Alkali activated fuel ash and slag mixes: optimization study from paste to concrete building blocks

A. Rafeet, R. Vinai, W. Sha, M. Soutsos

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Abstract

    Alkali activated binders, based on ash and slag, also known as geopolymers, can play a key role in reducing the carbon footprint of the construction sector by replacing ordinary Portland cement in some concretes. Since 1970s, research effort has been ongoing in many research institutions. In this study, pulverized fuel ash (pfa) from a UK power plant, ground granulated blast furnace slag (ggbs) and combinations of the two have been investigated as geopolymer binders for concrete applications. Activators used were sodium hydroxide and sodium silicate solutions. Mortars with sand/binder ratio of 2.75 with several pfa and ggbs combinations have been mixed and tested. The optimization of alkali dosage (defined as the Na2O/binder mass ratio) and modulus (defined as the Na2O/SiO2 mass ratio) resulted in strengths in excess of 70 MPa for tested mortars. Setting time and workability have been considered for the identification of the best combination of pfa/ggbs and alkali activator dosage for different precast concrete products. Geopolymer concrete building blocks have been replicated in laboratory and a real scale factory trial has been successfully carried out. Ongoing microstructural characterization is aiming to identify reaction products arising from pfa/ggbs combinations.
    Original languageEnglish
    Title of host publicationThe Proceedings of 34th Annual Cement and Concrete Science Conference and Workshop on Waste Cementation
    Pages349-353
    Number of pages5
    Publication statusPublished - 16 Sep 2014
    Event34th Annual Cement and Concrete Science Conference and Workshop on Waste Cementation - UK, Sheffield , United Kingdom
    Duration: 14 Sep 201417 Sep 2014

    Conference

    Conference34th Annual Cement and Concrete Science Conference and Workshop on Waste Cementation
    CountryUnited Kingdom
    CitySheffield
    Period14/09/201417/09/2014

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