A correct assessment of the pathologies that can affect a reinforced concrete structure is required in order to define the repair procedure. This work addresses the challenge of quantifying chlorides and sulphates directly on the surface of concrete. The quantification was carried out by means of X-ray fluorescence analysis on the surface of concrete specimens at different points with portable equipment. Concrete prisms were made with different amounts of NaCl and Na₂SO₄. To avoid the influence of coarse aggregate, a qualitative estimate of the amount of coarse aggregate analyzed has been made, although the results show that there is no significant influence. Monte Carlo simulations were carried out in order to establish the necessary number of random analyses of the mean value to be within an acceptable range of error. In the case of quantifying sulphates, it is necessary to carry out six random analyses on the surface, and eight measurements in the case of quantifying chlorides; in this way, it is ensured that errors are below 10% in 95% of the cases. The results of the study highlight that a portable XRF device can be used in situ to obtain concentrations of chlorides and sulphates of a concrete surface with good accuracy. There is no need to take samples and bring them to a laboratory, allowing lower overall costs in inspection and reparation works.

It is commonly mentioned that corrosion of steel in presstressed concrete can induce brittle failure. It is also understood that in order to estimate the presstressed structures service life is necessary to study the pitting factor that compares the maximum corrosion pit depth with the section loss by homogeneous corrosion. Results are presented on corrosion tests to measure the corrosion depth in tendons in contact with water. In present paper, a statistical analysis has been carried out in order to obtain the pitting factor for different cross sections submerged in water. The results indicate that the pitting factor value varies between 1.20 and 1.85 depending on the confidence interval considered, which can significantly reduce the service life of the presstressed tendons as long as the exposure conditions are those set out in this study.

The number of reinforced concrete structures subject to anoxic conditions such as offshore platforms and geological storage facilities is growing steadily. This study explored the behaviour of embedded steel reinforcement corrosion under anoxic conditions in the presence of different chloride concentrations. Corrosion rate values were obtained by three electrochemical techniques: Linear polarization resistance, electrochemical impedance spectroscopy, and chronopotenciometry. The corrosion rate ceiling observed was 0.98 µA/cm², irrespective of the chloride content in the concrete. By means of an Evans diagram, it was possible to estimate the value of the cathodic Tafel constant (b_c) to be 180 mV dec⁻¹, and the current limit yielded an i_lim value of 0.98 µA/cm². On the other hand, the corrosion potential would lie most likely in the −900 mV_Ag/AgCl to −1000 mV_Ag/AgCl range, whilst the bounds for the most probable corrosion rate were 0.61 µA/cm² to 0.22 µA/cm². The experiments conducted revealed clear evidence of corrosion-induced pitting that will be assessed in subsequent research.