Some contributions to the examination of composites from power plant wastes

Prvoslav Trifunovic,Rade Tokalic,Slobodanka Marinkovic

doi:10.5937/podrad1527041t

Abstract

This paper describes an investigation into the possibilities of the use of all three types of solid power plant wastes: fly ash (FA), flue gas desulphurization gypsum (FGD gypsum) and bottom ash (BA) as components of composites for road construction. Two mixtures were made: 1. power plant wastes - Portland cement (PC) and 2. power plant wastes - sand (S) - Portland cement (PC). The mass ratio of components in these mixtures was: 1. FA - FGD gypsum - BA - PC = 2 : 1.5 : 5 : 1.5 and 2. FA- FGD gypsum-BA - S - PC= 2 : 1.5 : 4 : 1 : 1.5. For both mixtures, the compressive strength, the mineralogical composition, the water absorption and the resistance to freeze-thaw treatment were determined 7 and 28 days after preparation of samples (mixing with water). The obtained results showed that both mixtures could have potential to be used for sub-base layers in road construction and the second mixture (with natural aggregate-sand) has advantage over the first mixture in terms of compressive strength, mineralogical composition, and resistance to freeze-thaw treatment.

Highlights

The thermal power plants produce three types of solid wastes
The aim of this work was to broaden the knowledge concerning the applicability of power plant wastes as components in cement based composites for road construction fly ash (FA) and bottom ash (BA), applied in this work, originated from Serbian power plant "Nikola Tesla" and FGD gypsum from Bohemian Power Plant - Hvaletice
Two kinds of the mixtures were made: the first was composed of power plant wastes (FA, FGD gypsum, BA), Portland cement (PC) and water (W) and the second contained sand (S) in addition to the mentioned components in the first mixture

Summary

Introduction

The thermal power plants produce three types of solid wastes (fly ash - FA, flue gas desulphurization gypsum - FGD gypsum and bottom ash - BA). The disposal of these wastes is an economic and an ecological problem (pollution of air, waters and soil). FA with low CaO content (the class F according to ASTM 618) may exhibit pozzolanic properties and could be applied as a substitute for Portland cement (PC) in concrete (Manz, 1999; Benavidez et al 2003; McCarthy and Dhir, 1999; Freidin and Motzafi-Haller, 1999; Asokan et al 2005). BA is a more or less inert material, i.e., bottom ash usually does not exhibit pozzolanic properties, but it could be a potential aggregate in concrete as a replacement for natural sand (its particles are coarse, sized between sand and gravel, fused and with a glassy texture) (Benavidez et al 2003; Cheriaf et al 1999; Bai and Basheer, 2003)

Objectives

Methods

Results

Conclusion