Model of Reinforced-Concrete Structure Deformation Under Combined Effect Carbonation and Chloride Corrosion

International Multi-Conference on Industrial Engineering and Modern technologies

Valiev, S.N.^1 ; Ovchinnikov, I.G.^2 ; Vasilyev, Y.E.^1 ; Tao, Chen^1

Moscow Automobile and Road Construction State Technical University (MADI), Russia^1

Saratov State Technical University, Russia^2

关键词: Corrosion intensity;    Corrosive environment;    Deformation modeling;    Mechanical qualities;    Piecewise functions;    Reinforcement corrosion;    Sensitive parameter;    Tension and compression;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/463/3/032093/pdf
DOI  :  10.1088/1757-899X/463/3/032093

来源: IOP

【 摘 要 】

The present paper is devoted to creating a model of deformation and destruction of reinforced-concrete bridge structures subject to combined effect of load and carbonation (caused by presence of carbon dioxide), and chloride corrosion triggered by salts used for bridge road deicing. The model is a hybrid of several models such as loading model; structural element model (pier, beam, roadway slab, span structure); impact models of two corrosive environment triggering carbonation and chloride corrosion; concrete deformation models (considering transformations caused by impact of various corrosive environments); reinforcement corrosive wear model. Concrete deformation model is created with due regard to nonlinearity of its operation and variable tension and compression resistance. Impact functions are the tool that demonstrates the influence carbonation and chloride corrosion have on the structure. Corrosive wear model is built as a piecewise function with a zero value at the incubation period, and as a power function after the end of the incubation period. Due to combined effect of carbonation and chloride corrosion, critical content of chlorides (which triggers reinforcement corrosion) drops twofold at a critical value of the carbonation process parameter, and this significantly shortens the incubation period. The paper describes the generalized model bridge pier deformation due to combined effect of load, carbonation, and chloride corrosion. The model shows the stages of how pier operates during ingression of the chloride-containing environment and carbon dioxide to the cross-section from the outside. The pier calculation methodology has three phases: loading, pier submerging into a corrosive environment (which causes chloride corrosion and carbonation), and pier deformation over time with due regard to change of mechanical qualities of concrete (caused by carbonation and chloride corrosion), and to reinforcement corrosion. When calculating pier deformation over time, time steps are used; step duration is set to ensure that changes of all step-sensitive parameters (chloride content, stress) would not exceed the preset limits. Following the methodology, a software package was developed, which enabled to calculate the values of the vertically loaded pier under combined effect of a chloride-containing environment and carbonation. As a result, it was found that under the combined effect of chlorides and carbon dioxide, the incubation period of reinforcement corrosion shortens significantly, corrosion intensity grows, and pier durability turns out to be shorter than when impacted by each factor separately.