Propagation period modeling and limit state of degradation
Carmen Andrade, David Izquierdo
Abstract
Abstract In the present MC 2010 the propagation period, addressing degradation processes, was not included said due to the lack of data to allow for a sound validation. However, taking account of the propagation period is essential for the assessment of existing reinforced concrete structures. In addition, considering the propagation period is relevant for the probabilistic definition of the service life, as a certain amount of degradation should be produced to result in a condition not fulfilling the design requirements. Regarding reinforcement corrosion, in the present work the model of Tuutti is generalized to nonconstant corrosion rates by considering a sequence of periods with each having a constant corrosion rate. Possible models for the calculation of the time to cracking are commented, together with the consideration of a possible limit state related to damage level. Regarding other of deterioration processes related to the concrete material itself, attempts to model these have been very limited and much less attention has been paid to characterize their rate. These processes include: alkali‐silica reaction or sulfate attack, acid or leaching by pure waters and frost attack. In the present article, such attacks are modeled through an initiation period followed by a propagation period. Their rate of deterioration can either be considered constant or also as a sequence of shorter consecutive linear time periods.