The role of water content and paste proportion on physico-mechanical properties of alkali activated fly ash-ggbs concrete
Vinai, R; Rafeet, A; Soutsos, M; et al.Sha, W
Date: 23 October 2015
Journal
Journal of Sustainable Metallurgy
Publisher
Springer Verlag
Publisher DOI
Abstract
t The growth of the construction industry
worldwide poses a serious concern on the sustainability of
the building material production chain, mainly due to the
carbon emissions related to the production of Portland
cement. On the other hand, valuable materials from waste
streams, particularly from the metallurgical industry, are
not ...
t The growth of the construction industry
worldwide poses a serious concern on the sustainability of
the building material production chain, mainly due to the
carbon emissions related to the production of Portland
cement. On the other hand, valuable materials from waste
streams, particularly from the metallurgical industry, are
not used at their full potential. Alkali-activated concrete
(AAC) has emerged in the last years as a promising
alternative to traditional Portland cement-based concrete
for some applications. However, despite showing remarkable strength and durability potential, its utilisation is not
widespread, mainly due to the lack of broadly accepted
standards for the selection of suitable mix recipes fulfilling
design requirements, in particular workability, setting time
and strength. In this paper, a contribution towards the
design development of AAC synthesised from pulverised
fuel ash (60 %) and ground granulated blast furnace slag
(ggbs) (40 %) activated with a solution of sodium
hydroxide and sodium silicate is proposed. Results from a
first batch of mixes indicated that water content influences
the setting time and that paste content is a key parameter
for controlling strength development and workability. The
investigation indicated that, for the given raw materials and
activator compositions, a minimum water-to-solid (w/s)
ratio of 0.37 was needed for an initial setting time of about
1 h. Further work with paste content in the range of
30–33 % determined the relationship between workability
and strength development and w/s ratio and paste content.
Strengths in the range of 50–60 MPa were achieved.
Engineering
Faculty of Environment, Science and Economy
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