refereed papers, were published as ACI SP-235, supplemented by more than 30 additional technical papers distributed at the venue. The Ninth CANMET/ACI Conference on Advances in Concrete Technology was conducted in Warsaw, Poland, in May 2007, under the sponsorship of CANMET, ACI, and partners from Canada, Europe, and the United States. The final proceedings included 10 refereed papers published as ACI SP-243 along with more than 20 supplementary papers. Sponsored by ACI in association with several organizations from Canada, Europe, and the United States, the Tenth ACI Conference on Advances in Concrete Technology took place in Seville, Spain, in October 2009. This event produced 20 refereed papers published as ACI SP-261, while more than 20 additional papers were released in a supplementary volume. In May 2010, the Committee for the Organization of International Conferences (COIC) (formerly CANMET/ACI Conferences) and the Chinese Ceramics Society (CCS) sponsored the Eleventh International Conference on Advances in Concrete Technology and Sustainability Issues in Jinan, China. This gathering featured the presentation of more than 40 papers, with the formal proceedings published by the CCS, Beijing, China. The Twelfth International Conference on Advances in Concrete Technology and Sustainability Issues was held in Prague, Czech Republic, in October 2012, sponsored by COIC and ACI with a new focus on sustainability issues. The resulting volume, ACI SP-288, featured more than 30 refereed papers, while an additional 40 papers were included in a supplementary volume. In July 2015, COIC and ACI sponsored the Thirteenth International Conference on Advances in Concrete Technology and Sustainability Issues in Ottawa, ON, Canada. This technical exchange yielded 28 refereed papers published as ACI SP-303, alongside with more than 40 other papers presented in a supplementary papers volume. The Fourteenth International Conference on Recent Advances in Concrete Technology and Sustainability Issues was sponsored by the CCS, the China Academy of Building Research (CABR), and COIC in Beijing, China, in October 2018. The technical output included 19 refereed papers published as ACI SP-330, with more than 52 additional papers featured in the supplementary volume. After a postponement due to the COVID-19 pandemic, the Fifteenth International Conference on Recent Advances in Concrete Technology and Sustainability Issues was sponsored by the ACI Italy Chapter and the University of Bergamo in Milan, Italy, in July 2022. This event focused on decarbonization and alternative binders, resulting in 44 refereed papers published as ACI SP-355, and approximately 20 papers were published in the supplementary volume. The Sixteenth International Conference on Recent Advances in Concrete Technology and Sustainability Issues is being held in Munich, Germany, from 8 – 10 July, 2026. This prestigious gathering is hosted by the Technical University of Munich (TUM) with the support of ACI. The conference continues its long-standing mission of advancing concrete science, with a sharp focus on the industry’s most pressing challenge: the transition of the cement industry towards decarbonization and the implementation of new technologies for long-term sustainability. 19 refereed papers for this conference are published herein as an ACI Special Publication, focusing on topics including: use of supplementary cementitious materials such as alkali-activated slag, calcined clay, red mud and other industrial wastes; pozzolanic reactivity of SCMs; long-term investigation on cement and cement additives; reduction on CO2 emission, etc. Additionally, more than 50 other papers will be presented at this event, most of them available in a Supplemental Papers Volume. The organizing committee expresses its profound gratitude to the authors, reviewers, and partner organizations whose dedication continues to drive the evolution of concrete technology toward a more sustainable future. Special thanks are also given to the American Concrete Institute for the publication of the proceedings. The Editor Prof. Dr. Johann Plank

In May 1978, the first 3-day conference on the use of superplasticizers in concrete was sponsored by the Canada Centre for Mineral and Energy Technology (CANMET) and the American Concrete Institute (ACI) in Ottawa, ON, Canada, with selected papers from the gathering published as ACI Special Publication SP-62. The Second International Conference on the Use of Superplasticizers in Concrete took place in 1981 in Ottawa, ON, Canada, again under the joint sponsorship of CANMET and ACI, with the resulting technical proceedings published as ACI SP-68. The Third International Conference hosted by CANMET and ACI was held in Ottawa, ON, Canada, in 1989 with the primary purpose of reviewing the technical progress achieved since the initial meetings in 1978 and 1981. This event marked a significant turning point for the series, as its scope was formally expanded beyond superplasticizers to include all other types of chemical admixtures. Furthermore, the conference successfully brought together representatives from the chemical admixtures, cement, and concrete industries to exchange information and delineate new areas of needed research. The comprehensive findings and technical contributions from this expanded dialogue were formally published by ACI as ACI SP-119. The Fourth International Conference was held in Montreal, QC, Canada, in October 1994, sponsored by CANMET in association with ACI and other organizations, with proceedings published as ACI SP-148. In October 1997, the Committee for the Organization of CANMET/ACI International Conference (ACI Council), in association with ACI and various Italian cement and concrete organizations, sponsored the Fifth conference in Rome, Italy, publishing the results as ACI SP-173. The Sixth conference was hosted in Nice, France, in October 2000, where the ACI Council and partners from Canada and France accepted 37 papers for publication in ACI SP-195. In October 2003, the ACI Council and organizations from Canada and Germany sponsored the Seventh conference in Berlin, Germany, featuring 39 papers published as ACI SP-217. The Eighth conference was held in Sorrento, Italy, in October 2006, sponsored by the ACI Council, with 36 papers accepted and published as ACI SP-239. In October 2009, the Committee for the Organization of International Conferences (COIC) sponsored the Ninth ACI International Conference in Seville, Spain, where 35 papers were accepted and published as ACI SP-262. The Tenth International Conference on Superplasticizers and Other Chemical Admixtures in Concrete took place in Prague, Czech Republic, in October 2012, sponsored by COIC, resulting in 33 accepted papers published as ACI SP-288. In July 2015, COIC and ACI sponsored the Eleventh International Conference on Superplasticizers and Other Chemical Admixtures in Concrete in Ottawa, ON, Canada, where more than 36 refereed papers were accepted and published as ACI SP-302. The Twelfth International Conference on Superplasticizers and Other Chemical Admixtures in Concrete was hosted in Beijing, China, in October 2018, sponsored by the Chinese Ceramic Society (CCS) and the China Academy of Building Research (CABR) in association with ACI, with 36 refereed papers published as ACI SP-329. Fifty-four additional papers were presented and were published in the Supplementary Papers volume. In July 2022, following a postponement due to the pandemic, the ACI Italy Chapter and the University of Bergamo sponsored the Thirteenth International Conference on Superplasticizers and Other Chemical Admixtures in Concrete in Milan, Italy, featuring 35 refereed papers published as ACI SP-354 and approximately 20 supplementary papers. The Fourteenth International Conference on Superplasticizers and Other Chemical Admixtures in Concrete is being held in Munich, Germany, from 6-8 July 2026. Hosted by the Technical University of Munich (TUM) with the support of ACI, this event continues a nearly 50-year tradition of fostering global dialogue on chemical innovations that enhance the performance and sustainability of concrete. Thirteen refereed papers for this conference are published herein as an ACI Special Publication, along with more than 60 presentations, most of them available in a Supplementary Papers volume, explore a wide range of topics, including superplasticizers, rheology-modifying agents, shrinkage-reducing agents, superabsorbent polymers, and self-healing admixtures. These studies examine the influence of admixtures on the properties of concrete in both fresh and hardened states, specifically addressing workability, slump retention, heat of hydration, strength, and durability. The organizing committee expresses its profound gratitude to the authors, reviewers, and partner organizations whose dedication continues to drive the evolution of concrete technology toward a more sustainable future. The support of the American Concrete Institute for the publication of the proceedings is gratefully acknowledged. The Editor Prof. Dr. Johann Plank

The effort of increasing the sustainability of concrete led to the development of a new class of admixtures specifically designed to reduce the carbon footprint of this material, hence called “Low Carbon Concrete Admixtures (LCCAs).” They act as hydration promoters for binders, increasing the degree of hydration and improving the compressive strength of the concrete. Consequently, the dosage of cement in a concrete can be reduced without affecting the mechanical properties of the resulting product. In the present work, a reference concrete mix was compared with concretes containing two different LCCAs, at different dosages of cement and water-to-cement ratios. Results confirmed the positive effect of LCCAs on strength development, water permeability, and water penetration, suggesting an improvement of the microstructure of concrete; this was confirmed by pore size distribution measurements. On the other hand, coulomb metric tests, like surface resistivity and rapid chloride penetration tests, did not confirm such effects. In an effort to further understand this apparent contradiction, rapid chloride penetration tests were repeated, and the chloride concentration of the cathodic half-cell was measured, revealing that many different ionic species, and not just Cl- ions, contribute to the total passing charge measured during the experiment.

Ultra-High-Performance Concrete (UHPC) provides excellent mechanical properties and durability but often relies on high cement content, raising sustainability concerns. To enhance environmental performance, supplementary cementitious materials (SCMs), such as recycled glass powder (RGP), are increasingly used as partial cement replacements. The efficiency of RGP as a reactive SCM is strongly influenced by its dispersion behavior, which depends on the chemical composition of the cement pore solution, including its pH and ionic concentration. In this study, pore solutions were extracted using vacuum filtration and pressure squeezing at varying water-to-cementitious ratios (w/cm) and pressures. Results showed that higher w/cm increased calcium concentrations and decreased alkali and sulfur content, whereas pressure squeezing yielded solutions that closely resembled those in UHPC. Sedimentation tests were performed in RGP suspensions prepared in deionized (DI) water, untreated pore solution, and polycarboxylate ether (PCE) based high-range water-reducing admixture (HRWRA) treated pore solution. Results indicated that untreated pore solutions caused rapid agglomeration and settling of RGP, whereas PCE addition stabilized suspensions and improved dispersion. The study advances understanding of RGP dispersion behavior and supports the more efficient utilization of SCMs, enabling reduced cement demand and more sustainable UHPC production.