scholarly journals Need for Further Development in Service Life Modelling of Concrete Structures in Chloride Environment

2017 ◽  
Vol 171 ◽  
pp. 549-556 ◽  
Author(s):  
Gro Markeset ◽  
Mahdi Kioumarsi
Keyword(s):  
Service Life ◽  
Concrete Structures ◽  
Chloride Environment ◽  
Further Development ◽  
Service Life Modelling

scholarly journals Service life design and modelling of concrete structures – background, developments, and implementation

2018 ◽  
Vol 8 (3) ◽  
pp. 224-245 ◽  
Author(s):  
Mark Gavin Alexander
Keyword(s):  
South Africa ◽  
Service Life ◽  
Current Knowledge ◽  
Concrete Structures ◽  
International Experience ◽  
Durability Design ◽  
Service Life Design ◽  
International View ◽  
Life Design ◽  
Service Life Modelling

The paper presents an overview of current knowledge and progress in service life design and modelling of concrete structures, taking an international view but also giving local examples from South Africa. It raises the question of why service life modelling is needed, and indicates that modern demands for longevity, durability, and sustainability of concrete structures cannot be fulfilled without service life modelling. It addresses the current approaches to durability design and specification and concludes that a move to performance-based approaches is imperative if progress is to be made. Examples from international experience are cited to illustrate progress that has been made. Lastly, the paper discusses ways of moving forward, recognizing that the philosophical bases are already firmly in place in the form of general code formulations, but these need to be converted into useful approaches.

scholarly journals Durability and service life prediction for concrete structures – developments and challenges

2018 ◽  
Vol 149 ◽  
pp. 01006 ◽  
Author(s):  
Mark G Alexander
Keyword(s):  
Service Life ◽  
Life Prediction ◽  
Concrete Structures ◽  
Performance Testing ◽  
Integrated Approach ◽  
Service Life Prediction ◽  
Site Quality ◽  
Concrete Durability ◽  
Durability Prediction ◽  
Service Life Modelling

The paper reviews developments in service life prediction for concrete structures. It indicates the difficulties inherent in rational service life design, in view of the multiple factors and variabilities involved in the process. The paper also emphasises the advantages of performance-based approaches to durability prediction, and considers performance testing, which is critical to achieving intended service life. Such approaches allow service life modelling, which the current prescriptive approaches do not. The concept of ‘durability indicators’ is covered, with a practical example showing how this can be used to improve concrete durability in construction. The paper also stresses the importance of an ‘integrated approach’ to durability specifications, performance-based predictions, and site quality control.

Effect of the ITZ Damage on Durability of Reinforced Concrete in Chloride Environment

1994 ◽  
Vol 370 ◽  
Author(s):  
Raoul François ◽  
Ginette Arliguie
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Concrete Structures ◽  
Operating Conditions ◽  
Reinforced Concrete Structures ◽  
Actual Operating ◽  
Chloride Environment ◽  
Concrete Elements ◽  
Transfer Properties ◽  
Salt Fog

AbstractThis paper deals with the effect of the ITZ on the service life of reinforced concrete. In the case of reinforced concrete structures, the penetration of chlorides does not depend only on concrete transfer properties but also on the loading applied, on the state of strains and on the exposure to the aggressive environment.In order to take into account these different parameters, we have performed experiments on reinforced concrete elements, over a long period. The samples used have to be of an adequate size (3 meters long) and stored in a salt fog in a loading state so as to be representative of the actual operating conditions of the reinforced concrete structures.The bending of the beams leads to the development of cracks which are neither preceded nor accompanied by microcracks, but the cement paste-aggregate interfaces are damaged in the tensile areas.The service loading of reinforced concrete has two consequences : firstly, a cracking with widths ranging between 0.05 mm and 0.5 mm according to the intensity of the mechanical strength applied. Secondly, a damage of the ITZ in the tensile areas causing an increase of chloride penetration directly proportional to the intensity of the stress applied to the beam.The model of the development of corrosion, worked out in relation with time and based on our results, emphasizes the influence of the paste-aggregate interface damage on the duration of the service life.

Influence of Boundary and Initial Condition on Durability of Concrete Structures Exposed to Chloride Environment

2012 ◽  
Vol 166-169 ◽  
pp. 1946-1953
Author(s):  
Xin Gang Zhou ◽  
Fang Zhao
Keyword(s):  
Service Life ◽  
Initial Conditions ◽  
Error Function ◽  
Concrete Structures ◽  
Life Time ◽  
Chloride Penetration ◽  
Analytical Models ◽  
Chloride Ingress ◽  
Chloride Environment ◽  
Penetration Profile

According to investigations of apparent surface chloride contents and chloride penetration profile of concrete structures exposed to chloride environment, the influences of boundary and initial conditions, geometry parameters such as the geometry dimension and section shape, etc. were discussed. Based on the Fick’s second law of diffusion and different boundary and initial conditions, different analytical models to predict the chloride penetration profile in concrete structural members with different boundary and initial conditions were derived. Some calculations examples were made using those analytical models. Computational results show that the boundary and initial conditions have remarkable influences on chloride penetration profile and service life time of concrete structures. Using prevailing error-function solution model based on the semi-infinite assumption of chloride ingress, the prediction of service life time of concrete structures are over evaluated, in particular for the steel reinforcement in corner of the section. Some modify coefficients should be taken into consideration, concerning the influences of boundary and initial conditions.

scholarly journals The Influence of Supplementary Cementitious Materials on Climate Impact of Concrete Structures Exposed to Chlorides

2018 ◽  
Vol 58 (1) ◽  
pp. 77-93 ◽  
Author(s):  
Nadia Al-Ayish ◽  
Otto During ◽  
Katarina Malaga ◽  
Nelson Silva ◽  
Kjartan Gudmundsson
Keyword(s):  
Fly Ash ◽  
Service Life ◽  
Concrete Structures ◽  
Cementitious Materials ◽  
Climate Impact ◽  
Design Approach ◽  
Supplementary Cementitious Materials ◽  
Minimum Cover ◽  
Chloride Environment ◽  
Cover Thickness

Abstract Addition of fly ash or GGBS in concrete has shown to increase the durability and thus the service life of concrete structures exposed to chlorides. Currently, the durability relies on regulations, which beside a minimum cover thickness also put constraint on amount and type of SCM in different environments. Swedish regulations do not, however, consider the actual durability of different binders. As a consequence, a LCA might be misleading. This paper investigates the climate impact of concrete with SCM in chloride environment. Current prescriptive design approach is compared with a performance based service life approach and applied to bridge parts.

scholarly journals A Theoretical Framework for Service Life Prediction of Reinforced Concrete Structures in Chloride Environment using Load Factors

2021 ◽  
Vol 11 (1) ◽  
pp. 6806-6809
Author(s):  
A. A. Pathan ◽  
G. B. Khaskheli ◽  
A. S. Qureshi
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Concrete Structures ◽  
Theoretical Framework ◽  
Reinforced Concrete Structures ◽  
Chloride Ingress ◽  
Load Factors ◽  
Concrete Failure ◽  
Loading Effects ◽  
Chloride Environment

Service life modeling of reinforced concrete structures in a chloride environment is mainly performed without considering the loading effects. Different loading effects can produce different service life results. This study presents a theoretical framework for the modeling of the service life of reinforced concrete structures in a chloride environment using loading factors, showing that, depending on the loading nature (either compression or tension), different diffusion results could be obtained. This paper also highlights various approaches to service life modeling, such as the deterministic, probabilistic, and semi-probabilistic, which consider different ways to estimate the service life of reinforced concrete structures in chloride environments. The importance of various distributions for the input parameters in the chloride ingress modeling was examined. The proposed framework includes a procedure to estimate the probability of concrete failure in chloride environments.

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