A statistical reappraisal of the relationship between liquid limit and specific surface area, cation exchange capacity and activity of clays

Effect of physicochemical characteristics on the use of clays from Kindia (Guinea) in ceramic compositions

“…These values are close to those of kaolinite‐illite mixed clays, indicating a classification of ABD and ARD as moderate plastic clays 19,15 . Upon the classification of clays, many studies have also demonstrated a close relationship between Atterberg or consistency limits and properties such as compressibility, strength, and permeability 20,21 . The latter is correlated with the activity and therefore to the chemical reactivity of the material.…”

“…The latter is correlated with the activity and therefore to the chemical reactivity of the material. Since the pore‐water suction values are similar at the liquid limit, this means that the ratio of adsorbed water to clay surface area should be about the same at the liquid limit 21 …”

“…The exothermic peaks at 990°C for ABD and at 1000°C for ARD are from the structural reorganization of dehydroxylated clay minerals and the onset of sintering. In the upper‐temperature range, the physico‐chemical transformations were interpreted by many authors: ‐ at the onset of recrystallization, a transient spinel phase is formed with the nucleation and growth of small mullite crystals; 25,26 ‐ aluminum ions are returning in VI fold coordinated structural units, meaning more stable structural characteristics; 27,28 ‐ the formation of reactive amorphous silica; 29 ‐ the transition from metakaolinite to coexisting alumina rich domains and silica‐rich domains 21,20 …”

“…We can point out the higher amount of muscovite in ABD in comparison to that in ARD. The mineral muscovite has a well‐known role in densification, since it favors the formation of a liquid phase, following the SiO 2 ‐Al 2 O 3 ‐K 2 O ternary phase diagram 21,30,31 . Besides, the role of a high amount of fine quartz must be considered since it is also involved in the accentuation of densification due to the small size of particles.…”

“…19,15 Upon the classification of clays, many studies have also demonstrated a close relationship between Atterberg or consistency limits and properties such as compressibility, strength, and permeability. 20,21 The latter is correlated with the activity and therefore to the chemical reactivity of the material. Since the pore-water suction values are similar at the liquid limit, this means that the ratio of adsorbed water to clay surface area should be about the same at the liquid limit.…”