Service life modelling

2014 ◽  
pp. 679-714 ◽  
Keyword(s):  
Service Life ◽  
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.

scholarly journals Impact of Water Holding Capacity and Moisture Content of Soil Substrates on the Moisture Content of Wood in Terrestrial Microcosms

Forests ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 485 ◽  
Author(s):  
Christian Brischke ◽  
Friedrich L. Wegener
Keyword(s):  
Service Life ◽  
Moisture Content ◽  
Water Saturation ◽  
Wood Moisture ◽  
Durability Testing ◽  
Species Specific ◽  
Water Holding ◽  
Terrestrial Microcosms ◽  
Protective Effectiveness ◽  
Service Life Modelling

Terrestrial microcosms (TMCs) are frequently used for testing the durability of wood and wood-based materials, as well as the protective effectiveness of wood preservatives. In contrary to experiments in soil ecology sciences, the experimental setup is usually rather simple. However, for service life prediction of wood exposed in ground, it is of imminent interest to better understand the different parameters defining the boundary conditions in TMCs. This study focused, therefore, on soil–wood–moisture interactions. Terrestrial microcosms were prepared from the same compost substrate with varying water holding capacities (WHCs) and soil moisture contents (MCsoil). Wood specimens were exposed to 48 TMCs with varying WHCs and MCsoil. The wood moisture content (MCwood) was studied as well as its distribution within the specimens. For this purpose, the compost substrate was mixed with sand and peat and its WHC was determined using two methods in comparison, i.e., the “droplet counting method” and the “cylinder sand bath method” in which the latter turned out advantageous over the other. The MCwood increased generally with rising MCsoil, but WHC was often negatively correlated with MCwood. The distance to water saturation Ssoil from which MCwood increased most intensively was found to be wood-species specific and might, therefore, require further consideration in soil-bed durability-testing and service life modelling of wood in soil contact.

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