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International Concrete Abstracts Portal

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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_49

Date: 

April 22, 2021

Author(s):

R.Douglas Hooton

Publication:

Symposium Papers

Volume:

349

Abstract:

Approximately 90% of the carbon footprint from concrete production is from portland cement (assuming portland cement is used as the sole cementitious binder). Therefore to reduce its carbon footprint, the amount of Portland cement clinker needs to be reduced. There are different ways of doing this, including optimization of combined aggregate gradations, use of water reducing admixtures, use of portland-limestone cements (PLC), and use of supplementary cementitious materials (SCMs). All of these measures can be taken simultaneously, but there is also concern that extreme measures (such as high SCM replacement levels) will reduce the robustness of concrete to abuse during construction, resulting in lower durability. Durability is important to obtain long service lives of concrete structures, and has a large impact on their carbon footprint.

This paper includes discussion of how each these measures if used prudently, can achieve significant reductions in carbon footprint while simultaneously improving durability in aggressive exposure conditions.


Document: 

SP-349_17

Date: 

April 22, 2021

Author(s):

Hugo Valido Deda, Leandro Francisco Moretti Sanchez, Mayra Tagliaferri de Grazia

Publication:

Symposium Papers

Volume:

349

Abstract:

Although the 28-day concrete compressive strength is often used as a quality control indicator, early-age mechanical properties are becoming more critical to optimize construction scheduling. Numerous advanced techniques have been proposed in this regard and among those, electrical resistivity (ER), a non-destructive and inexpensive technique able to characterize the microstructure development of cementitious materials has been showing promising results. Yet, recent literature data have evidenced that ER might be significantly influenced by a variety of parameters, such as the binder type/amount and aggregates nature used in the mix. These factors can hinder the practical benchmark of concrete mixtures proportioned with distinct raw materials. Thus, six concrete mixtures incorporating two types of aggregates (granite and limestone) and two ground granulated blast furnace slag cement replacements (e.g. 0%, 35%, and 70%) were manufactured for this research. Moreover, three distinct ER techniques (e.g. Bulk, Surface, and Internal) and compressive strength tests were performed at different concrete ages. Results show that the binder replacement may significantly affect ER results over time, whereas the aggregate type presented a less significant impact.


Document: 

SP-349_02

Date: 

April 22, 2021

Author(s):

Alexander German, Frank Winnefeld, Pietro Lura

Publication:

Symposium Papers

Volume:

349

Abstract:

MgO/hydromagnesite (Mg5(CO3)4(OH)2·4H2O, abbreviated as HY) blends are cementitious materials, which set and harden when mixed with water. These blends reach acceptable strengths and therefore can potentially be used as binders in mortars and concrete. In case MgO is derived from carbonation of magnesium silicates and subsequent calcination, MgO/HY blends offer the possibility to be used as alternative binders with reduced carbon footprint compared to normal portland cement-based products.

This study focuses on the characterization of hydration products and mechanical properties of MgO/HY blends. Hydration of solely MgO leads to formation of brucite (Mg(OH)2) without any strength-building properties. In contrast, by blending MgO with hydromagnesite, it is possible to produce mortar samples with a strength of up to 11.0 ± 0.4 MPa (1595 ± 58 psi) after 28 d. Moreover, blending with hydromagnesite accelerates early hydration of MgO. XRD and TGA studies of hydrated blends revealed the presence of brucite and of a poorly crystalline, unidentified hydrate phase. The latter might play an important role in strength development.


Document: 

SP-349_13

Date: 

April 22, 2021

Author(s):

Gonzalo A. Lozano Rengifo, Mayra T. de Grazia, Leandro F. M. Sanchez, and Edward G. Sherwood

Publication:

Symposium Papers

Volume:

349

Abstract:

Reducing Normal Portland Cement (NPC) has been a major concern of concrete industry and research community over the last 2-3 decades. As much as 8% of the global CO2 emissions stem from clinker production. Hence, a wide number of research projects have been focusing on reducing NPC in cementitious materials using numerous strategies such as the use of supplementary cementing materials (SMC’s), limestone fillers (LF) and/or advanced mixproportioning techniques. Yet, the impact of these procedures on the overall behaviour of materials with low NPC content, especially in the fresh state and long-term durability, is still not fully understood. This work aims to understand the influence of the distance between the fine particles, the so-called Inter-Particle Separation (IPS), on the fresh state behaviour of cement-base pastes designed through the use of Particle Packing Models and incorporating LF. Evaluations on the fresh (i.e. rheological behaviour and setting time) and hardened states (compressive strength) were conducted in all mixtures. Results show that IPS directly correlates with the viscosity of cementbase pastes for all shear rates appraised. Moreover, the use of LF increases the hydration rate of NPC pastes. Finally, it is clear that the water-to-cement ratio keeps being the main factor controlling the compressive strength of cement pastes with reduced NPC content and high levels of LF replacement.


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