• Soutsos, Marios
• Sha, Wei
• Vinai, Raffaele
• Rafeet, A. M.

Abstract

Alkali-Activated Concretes (AACs) or Geopolymers (GP) are considered as potential candidates to play the role of binders substituting Portland cement (PC) in concrete. However, these materials differ from PC in terms of fresh properties (setting time, slump), mechanical properties (strength development, elastic features), and mix proportions. Better understanding of these engineering properties can help to design low CO2 footprint AAC formulations for different construction applications. AACs despite demonstrating promising strength and workability potentials, are still not widely used at an industrial scale, mainly due to the lack of a widely accepted standardised mix design method that fulfils the design requirements such as strength, workability and setting time. In this paper, the proportioning of ambient temperature cured AAC produced from pulverised fuel ash (PFA) and ground granulated blast furnace slag (GGBS) activated with a mixture of sodium hydroxide and sodium silicate solution is discussed. The influence of paste content, water to solid ratio (W/S) and binder blend (PFA/GGBS) ratio was studied. It was found that the strength increased with the increase of GGBS content in the blend. The paste content was found to greatly affect the workability of AAC whereas its influence on strength was insignificant in the investigated range. The influence of W/S ratio on strength was found to be insignificant until a certain ratio beyond which a noticeable drop was detected <br/><br/>

Topics

• impedance spectroscopy
• strength
• Sodium
• cement