Calcite is a compound that is present in hydrated cementitious materials when
carbonation of portlandite occurs or when limestone constituents are used. The quantification of its
content in cementitious systems is then frequently necessary.
Thermogravimetry (TG) measures the change in mass of a material (as a function of time) over a
temperature range using a predetermined heating rate. It can be applied to estimate calcite content in
the hydrated cement system, considering the temperature range at which it decomposes and releases
carbon dioxide. However, the quantification is not easy because the onset of this decomposition is a
function of many variables. The tangential method over the TG signal or the integration method
over the derivative TG curve (DTG) are usually used to discount the background over the
temperature range at which calcite decomposes.
However, consistent underestimation of compounds is frequently described. The reasons for this are
unclear and some hypothesis are discussed in this paper. Additionally, experimental quantitative TG
of cement paste and aggregate containing calcite and diluted with low contents of analytical calcite
are compared with the expected contents, as a calibration method regarding calcite content in the
samples is given to improve the reliability of the results
