Polymer repair products containing fly ash contaminated by denitrifiation process

摘要

The increase in the emphasis on the quality and long life of buildings and structures opens space for the development of new and progressive renovation materials. Current trends focus on using the by-products of thermal powerplants, fly ash (FA), produced by the combustion of pulverised coal, which is contaminated by the denitrification of the fumes. Because ammonia escapes from the concrete containing contaminated fly ash, further use of the fly ash in concrete or as a partial cement replacement is problematic. The most advantageous use of FA seems to be as a filler in polymerous materials. For this reason, this paper focuses on verifying new ways of using FA as a filler in polymer mortars and concretes, which are then used as structural and non-structural repair products and systems, according to the European Standard EN 1504-1. By studying four different types of FA, we found that FA, neither from high-temperature combustion nor fluid, contaminated by flue gas denitrification process does not deteriorate the properties of epoxy resin polymer repair products. Successful use of these by-products was proved by comparing the results of the physical and mechanical parameters of the polymer mortars containing contaminated FA with the reference polymer mortars containing only primary raw materials and polymer mortars with FA unaffected by the denitrification process. Computed tomography (CT) was used to analyse the microstructure and bond strength of the developed materials to underlying concrete surface; it was also confirmed that weather does not degrade the developed materials. Scanning electron microscopy (SEM) supported by dispersion spectral analysis proved that distribution of individual elements of filler in the developed repair products is even and FA particles were successfully incorporated in the enclosed structure of the polymer matrix. New materials are economically beneficial because a large amount of by-products are used in their composition (up to 60% by weight). They are capable of replacing a considerable proportion of the epoxy resin, which is the most expensive component of the material. In this way, a new possibility was developed for using contaminated FA as well as new polymer repair products and systems with excellent parameters. (C) 2020 Published by Elsevier Ltd.