Test of accelerated carbonation
A carbonation station, with content moisture and controlled carbon dioxide, allows the
accelerated material carbonation containing cement. The fall of pH pulled by the
carbonation can be detected by a pH-metric indicator (phenolphthalein). The quantity of
carbon dioxide fixed by the cementing matrix during the carbonation can be followed by
gammadensimetry via the induced voluminal weight saving. This last non-destructive test
allows a carbonation follow-up of concretes in time (kinetic) and spaces (profile).
Permeability to gas measurement
The Cembureau's permeameter has the aim of measuring the permeability (in m˛) to oxygen of
a specimen of concrete. We thus injects oxygen under pressure through the material
sample. The measured flow makes possible to deduce the material permeability.
Ions chloride migration test
This test allows the determination of the chloride diffusion coefficient in
non-steady-state conditions using a migration test under electric field.
A cylindrical concrete sample
is placed in the center of a cell made up of two compartments which contain,
in the downstream compartment, a free from chlorides solution (basic solution),
and on the upstream
compartment, a NaCl solution. At the extremity of each compartment, there is an (metal)
electrode connected to a generator of stabilized tension. A potential difference
is applied between these electrodes so that the ions chloride migrate in direction
of the downstream compartment. The test consists in measuring the chloride penetration depth
xd induced by an electric potential difference DE applied during a time
Dt between the sample boundaries. This penetration depth is measured after sample splitting
using a colorimetic method (silver nitrate spraying). The apparent chloride diffusion
coefficient is calculated from DE, Dt and xd.