Probabilistic Method and its Application for Evaluating Carbonation Life of New-Built Concrete Structures

In order to evaluate carbonation life of new-built concrete structures, two kinds of nondestructive methods have been adopted to test the thickness of concrete cover and ultrasonic velocity of new-built structures. Simultaneously a probabilistic method was proposed based on the relationship between accelerated carbonation rate and ultrasonic velocity. This proposed method has been applied to evaluate the carbonation related lives of two new-built tunnels. The results indicate that even at the nearly same environmental and CO2 combining condition, there exists a big difference in probabilistic carbonation lives between two tunnels i.e. the probabilistic lives of Tunnel A and Tunnel B are 94.0% and 82.3% and the corresponding maximum discrepancies are 11.6% and 27.0%, respectively. Thus it can be concluded that the scattered quality of concrete cover is attributed to the difference in construction technique, which eventually leads to the diversity in evaluated probabilistic carbonation life of two tunnels.

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