This protocol describes the procedure to express fresh pore solution from cementitious systems and the measurement of its ionic composition using X-ray fluorescence. The ionic composition can be used to calculate pore solution electrical resistivity, which can be used, together with concrete electrical resistivity, to determine the formation factor.
Total time
~4–6 hours per sample (including XRF analysis and calculations)
Steps
1
Express pore solution from cementitious material
Apply controlled pressure to fresh cementitious samples to extract interstitial pore solution. Collect expressed liquid for subsequent analysis.
▶ 01:05
2
Assemble containers for solution storage
Prepare and assemble appropriate vessels to safely contain and preserve expressed pore solution samples prior to analysis.
▶ 02:44
3
Develop XRF application and calibrate instrument
Configure X-ray fluorescence measurement parameters and perform calibration using reference standards relevant to cementitious pore solution composition.
▶ 03:16
4
Perform XRF analysis of pore solution
Analyze pore solution samples using calibrated XRF to quantify elemental and ionic concentrations.
▶ 03:41
5
Calculate ionic concentrations from XRF data
Convert XRF spectroscopic measurements into quantitative ionic composition (molarity/molality) using appropriate stoichiometric relationships.
▶ 04:25
6
Calculate pore solution electrical resistivity
Use ionic concentration data to compute electrical resistivity of the pore solution via conductivity models.
▶ 04:56
7
Interpret and report results
Present calculated ionic composition, resistivity values, and formation factor data with discussion of findings.
▶ 05:08