CPD Specifier May 2015 issue September 2015 | Page 57

Outdoor Engineering

Ash is on
the increase
The latest figures on the uses of fly ash and furnace
bottom ash show that not only is ash uptake rising,
but it also continues to be used in a wide variety of
applications. Here, Robert Carroll, Technical Director
at the UKQAA, explains what this means for the
future of a sustainable construction industry...

In 2014, the UK’s coal-fired power stations produced over four and
a half million tonnes of fly ash and almost eight hundred thousand
tonnes of furnace bottom ash, 70 per cent of the fly ash and almost
100 per cent of furnace bottom ash was used by the construction and
engineering industries. What this shows is despite the changing energy
and materials markets, the supply of ash remains consistent and its role
in creating sustainable construction products and materials is vital.
Fly ash and furnace bottom ashes are produced during the combustion
process at coal-fired power stations. Fly ash can be used as an
important constituent in the manufacture of concrete and cement.
It reduces the amount of embodied carbon in the end products and
preserves finite virgin resources. As an effective pozzolana, or binding
material, fly ash also creates robust, durable products, which can
outperform traditional cementitious mixers. Likewise, furnace bottom
ash is an increasingly useful secondary resource, used mostly as an
alternative lightweight aggregate.
In 2014, 54 per cent of the fly ash produced was used in the
manufacture of bound construction products and materials. Of this two
and half million tonnes, over 12 per cent was used in the manufacture
of cement, while 14 and a half per cent was used for Type I&II concrete
additions. Almost 30 per cent was used in concrete blocks, AAC blocks,
grouting, soil stabilisation and hydraulically bound materials. In addition
to these bound uses, almost three per cent of the total amount of fly ash
produced was used for engineering fill and over 15 per cent was used
for land reclamation and other unbound applications.
The wide variety of applications outlined show the diverse technical
uses for fly ash and furnace bottom ash and the broader benefits the
alternative materials can bring. Fly ash and furnace bottom ash create
a breadth of low-carbon, high performance building materials and
products and are instrumental in achieving sustainable building and
infrastructure. What’s more, with approximately 30 per cent of ash
produced being surplus each year and a range of new ash recovery
schemes and research projects underway, the long-term outlook for ash
supply and manufacture remains positive.
For more information on the UKQAA or how you can make use of
fly ash, please visit www.ukqaa.org.uk

UK QUALITY ASH ASSOCIATION

TEL: [phone]

WWW.UKQAA.ORG.UK

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