SEM-EDX showed no maleficent portlandite
phase in the contact zone between fibers and the matrix, which explained enhanced durability of GRG modified with metakaolin (Brandt & Glinicki, 2003).
dihydrate [H.sub.2]O 2[H.sub.2]O Calcium oxide CaO CaO Chemical Name Cement Notation Mineral Name Tricalcium [C.sub.3]S Alite Silicate Dicalcium [C.sub.2]S Belite Silicate Tricalcium [C.sub.3]A Aluminate Aluminate Tetra calcium [C.sub.4]AF Ferrite Aluminoferrite Calcium hydroxide CH Portlandite
Calcium sulfate CS[H.sub.2] Gypsum dihydrate Calcium oxide C Lime
 found that, after 90 days' curing, 15 mass per cent replacement of PC by metakaolin reduced the portlandite
content of the cured paste to between 6 and 24 mass per cent of its value for the control paste, depending on the quality and particle size of the metakaolin.
Free lime will react with moisture to form portlandite
, identifiable by a weak and possibly broad diffraction peak at d-spacing of 0.490 nm (18.07[degrees] 2-[theta]).
content that was not consumed (free in solution) was determined by sucrose extraction and acid titration.
2012d) and binder chemistry under the specific conditions of the test, rather than in service, especially related to the absence of portlandite
as a reaction product in these binders.
Ca[(OH).sub.2] OH stretching is evidenced on the band at 3693 [cm.sup.-1] for Bogota, 3699 [cm.sup.-1] for Villa de Leyva and at 3695 and 1441 [cm.sup.-1] for Barichara.
High Si[O.sub.2] activity enables Si[O.sub.2] to bind free Ca[(OH).sub.2] (portlandite
) in hardened cement paste.
Image analysis has been successfully used in previous studies7 9 to assess the amount of portlandite
in mortar as well as the geometrical parameters of the particles (size, shape, etc.).
5, it was estimated that the main minerals of the expanded-clay lightweight concrete produced from the mixture C are ettringite, dolomite, silica, calcite, portlandite
, sunstone and cement minerals.
As mentioned above, hydration products of PC contain CH (portlandite
, CH) and almost amorphous calcium silicate hydrate (C-S-H).
The hydrated products of [C.sub.3]A were [C.sub.3]A.6[H.sub.2]O (97%) and portlandite