Steam sorption test on saltworks solutions imposing desired relative moisture: the
differences in mass weighed during the test make possible to obtain the desorption and
adsorption kinetics. One can deduce the equilibrium water contents to relative moistures
considered, as well as the porous structure of the HSC. The sorption device includes a
23°C thermostated bath and desiccators containing the samples, above a saltworks saturated
solution imposing desired relative moisture.
The examination under the Sweeping electron microscope allows:
to observe the various hydrates morphology on fractures (secondary electrons mode)
to evaluate the hydration degree of cement on polished surfaces (retrodiffused electrons mode)
Porosity accessible to water measurement
This test makes possible to obtain the global porosity of material, i.e. the relationship
between the total vacuums volume on the sample tested volume. Accessible to water porosity
is an durability indicator. It is directly related to the material resistance.
Porosimetry tests per mercury intrusion
This test makes possible to explore the porosity of a material for sizes of pores whose
rays lie between 60 µm and 1,8 Nm. It also makes possible to obtain the porous
distribution of material.
The gammadensimetry is founded on absorption, by the material, of the gamma rays emitted
by a Cesium Cs137radioactive source. This absorption follows the Lambert's law, from which
it is possible to obtain the concrete density. The device used makes possible to
auscultate a cylindrical specimen with various heights thanks to the robot which
vertically moves in the gamma radiation beam. Throughout measurement to a given
height, the specimen is placed in the center of an animated plate which can rotates
around its axis: measurement corresponds then to the average on a concrete section
height equal to the diameter of the beam, i.e. 6mm. The absorption coefficient of
the studied concrete depends on the formulation, of the nature of the various
components, thus in particular of the chemical analysis of cement and filler.
Thus this test makes possible to obtain the hydrous profiles (water content, saturation
rate), the microstructure profiles (porosimetry, density) and the carbonation profiles
(quantity of fixed CO2) on concrete samples, in a laboratory or in-situ.