Durability of alkali-activated fly ash concrete: Chloride penetration in pastes and mortars

Nanoscale heterogeneities in a fractured alkali-activated slag binder: A helium ion microscopy analysis

“…This reveals that the chemistry of the gel binder, particularly the presence of calcium in the GGBS-based gel phases, may play an important role in governing the extent of microcracking. In particular, there are differences in the nature of the percolated pore network associated with sodium-alumino-silicate-hydrate (N-A-S-H) gel in metakaolin and fly ash-activated pastes and calcium-alumino-silicatehydrate (C-A-S-H) gel in GGBS-activated pastes, where the size of the percolating pores diminishes as the system moves toward a calciumrich environment [6]. Hence, using GGBS in AAMs (together with a sodium silicate-based activator) leads to the formation of gel pores (less than 10 nm in diameter) within the C-A-S-H gel matrix together with a depercolated capillary pore network [7].…”

Structural concrete based on alkali‐activated binders: Terminology, reaction mechanisms, mix designs and performance

“…The resistance to chloride penetration allows conclusions to be drawn on the connectivity of the pore network and the potential of chloride‐induced steel corrosion. Zhu et al determined higher chloride penetration depths in pastes and mortars based on AAFA/slag mixes ( w/b = 0.32–0.42) in comparison to PC. With a decreasing w/b ratio, the absolute porosity and the pore connectivity decreases and the chloride penetration is reduced significantly by 40–60%.…”

“…Chloride penetration depths decrease with an increasing amount of hydraulic components since additional mixing water is chemically bound in C─A─S─H phases. Therefore, the number of small pores decreases and that of larger pores increases …”

Influence of calcium content on the atomic structure and phase formation of alkali‐activated cement binder

“…To mitigate the environmental pressure caused by CO 2 emission during cement production, researchers have applied the alkali‐activated material to replace the Portland cement for construction, which can reduce the CO 2 emissions by 80% during the production process . Furthermore, using the alkali‐activated binder can possibly enhance the durability performance of concrete . The raw materials used to prepare the alkali‐activated materials mainly include the metakaolin, granulated blast‐furnace slag, or fly ash .…”