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.

DOI:

10.14359/51701166


Document: 

SP-320_42

Date: 

August 1, 2017

Author(s):

Théau Conte and Mohend Chaouche

Publication:

Symposium Papers

Volume:

320

Abstract:

Cement pastes exhibit virtually all the rheological features of complex fluids. Thus, several rheological methods and setups have been used in the literature to characterize these materials. In the present investigation Large Amplitude Oscillatory Shear (LAOS) is for the first time exploited for cement pastes. LAOS can be used to characterize all the rheological properties within a single procedure. This technique is tested in the case of three different cement mixes: a Portland cement paste, nanoclay blended cement paste and a cement paste containing a hydro-soluble polymer. These mixes were selected in order to get rheological properties that are different both quantitatively and qualitatively. Indeed, addition of a low amount of nanoclay increased significantly the yield stress and the shear-thinning/thixotropic aspects of the cement paste, whereas addition of cellulose ether led to the decrease of yield stress and thixotropy. These non-linear rheological properties are discussed within the framework of LAOS.

DOI:

10.14359/51701080


Document: 

SP-320_43

Date: 

August 1, 2017

Author(s):

Mohammad A. Aqel, and Daman K. Panesar

Publication:

Symposium Papers

Volume:

320

Abstract:

The focus of this paper is to evaluate the effect of replacing 15% (by weight) of the cement by limestone filler on the concrete expansion due to delayed ettringite formation. The freeze-thaw testing and microstructural analysis were conducted to further assess the damage caused by the expansion due to delayed ettringite formation. This study also evaluates the interplay between cement type (Type GU and Type HS), limestone filler content (0 and 15% by weight), and steam curing temperature (55°C [131°F] and 82°C [180°F]). The results showed that replacing 15% of the cement reduced the expansion of concrete due to delayed ettringite formation. However, this reduction in the concrete expansion was insignificant compared to the reduction in concrete expansion when the steam curing temperature was reduced from 82°C [180°F] to 55°C [131°F] or when cement with low sulfate and alkali contents (i.e., HS cement) was used instead of GU cement.

DOI:

10.14359/51701081


Document: 

SP-320_50

Date: 

August 1, 2017

Author(s):

Kamilia Abahri, Chady El Hachem, Fares Bennai, Ngoc Toan, and Rafik Belarbi

Publication:

Symposium Papers

Volume:

320

Abstract:

This study presents experimental and 3D correlation results of the microstructural hygrothermal behavior of hemp concrete. The experimental procedure was performed using non-destructive method’s X-ray tomography and digital microscopy. Hemp concrete specimens were scanned and examined at different relative humidity levels through a specifically developed processing protocol. The material response to temperature in the range of 25°C to 110°C where also analyzed via the 3D topology post-processing. After that, 3D correlation is performed on the reconstructed volumes, with fined resolution of 17μm/voxel, in order to quantify the various displacements due to the hygric load. The imaging data and the 3D correlation results allowed having access to the displacement field caused by the relative humidity and temperature solicitations on real structure of hemp concrete. These results provide reliable data on the microstructural evolution when studying aging or the material durability.

DOI:

10.14359/51701088


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.

DOI:

10.14359/51701086


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