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International Concrete Abstracts Portal

Showing 1-5 of 799 Abstracts search results

Document: 

SP349

Date: 

April 28, 2021

Publication:

Symposium Papers

Volume:

349

Abstract:

Sponsors: American Concrete Institute, RILEM, Université de Sherbrooke, CRIB, Université Toulouse III, Lmdc Toulouse, Kruger Biomaterials, Euclid Chemical, Prodexim International inc., BASF Master Builders, ACAA Editor: Arezki Tagnit-Hamou In July 1983, the Canada Centre for Mineral and Energy Technology (CANMET) of Natural Resources Canada, in association with the American Concrete Institute (ACI) and the U.S. Army Corps of Engineers, sponsored a five-day international conference at 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 taken place 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 renewed interest in alternative and sustainable binders and supplementary cementitious materials, a new series was launched by Sherbrooke University (UdeS); ACI; and the International Union of Laboratories and Experts in Construction materials, Systems, and Structures (RILEM). They, 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 in Montréal, QB, Canada, from October 2 to 4, 2017. The conference proceedings, containing 50 refereed 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 held online from June 7 to 10, 2021. The conference proceedings, containing 53 peer reviewed papers from more than 14 countries, were published as ACI SP-349. 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 was to highlight advances in the field of alternative and sustainable binders and supplementary cementitious materials, which are receiving increasing attention from the research community. To all those whose submissions could not be included in the conference proceedings, the Institute and the Conference Organizing Committee extend their appreciation for their interest and hard work. Thanks are extended to the members of the international scientific committee to review the papers. Without their dedicated effort, the proceedings could not have been published for distribution at the conference. The cooperation of the authors in accepting reviewers’ suggestions and revising their manuscripts accordingly is greatly appreciated. The assistance of Chantal Brien at the Université de Sherbrooke is gratefully acknowledged for the administrative work associated with the conference and for processing the manuscripts, both for the ACI proceedings and the supplementary volume. Arezki Tagnit Hamou, Editor Chairman, eleventh ACI/RILEM International Conference on Cementitious Materials and Alternative Binders for Sustainable Concrete (ICCM2021). Sherbrooke, Canada 2021


Document: 

SP-349_45

Date: 

April 22, 2021

Author(s):

Bakhta Boukhatem, Ablam Zidol and Arezki Tagnit-Hamou

Publication:

Symposium Papers

Volume:

349

Abstract:

This study presents an accurate corrosion prediction through an intelligent approach based on deep learning. The deep learning is used to predict the time-to-corrosion induced cover cracking in reinforced concrete elements exposed to chlorides ions. The key parameters taken into consideration include thickness, quality and condition of the concrete cover. The prediction performance of the deep learning model is compared against traditional machine learning approaches using neural network and genetic algorithms. Results show that the proposed approach provides better prediction with higher generalization ability. The efficiency of the method is validated by an accelerated corrosion test conducted on 91 and 182-day moist cured reinforced fly ash concrete samples with different water-to-binder ratios. The results are in agreement with the model predictions. They also show that using the proposed model for numerical investigations is very promising, particularly in extracting the effect of fly ash on reducing the extent of corrosion. Such an intelligent prediction will serve as an important input in order to assist in service life prediction of corroding reinforced concrete structures as well as repair evaluation.


Document: 

SP-349_22

Date: 

April 22, 2021

Author(s):

Malene T. Pedersen, Barbara Lothenbach, and Frank Winnefeld

Publication:

Symposium Papers

Volume:

349

Abstract:

In this work, a non-ferrous metallurgical slag has been characterized and its reactivity has been assessed and compared to current SCMs. Additionally, the hydration of a blend of portland cement with 30 wt. % replacement by slag was investigated for hydration kinetics, hydrate phase assemblage and mechanical strength up to 91 days using isothermal calorimetry, XRD and compression tests. The reactivity tests revealed pozzolanic reactivity of the slag and a dissolution behavior comparable to fly ash. The hydrate phase assemblage of the PC-slag blend showed a difference in the AFm phases forming compared to the portland cement reference, which was suggested to be due to the incorporation of Fe. The compressive strength after 28 days of hydration was correlated with the cumulative heat after 7 days of hydration and then compared to current SCMs. Also these results show that the non-ferrous metallurgical slag compares to siliceous fly ash. Hence, this work shows that Fe-rich non-ferrous slags are suitable candidates as SCMs in portland cement.


Document: 

SP-349_35

Date: 

April 22, 2021

Author(s):

Alexandre Rodrigue, Josée Duchesne, Benoit Fournier and Benoit Bissonnette

Publication:

Symposium Papers

Volume:

349

Abstract:

Alkali-activated slag/fly ash concretes activated with combined sodium silicate and sodium hydroxide show good mechanical and durability properties in general. When tested in terms of resistance to freezing and thawing cycling in watersaturated conditions, the concretes tested in this study show final values of relative dynamic modulus averaging 100% after 300 cycles. However, all tested concretes showed poor performance towards freezing and thawing in presence of de-icing salts with only one tested mixture showing a final average scaling value below 0.5 kg/m². Early-age microcracking is observed on all tested concretes and is correlated to high values of autogenous shrinkage in equivalent paste mixtures. Increasing the fly ash content reduces both the observed autogenous shrinkage and early-age cracking. Low drying shrinkage values ranging from 470 to 530 μm/m after 448 days of measurements at 50% RH and 23°C are noted. The use of fly ash in these alkali-activated concretes reduces the expansion levels of concrete specimens incorporating alkali-silica reactive aggregates. With increasing fly ash contents (20, 30 and 40% replacement), decreasing expansions are observed for any given reactive aggregate. In general, the durability properties measured in this study were improved by partially substituting slag with fly ash as binder material.


Document: 

SP-349_40

Date: 

April 22, 2021

Author(s):

Victor Poussardin, Michael Paris, Dimitri Deneele, and Arezki Tagnit-Hamou

Publication:

Symposium Papers

Volume:

349

Abstract:

Although normal portland cement is made from natural and recyclable materials its manufacture causes significant pollution, especially because of clinkerization which leads to important CO2 releases into the atmosphere. The use of supplementary cementitious materials (SCMs) to partially replace clinker in normal portland cement and reduce its environmental cost is now well known (e.g., fly ash, metakaolin, glass powder or blast-furnace slag). This study investigates the potential for calcination and reactivity of a carbonate sample containing phyllosilicates. Samples were calcined at different temperatures and investigated using X-ray diffraction (XRD) with Solid State Nuclear Magnetic Resonance (NMR). The results show that the calcination of the sample leads to a dehydroxlation phenomenon of the clay fraction resulting in a change in the coordination of the aluminium atoms. Furthermore, the reaction between the Dolomite and the Palygorskite present in the sample leads to the formation of poorly-crysallized Belite during calcination. Hydration tests on the red-clay sample have demonstrated the hydraulic reactivity of the Belite and the pozzolanic reactivity of the calcined Palygorskite that lead to the formation of hydrates phases (C-S-H ; C-(A)-S-H). The multi-technique analysis applied in this study allows to highlight a direct correlation between the structural modification induced by calcination and the reactivity of the calcined sample.


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