Probabilistic Evaluation of Carbonation Induced Deterioration in Prestressed Concrete Structures
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Series/Report no.:2015 Fall Undergraduate Research Student Poster Forum. 9th
Reinforced concrete is one of the most universally used building materials, since it has a high capacity under compression, handles tensile stresses through steel reinforcement, and provides lasting durability. This durability, however, is reduced by a form of deterioration, called carbonation, caused by the reaction of carbon dioxide with the constituents inside concrete. This form of deterioration alters concrete’s material properties by increasing the compressive strength, but reducing its deformation ability. Moreover, when carbonation is coupled with chloride penetration, it destroys the natural concrete protection surrounding reinforcing steel. These alterations decrease the structural capacity of concrete members by increasing the likelihood of brittle failure and reducing the steel cross-sectional area. Carbonation is expected to be of increasing concern for structural engineers, because deterioration can lead to premature failure before the intended design life. The purpose of this study is to assess the impact of concrete carbonation and chloride penetration on the service life of reinforced concrete structures and to evaluate the probability of structural failure with respect to design and environmental exposure. Since carbonation is a stochastic phenomenon with highly variable properties, a probabilistic model is developed to determine the time to corrosion initiation, which required a comprehensive literature review of previous models and experimental research . Previous models have analyzed this rate at the material level, focusing on maintenance rather than structural reliability. However, this study extends the effects of carbonation past the serviceability to the durability level by integrating the carbonation progression into a finite element model of a prestressed concrete pile. With the increasing amount of atmospheric carbon dioxide, concrete carbonation is expected to reduce future durability of concrete infrastructure. It is expected that this research will provide more information on whether current concrete design standards provide adequate structural reliability with the expected deterioration caused by concrete carbonation.
Engineering and Architecture
Academic Major: Civil Engineering