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Cement Hydration in the Presence of Municipal Solid Waste Incineration Fly Ash.


pdf icon Cement Hydration in the Presence of Municipal Solid Waste Incineration Fly Ash. (604 K)
Remond, S.; Bentz, D. P.; Pimienta, P.; Bournazel, J. P.

Material Science and Concrete Properties, 1st International Meeting. Proceedings. March 5-6, 1998, Toulouse, France, 63-70 pp, 1998.

Keywords:

cements; solid waste; fly ash; cement hydration

Abstract:

Incorporating wastes into concrete on an appropriately selective basis could help to solve some of the problems encountered in waste management. Some industrial by-products (fly ash and slag for example) have been used in the manufacture of cement and concrete for many years. However, before waste can be used on a large scale in concrete, the properties of the resulting concrete need to be studied in order to ensure that the new material is suitable for use in construction. The main aim of this research is to develop an approach for assessing the performance characteristics, environmental impact and durability of concretes containing wastes. In this paper we describe the study bearing on the environmental impact of these materials. This approach is based on a study of mortars containing an "experimental" waste, Municipal Solid Waste Incineration Fly Ash (MSWIFA). These wastes are very heterogeneous and contain large quantities of heavy metals and soluble salts which could give rise to problems when incorporated in concrete. The leaching of toxic materials from concretes containing wastes may present health and environmental risks. The quantities released over a period of time must therefore be determined in assessing the environmental impact of these concretes. To predict the quantities of toxic materials released in actual conditions of use over the long term, models of leaching from waste-containing concrete need to be developed. To achieve this, one must understand the influence of waste on cement hydration, the mechanisms by which pollutants pass into solution, and the evolution of the material microstructure during leaching. The objective of this study is to apply the CEMHYD3D model developed by Bentz and Garboczi to cement pastes containing MSWIFA in order to simulate the hydration of this material and the evolution of its microstructure during leaching. In this article, we describe the experimental study undertaken in order to determine the model input data.