A review study: The Effect of activator type on the compressive basic creep of alkali-activated materials under autogenous condition

• The compressive basic creep at the macro scale is determined by the microphases of hydration products, anhydrous particles and pores. • The burger model is available for the prediction of the compressive basic creep evolution. • The creep mechanisms in AAMs could interpret more theories besides the water movement at early age and the C-S-H type gel rearrangement at long term. To activate the hydration process and obtain the proper mechanical performance of mineral additions, like Blast-Furnace Slag (BFS), the chemical activation is a commonly used and friendly solution. As the nature of chemical activators affects the microstructure of materials, this paper provides a review of the activator effect on the compressive basic creep of alkali-activated materials under autogenous conditions. The impact of a partial replacement of BFS by Fly Ash (FA) is also reviewed. Alkali-activated BFS mortar and concrete generally show a larger creep than traditional Portland cement systems. The combined activation of sodium silicate and sodium hydroxide is reported to lead the higher mechanical performance and lower creep. It can be explained by its denser matrix characterized by a lower porosity and lower pore connectivity, possibly limiting the water movement, one of the basic creep driving mechanisms at early age. Another reason is related to the C-S-H type gels’ mobility at long term. Among the sole use of activator types, the sodium silicate performs better, followed by the sodium hydroxide, sodium carbonate, and sodium sulfate. A small content of FA leads to a lower mechanical performance and higher creep magnitude at long term.