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.
|Title of host publication||The Proceedings of 34th Annual Cement and Concrete Science Conference and Workshop on Waste Cementation|
|Number of pages||5|
|Publication status||Published - 16 Sep 2014|
|Event||34th Annual Cement and Concrete Science Conference and Workshop on Waste Cementation - UK, Sheffield , United Kingdom|
Duration: 14 Sep 2014 → 17 Sep 2014
|Conference||34th Annual Cement and Concrete Science Conference and Workshop on Waste Cementation|
|Period||14/09/2014 → 17/09/2014|