The binding properties of cementitious materials using circulating fluidized bed co-fired fly ash and pulverised coal fly ash

Wei-Ting Lin,Krzysztof Miernik,Michał Łach,An Cheng,Kinga Korniejenko,T Tracz,T Zdeb,K Mróz

doi:10.1051/matecconf/202032201003

Wei-Ting Lin, Krzysztof Miernik + Show 6 more

Open Access

https://doi.org/10.1051/matecconf/202032201003

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Abstract

This study aims to investigate the binding properties of co-fired fly ash (CFFA) in paste and mortar specimens. Paste specimens containing various CFFA proportions (25%, 50%, 75%, 100% by weight of cement) were conducted and evaluated using setting time tests, water demand tests and compressive strength tests. Mortar specimens containing various CFFA and Pulverised coal fly ash (PCFA) proportions (10%, 20%, 30% by weight of cement) were also conducted and compared with regard to flowability and compressive strength. The test results indicated that the water demand increased as the amount of CFFA replacement increased on the flow level at 110±3%; this is due to the higher ignition loss (L.O.I.). Higher L.O.I. values mean that there are more unburned carbon particles in the CFFA and that most of these carbon particles are porous. The compressive strength of mortar specimens decreased as the amount of CFFA replacement increased. Compared to the chemical compositions of cement (C3S, C2S), the main components of CFFA (Ca(OH)2, CaCO3, CaO) have lower crystalline strength and compactness. Therefore, the higher amount of CFFA replacement would inevitably cause a reduction of the cement contents of specimens, thereby reducing the compressive strength of the mortar specimens. Thus, an appropriate amount of superplasticiser and CFFA replacement in the mixture is useful with regard to the binding properties of cementitious materials.

Highlights

Green energy and environmental protection are two major issues of the global energy industry which are important concerns in the world
The fluidity of the co-fired fly ash (CFFA) specimens decreased with increases in the proportion of CFFA replacement
The comprehensive conclusion is as follows: 1. Flow test results show that the inclusion of Pulverised coal fly ash (PCFA) in mortar specimens would help improve workability; CFFA in specimens would reduce the workability significantly

Summary

Introduction

Green energy and environmental protection are two major issues of the global energy industry which are important concerns in the world. Energy demand has increased day by day due to increases in living standards and demand, and energy production is one of the main sources of environmental pollution [1, 2]. Around 80% of global energy is provided through the burning of fossil fuels, which emits a large amount of carbon dioxide (CO2) as greenhouse gases. This is one of the main causes of global warming. The main reserves of fossil fuels in the world are primarily coal. How to improve the efficiency of coal combustion and reduce pollution is a matter of great significance to the energy industry [5]

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