ABOUT THE INTERNATIONAL CONCRETE ABSTRACTS PORTAL

  • The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.

International Concrete Abstracts Portal

Showing 1-5 of 51 Abstracts search results

Document: 

SP320

Date: 

September 1, 2017

Author(s):

Arezki Tagnit-Hamou

Publication:

Symposium Papers

Volume:

320

Abstract:

The purpose of this international conference is 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, which are receiving increasing attention from the research community. The conference was held in Montréal, 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.


Document: 

SP-320_44

Date: 

August 1, 2017

Author(s):

Daniela Hesselbarth, Thomas Moser, and Juerg Sturzenegger

Publication:

Symposium Papers

Volume:

320

Abstract:

Cement production is an energy-intensive process, responsible for a significant amount of the world’s carbon dioxide emissions. Over the last years, geopolymers have been often promoted as an ecologically friendly alternative with low CO2 footprint. The presented work proposes curing of geopolymers at ambient temperature for application as construction materials. Different aluminosilicates like fly ash, metakaolin, slag and combinations thereof are evaluated as binders. Furthermore, the influence of alkali silicate activator (water glass), with respect to type and molar ratio, on the resulting geopolymer properties is investigated. This paper discusses characteristics of ambient temperature cured geopolymers, such as workability, mechanical, and physical properties. The achieved mechanical properties represent medium performance as well as high performance.


Document: 

SP-320_29

Date: 

August 1, 2017

Author(s):

William Wilson, Luca Sorelli, and Arezki Tagnit-Hamou

Publication:

Symposium Papers

Volume:

320

Abstract:

A better understanding of the microstructural features of cement matrices incorporating supplementary cementitious materials (SCMs) represents key knowledge for engineering more sustainable concrete infrastructures. By fostering the coupling of nanoindentation techniques with quantitative energy-dispersive Xray spectroscopy (NI-QEDS), this work aims at disclosing the effects of substituting Portland cement by 30% fly ash or 50% slag on hydrous and anhydrous phases. Notably, after one year of hydration, measurements attributed to calcium-(aluminum)-silicate-hydrates, C-(A)-S-H, showed average Ca/(Si+Al) ratios < 1.5 for the pastes with SCMs, compared to Ca/(Si+Al) 1.9 for a Portland-cement-only paste. Interestingly, an intermix of C-(A)-S-H and hydrotalcite-like phases was also found in the slag-containing system. Nevertheless, similar micro-mechanical properties were found for these different C-(A)-S-H (modulus M 26–29 GPa [3770–4205 ksi] and hardness H 0.8–0.9 GPa [115–130 ksi]), which indicate that C-A-S-H formed by fly ash or slag reaction may replace Portland-cement C-S-H with equivalent mechanical properties at the micrometer scale.


Document: 

SP-320_48

Date: 

August 1, 2017

Author(s):

Reda Jaafri, Abdelilah Aboulayt, Syed-Yasir Alam, Emmanuel Roziere, and Ahmed Loukili

Publication:

Symposium Papers

Volume:

320

Abstract:

Slabs are subjected to many important drying effects due to their large exchange surface area, particularly plastic and drying shrinkage. The use of suitable mineral additions with shrinkage reducing properties is necessary to improve cement-based materials behavior. The aim of the experimental work carried out is to investigate the influence of natural hydraulic lime (NHL) and aerial lime (AL) on the properties of cement mortars at fresh and hardened state. A reference mortar was designed with a water-to-cement ratio of 0.6. At a constant paste volume, cement was replaced with increasing mass proportions of 12.5%, 25% and 50% of NHL. The approach used shows that the substitution of cement by either type of lime reduces plastic and drying shrinkage, but negatively affected rheological behavior and compressive strength. The findings of this paper highlight the benefits of lime/cement substitution on the volume changes in cement mixtures at early age and long-term.


Document: 

SP-320_24

Date: 

August 1, 2017

Author(s):

Tahar Tioua, Abdelouahed Kriker, Abderrahim Bali, Gonzalo Barluenga and Mourad Behim

Publication:

Symposium Papers

Volume:

320

Abstract:

An experimental study was carried out to assess the effect of low volumetric fractions of short natural date palm fibers (DPF) compared to polypropylene fibers (PPF) on self-compacting concrete (SCC) flowability and hardened properties. Fibers can reduce concrete shrinkage cracking at early age and enhance other hardened concrete properties, although reducing other characteristics as SCC flowability. The use of DPF instead of PPF has two advantages: their use in construction provides new outlets for low cost agricultural resources, and the valorization of natural fibers allows to reduce environmental impacts, since these are renewable raw materials and need little energy to be produced. Slump flow, V-funnel and L box tests were used to assess flowability. Mechanical and physical properties, including compressive and flexural strength, were also measured. It was found that DPF can successfully replace PPF although DPF reduced SCC flowability slightly more than PPF, but produced similar effects in SCC hardened properties.


12345...>>

Results Per Page 




Please enter this 5 digit unlock code on the web page.