Time-varying behavior and its coupling effects with environmental conditions and cementitious material types on surface chloride concentration of marine concrete

2021 ◽  
Vol 303 ◽  
pp. 124578
Author(s):  
LuFeng Yang ◽  
Lu Wang ◽  
Bo Yu
Keyword(s):  
Environmental Conditions ◽  
Chloride Concentration ◽  
Cementitious Material ◽  
Time Varying ◽  
Coupling Effects ◽  
Marine Concrete

Probabilistic Model of Corrosion in Reinforced Concrete Structures Considering Coupling Effects of Influence Factors

2013 ◽  
Vol 671-674 ◽  
pp. 740-745
Author(s):  
Xiao Gang Zhang ◽  
Jiao Wang
Keyword(s):  
Probabilistic Model ◽  
Moment Method ◽  
Influence Factors ◽  
Concrete Structures ◽  
Chloride Concentration ◽  
Corrosion Process ◽  
Chloride Ingress ◽  
Coupling Effects ◽  
The Third ◽  
Third Moment

A probabilistic model of the chloride-induced corrosion process is provided in this paper. Based on the Third-moment method, the uncertainty of various influence factors and the coupling effects of them are concerned. Considering the corrosion process as a statistic process, the probability of corrosion initiation at certain time can be obtained. Moreover, the effect of micro-crack in chloride ingress is taken into account, too. Due to the results of stochastic analysis, the surface chloride concentration is the most important factor that affects the corrosion probability, while the thickness of concrete cover, chloride diffusion coefficient, environmental relative humidity, critical threshold chloride concentration, micro-crack rate, water-to-cement ratio and temperature are also important factors. And the Third-moment method is proved to be reasonable in the durability assessment of corrosion-induced concrete structure. The results in this paper can be used to predict the rest life of corrosion-induced concrete structures.

A Study of the Preparation and Properties of the Concrete for the Bearing Platform of the Xiamen-Zhangzhou Sea-Spanning Bridge

2013 ◽  
Vol 357-360 ◽  
pp. 659-666
Author(s):  
Hong Mei Hu ◽  
Hao Wang ◽  
Rong Gui Du ◽  
Bo Shen Zheng ◽  
Yun Kun Yi ◽  
...  
Keyword(s):  
Fly Ash ◽  
Optimal Design ◽  
Environmental Conditions ◽  
High Performance ◽  
High Performance Concrete ◽  
Chloride Diffusion ◽  
Mass Concrete ◽  
Concrete Mix ◽  
Marine Concrete ◽  
Main Bridge

In light of the requirement of mass concrete for the bearing platform of the main tower of the Beicha Main Bridge of the Xiamen-Zhangzhou Sea-spanning Bridge, and in view of the hostile environmental conditions for the project, a study was conducted on the technology of preparing high-performance marine concrete for the bearing platform of the sea-spanning bridge in order to control concrete temperatures and achieve the desired durability for the bridge. With an optimal design which features the binary admixture of fly ash and slag and an optimal concrete mix ratio, high-performance concrete with lower hydration heat and strong resistance to chloride diffusion and cracking was successfully developed for the bearing platform of the sea-spanning bridge.

scholarly journals Experimental Investigation on Chloride Diffusion Coefficient of Self-compacting Concrete in the Oman Sea

2020 ◽  
Author(s):  
Naser Nosratzehi ◽  
Mahmoud Miri
Keyword(s):  
Diffusion Coefficient ◽  
Environmental Conditions ◽  
Chloride Concentration ◽  
Chloride Ion ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Atmospheric Conditions ◽  
Self Compacting Concrete ◽  
Normal Concrete ◽  
Oman Sea

Chloride ion penetration is an important parameter influencing the service life of a concrete structure, especially in aggressive environments. Severe chloride-induced corrosion of reinforced concretes has been reported in the southern part of Iran in the region of Oman Sea. In this paper, the effect of different environmental conditions of the Oman Sea on chloride penetration and mechanical properties of self-compacting concrete (SCC) and normal concrete (NC) is investigated. For this purpose, a number of prismatic specimens were exposed to various environmental conditions such as tide, submersion and atmospheric conditions. Surface chloride concentration and diffusion coefficient of SCC in these zones were calculated based on Fick’s second law, at 28, 90 and 150 days and compared with NC. Based on the values obtained in this study, relationships are proposed for concrete permeability and surface chloride of self-compacting concrete (SCC) at different ages in different aggressive environments. By determining the corrosion time based on these relations, it is observed that for a given water-to-cement ratio, the self-compacting concrete (SCC) has higher durability compared to normal concrete (NC).

scholarly journals Prediction of surface chloride concentration of marine concrete using ensemble machine learning

2020 ◽  
Vol 136 ◽  
pp. 106164 ◽  
Author(s):  
Rong Cai ◽  
Taihao Han ◽  
Wenyu Liao ◽  
Jie Huang ◽  
Dawang Li ◽  
...  
Keyword(s):  
Machine Learning ◽  
Chloride Concentration ◽  
Ensemble Machine Learning ◽  
Marine Concrete

Study on Box-Jenkins Method of Prediction of Chloride Concentration of Marine Concrete Structures

2013 ◽  
Vol 351-352 ◽  
pp. 1629-1636
Author(s):  
Er Ju Li ◽  
Xin Gang Zhou
Keyword(s):  
Life Prediction ◽  
Prediction Models ◽  
Time Series Prediction ◽  
Concrete Structures ◽  
Model Identification ◽  
Chloride Concentration ◽  
Prediction Method ◽  
Parameter Estimate ◽  
Test Model ◽  
Marine Concrete

The paper introduces life prediction models and existing questions of marine concrete structures exposed to chloride environment; Theory of Box-Jenkins time series prediction method is put forward to analyze the change law of chloride concentration of reinforcemnet surface of marine concrete structures along with time; Stationary test, model identification and parameter estimate are introduced; Modeling process and best model identification are discussed by means of analyzing laws of chloride concentration changing with time, and predicts using the best model. Analysis results show that the prediction model built by Box-Jenkins method has simple form and high prediction accuracy. Whats more, future chloride concentration can be well predicted by history values without determining specific values of durability parameters.This is a new method of life prediction of marine concrete structures.

Study on High Amount Mineral Admixtures Concrete Performance

2013 ◽  
Vol 357-360 ◽  
pp. 667-670
Author(s):  
Zhi De Huang
Keyword(s):  
Chloride Ion ◽  
Cementitious Material ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Material System ◽  
Ion Permeability ◽  
Main Research ◽  
Binder Ratio ◽  
Marine Concrete ◽  
Water Binder Ratio

Depended on Qingdao Bay Bridge construction, large amount mineral admixture replacing cement has been conducted systematical research aiming at marine concrete, main control index is chloride ion permeability resistance. The main research contents concrete working, mechanical properties and chloride ion permeability resistance at low water binder ratio and large amounts mineral admixture. Measures and adjustment are proposed for marine concrete construction control and cementitious material system that using amount mineral admixtures and low water binder ratio.

Study on Chloride Diffusion Parameters of Concrete Based on the Field Investigation of Harbor Engineering in South China

2015 ◽  
Vol 744-746 ◽  
pp. 1199-1206
Author(s):  
Zhi Hong Fan ◽  
Da Gen Su ◽  
Sheng Nian Wang
Keyword(s):  
South China ◽  
Chloride Concentration ◽  
Surface Concentration ◽  
Field Investigation ◽  
Chloride Diffusion ◽  
Solid Core ◽  
Electrochemical Testing ◽  
Diffusion Parameters ◽  
Fluctuation Range ◽  
Marine Concrete

Based on the durability investigation on marine concrete structures in South China, the surface chloride concentration and the critical chloride concentration inducing reinforcement corrosion were researched. The surface concentration under the marine environment in South China was analyzed by solid core tests on the harbors with different service ages, and the fluctuation range of surface concentration ranges from 0.2% to 1.1%. Through electrochemical testing and appearance investigation, the value of the critical chloride concentration in concrete components is studied, which is in the range of 0.0518% to 0.0824% by mass of concrete.

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