Determination of chemical composition and electrical resistivity of expressed cementitious pore solutions using X-ray fluorescence

Ionic transport in concrete can be described using the formation factor. The formation factor is computed as the ratio of the resistivity of the bulk concrete to the resistivity of the pore solution. As such, calculation of the formation factor requires knowledge of pore solution resistivity. The objective of this study is to use X-ray fluorescence (XRF) to determine the pore solution composition and to calculate the pore solution resistivity from the pore solution composition. The calculated pore solution resistivity is compared to experimentally measured results obtained using a resistivity meter. The results indicate that XRF can be used to accurately determine the composition of the pore solution and this can be used to compute its resistivity. A comparative study on simulated pore solutions was also performed using inductively coupled plasma atomic emission spectroscopy (ICP-AES) to further validate the use of the XRF method to obtain the pore solution composition.