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_09

Date: 

August 1, 2017

Author(s):

Gabriel Medina, José María Medina, Isabel F. Sáez del Bosque, Moisés Frías, María Isabel Sánchez de Rojas, César Medina

Publication:

Symposium Papers

Volume:

320

Abstract:

This study assesses the pozzolanic activity of two types of waste, one from biomass power plants and the other from the ornamental granite industry. These materials were first characterised chemically, physically, morphologically and mineralogically. Pozzolan reaction kinetics in the waste/portlandite system were then researched by analysing the crystalline compounds with instrumental techniques such as TGA and XRD. The findings showed that bioenergy plant waste exhibited pozzolanic activity comparable to the values reported for other agri-forest additions and greater than recorded for fly ash. Activity in the granite industry waste, in turn, was greater than in fly ash and lower than in silica fume and New Additions for the Design of Eco-Efficient Cements. Analysis of Pozzolanic Reaction Kinetics 9.3 sanitaryware waste. In light of these results, both types of waste would potentially be apt for use as additions in eco-friendly cements.

DOI:

10.14359/51701047


Document: 

SP-320_10

Date: 

August 1, 2017

Author(s):

Darshan Ballekere Kumarappa, Chathurani Chandrasiri and Sulapha Peethamparan

Publication:

Symposium Papers

Volume:

320

Abstract:

The drying shrinkage of alkali activated class C fly ash (FAC) is quantified in this study in accordance with ASTM C490. The effect of activator concentration is evaluated by varying silica modulus (SiO2/Na2O) and Na2O contents. An ordinary portland cement (OPC) mortar mixture is also evaluated for the comparison purposes. In general, drying shrinkage is significantly higher in FAC mortars than in OPC mortar. Higher amounts of both silica modulus and Na2O contents result in greater drying shrinkage. Hydration kinetics and porosity are also evaluated to describe the higher drying shrinkage exhibited by FAC mortars. FAC mortars with a larger drying shrinkage exhibited a lower mass loss, a reverse trend normally exhibited by OPC mortars. Internal curing and discrete polypropylene fiber addition are evaluated as potential shrinkage reducing methods. The results show that both methods are efficient in reducing the drying shrinkage in FAC mortars.

DOI:

10.14359/51701048


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