Use of X-Ray Fluorescence for the Evaluation of Chloride Ion Penetration in Concrete

Chloride ions are the primary aggressive agents responsible for the corrosion of reinforced concrete structures and, consequently, the reduction of their service life, which entails high repair costs. These ions penetrate the concrete through its porous network and depassivate the steel reinforcement, even in small quantities. The adoption of specific binders modifies the cementitious matrix, potentially hindering the progression of these ions. As a chloride detection technique, X-ray fluorescence (XRF) can be employed, which, in addition to identifying the elements present in a sample, allows the creation of intensity distribution maps. Thus, this study aimed to evaluate how the XRF technique can contribute to understanding chloride penetration and to identify which cement types most effectively hinder their advancement. To accelerate chloride ion migration, two methods were employed: ASTM C1202 and NT Build 492. Eight different types of cement were analyzed, and the results indicated high resistance to chloride penetration in cements containing slag and pozzolan, while cements with filler exhibited lower resistance.