10 Pages

Accelerated vs. natural corrosion experimental results for remaining life stage forecasting

ByA.A. Torres-Acosta

ABSTRACT: This paper presents the result obtained from an experimental study that evaluated the efficacy of a controlled current system for accelerating corrosion of reinforced concrete elements. In the study, twenty four reinforced concrete beams (10 × 15 × 150 cm) were subjected to a nominal constant current density between 80 and 200 μA/cm2 and was achieved using special circuitry. On the other hand, twenty eight reinforced concrete slabs (15 × 30 × 60 cm) were used for natural corrosion tests. All the specimens were cast with 3% chloride by weight of cement in either a localized or generalized region. The beams were placed in two different environments: constantly wet or dry. The slabs were placed in a constant dry laboratory environment only. Predicted metal loss using Faraday’s Law in the accelerated specimens were compared against actual losses obtained by the gravimetric method. The correspondence between concrete crack propagation and/or pit depth and metal loss was also determined for both methods. Good correlation was obtained between Faradaic and gravimetric losses for both methods. No apparent difference between corrosion parameters (mass loss, crack opening and extension, pit depth) in accelerated and natural corrosion tests were observed, which support the use of such constant current accelerated method for remaining life forecasting.