Abstract
The service life prediction of reinforced concrete (RC) structures in marine environment is essential in structural repair and health monitoring. In this paper, a numerical model for predicting the service life of reinforced concrete is first developed which considering the time-varying boundary of chloride concentration, critical chloride concentration and density of corrosion current. Based on the model, the effects of water–cement ratio, reinforcement diameter, concrete cover thickness and critical chloride ion concentration on the service life and deterioration duration of RC structures are investigated. The key factors affecting the service life of reinforced concrete structures are determined. More importantly, based on regression analysis, a new simplified empirical model for predicting the service life of RC structures is also developed. It provides a fast assessment tool for practical engineers. Both the numerical model and empirical model validated are suitable for practical engineering applications. The results show that with the increase of water–cement ratio, the service life of reinforced concrete structure decreases exponentially. And with the increase of the thickness of the concrete cover, the service life, deterioration duration, and safety reserve increase linearly. However, the influence of the diameter of the reinforcing bar on the service life can be ignored.
Highlights
1 Introduction Reinforced concrete (RC) structures are widely used in normal construction projects, such as tall buildings (Fu, 2018, 2021) and bridges (Fu, 2015, 2016) offshore bridges, subsea tunnels, and harbour projects (Pillai et al, 2019; Xu et al, 2019), and for these types of projects, chloride ingress due to marine environment is one of the main factors causing the corrosion of steel bars (Chang et al, 2020; Marks et al, 2015)
Cao et al (2014) and Zhu et al (2017; Zhang et al, 2019) established a mechanical model to predict the service life of RC structures. It is based on analysis of the corrosion mechanism of steel bars considering the thickness of concrete cover (Enright & Frangopol, 1998), the critical value of the chloride concentration (Bastidas-Arteaga et al, 2009; Enright & Frangopol, 1998), and the chloride diffusion coefficient (Pack et al, 2010)
It turns out that the critical chloride ion concentration has a linear relationship with the service life, which is consistent with the results of Muthulingam et al (2014)
Summary
Reinforced concrete (RC) structures are widely used in normal construction projects, such as tall buildings (Fu, 2018, 2021) and bridges (Fu, 2015, 2016) offshore bridges, subsea tunnels, and harbour projects (Pillai et al, 2019; Xu et al, 2019), and for these types of projects, chloride ingress due to marine environment is one of the main factors causing the corrosion of steel bars (Chang et al, 2020; Marks et al, 2015). Stambaugh et al (2018) used the critical value of chloride ion concentration on the surface of steel bars as the service life assessment standard and studied the service life of RC structures in marine environments under different circumstances such as the location and the mix ratio (Jung et al, 2018; Khanzadeh-Moradllo et al, 2015; Mir et al, 2019). Cao et al (2014) and Zhu et al (2017; Zhang et al, 2019) established a mechanical model to predict the service life of RC structures It is based on analysis of the corrosion mechanism of steel bars considering the thickness of concrete cover (Enright & Frangopol, 1998), the critical value of the chloride concentration (Bastidas-Arteaga et al, 2009; Enright & Frangopol, 1998), and the chloride diffusion coefficient (Pack et al, 2010). The models proposed in this paper provide important theoretical support for life assessment of existing projects and optimization of service life design of projects to be built
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