Journal Published Online: 28 February 2019
Volume 8, Issue 2

Behavior of Specialty Binders Mixed with Seawater

CODEN: ACEMF9

Abstract

In recent years, worldwide research has been facing the challenge of finding solutions able to decrease the environmental impact of cement and concrete production. Many strategies could be adopted in order to reach this goal, such as reducing the clinker factor in cement or producing alternative clinkers to portland clinker, in addition to the adoption of efficient water recycling processes in concrete production, thus reducing the consumption of natural resources. An interesting approach to implementing the different strategies is to develop concretes combining the use of cement and seawater, permitting a significant saving in fresh water consumption and offering an important benefit to countries that are facing a water shortage. Thanks to the recent technological improvement in the composite material sector, corrosion-free reinforcements have been successfully developed, thus proposing an alternative to steel rebars in concrete, especially in exposure conditions that are critical because of the presence of chloride, or even in combination with seawater. The use of a specialty binder based on an intrinsically low pH and a high sulfate resistance can be beneficial for the stability of the concrete and of the embedded glass-fiber–reinforced polymer rebars. This article compares the mineralogical and mechanical behavior of pastes and mortars containing (1) limestone portland cement, (2) sulfoaluminate cement and (3) a blend of the two, when mixed with seawater. Compressive strength and drying shrinkage tests were performed, and the results were interpreted on the basis of the microstructural data obtained through X-Ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC). The results suggest that the phase assemblage of the systems and, in particular, the equilibria among the different Al2O3-Fe2O3-monovalent anion (AFm)/Al2O3-Fe2O3-trivalent anion (AFt) minerals play a key role in the strength development mechanism.

Author Information

Bertola, Federica
Department of Research and Development, Buzzi Unicem, Casale Monferrato, Italy
Gastaldi, Daniela
Department of Research and Development, Buzzi Unicem, Casale Monferrato, Italy
Canonico, Fulvio
Department of Research and Development, Buzzi Unicem, Casale Monferrato, Italy
Pages: 14
Price: $25.00
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Stock #: ACEM20180107
ISSN: 2379-1357
DOI: 10.1520/ACEM20180107