Influence of temperature and humidity on crack propagation in prestressed concrete box-girder bridges: Experimental study and mechanism analysis

With global climate change, the fluctuations in temperature and humidity have increasingly drawn attention to their effects on prestressed concrete box-girder bridges. This study aims to uncover the specific mechanisms of the temperature-humidity coupling effect on crack propagation and propose a mathematical model for crack propagation based on the fundamental theory of concrete strength. The experimental section systematically investigates the effects of temperature and humidity variations on crack propagation by using prestressed concrete specimens under controlled temperature and humidity conditions. The results indicate that rising temperatures and increased humidity accelerate crack propagation, with their coupling effect significantly enhancing the propagation rate. Further mathematical modeling analysis validates this mechanism, providing a theoretical basis for bridge design and maintenance. This study offers a new perspective on the long-term stability evaluation of prestressed concrete bridges and has important applications for optimizing safety assessments and maintenance strategies. This paper delves into the mechanism of crack propagation in prestressed concrete box-girder bridges under temperature-humidity conditions through experimental methods and theoretical analysis, and proposes a corresponding mathematical model based on concrete strength. The findings not only enhance the understanding of crack propagation mechanisms but also provide theoretical support and engineering references for bridge design and maintenance.