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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_14

Date: 

April 22, 2021

Author(s):

Harald Justnes, Klaartje De Weerdt and Tone A. Østnor

Publication:

Symposium Papers

Volume:

349

Abstract:

Portland cements were made by mixing 4 different clinkers with 2 gypsum levels and 0-5% limestone powder. The compressive strength after 28 days of curing varied from 40 (5802) to 70 MPa (9718 psi) for mortar with equal w/c. Some of the clinkers were replaced with 4 different fly ashes and the response on strength differed. To explain the relatively large differences in strength evolution, the clinker and fly ash composition was investigated by SEM-BSE/EDS, the oxide compositions were determined by XRF and differences in clinker mineralogy determined by XRD Rietveld analysis. The microstructure of hydrated cement pastes of clinker/fly ash was investigated by SEM/EDS.

The highest strength was achieved with the white clinker containing no C4AF, produced using CaSO4/CaF2 flux, and therefore contained a higher total calcium sulphate content. The white cement also seemed to contain two calcium aluminate phases with potentially some fluoride in one of them, one probably glassy as Rietveld analysis underestimated C3A. The C4AF content of the other clinkers have low reactivity within the 28 days explaining some of the difference. One “fly ash” was actually a fluidized bed ash with higher calcium and sulphate content and different morphology explaining the different behavior from the other fly ashes.


Document: 

SP-349_46

Date: 

April 22, 2021

Author(s):

Shizhe Zhang, Qingge Feng, Dongbo Wang, and Guang Ye

Publication:

Symposium Papers

Volume:

349

Abstract:

Strain-hardening geopolymer composite (SHGC) based on industrial wastes and by-products has emerged as a feasible alternative to strain-hardening cementitious composite (SHCC). Lately, a novel slag/fly ash-based SHGC with promising strain-hardening tensile performance and multiple cracking behavior has been successfully developed. However, its environmental impact with regards to its global warming potential and energy consumption remain to be evaluated.

This paper presents an evaluation and comparative study of the environmental impact factors of a newly developed slag/fly ash-based SHGC and three different types of conventional SHCC materials. The CO2 equivalent global warming potential (GWP) and the embodied energy (EE) were calculated under a life cycle assessment scheme based on the product stage. SHGC has significant advantages in terms of the global warming potential (GWP) while maintaining comparable or lower embodied energy (EE) when compared with greener version of SHCC materials and typical SHCC material (ECC M45), respectively. It could be concluded that the newly developed slag/fly ash-based SHGC demonstrates a very promising LCA record while possessing excellent technical performance. Consequently, SHGC could serve as a promising alternative for SHCC materials with considerably lower environmental impact.


Document: 

SP-349_50

Date: 

April 22, 2021

Author(s):

Chathurani Chandrasiri, Zihui Li and Sulapha Peethamparan

Publication:

Symposium Papers

Volume:

349

Abstract:

The potential of using naturally occurring kaolinite clay as a low embodied energy fine material additive to enhance the performance of alkali-activated slag and fly ash binders are evaluated. The behavior of kaolinite clay (KC) containing systems was compared to that of the most popular nanoparticle, nao-silica (NS), incorporated binders. Kaolinite clay was added at 2 and 6 % by mass of the slag and fly ash to modify the early age hydration kinetics, strength development, and acid leaching resistance of alkali-activated binders. Sodium silicate solutions with a 1.5 silica modulus (SiO2 /Na2O) and a 2.5 or 5% Na2O% (by mass of the binder) respectively for slag and fly ash mixtures were used. Similarly to the nano-silica containing systems, higher dosages of kaolinite clay significantly improved the compressive strength of alkali-activated binder systems. Kaolinite clay fine particles accelerated the early age hydration kinetics and modified the microstructure developments. The clay incorporated alkali-activated binders outperformed that of nano-silica incorporated binders in the acidic environment.


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.


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