Q2. What are the effects of carbonation on RC structures?
The changes in environmental temperature, relative humidity and carbon dioxide concentration can increase corrosion risks resulting in more widespread corrosion damage and loss of structural safety.
Q3. What are the important factors considered in a climate change study?
The most important factors considered in such a study are: carbon dioxide, methane and nitrous oxide emissions; global population growth; introduction of new and clean technologies leading to the reduction of CO2 emissions; and use of fossil sources of energy.
Q4. What is the role of carbonation in the maintenance of RC structures?
the effect of atmospheric CO2 concentration change and global warming on both chloride ingress and carbonation should be considered the long-term management of RC structures.
Q5. What are the main characteristics of a reinforced concrete structure?
Reinforced concrete (RC) structures are subjected to environmental actions affecting their performance, serviceability and safety.
Q6. What are the common design options for concrete?
The design options generally include the selection of cover, concrete mix, surface coating barriers, extraction, and cathodic protection.
Q7. What is the effect of corrosion on the structural capacity of steel?
Corrosion reduces the structural capacity and the accumulation of corrosion products in the steel/concrete interface generates concrete cover cracking.
Q8. What are the common adaptation measures for new and existing concrete structures?
Adaptation measures for new and existing concrete structures may include:(1) Surface treatments, (2) Realkanization, (3) Extra design cover, (4) Increase concrete durability, (5) Stainless or galvanised steel reinforcement, (6) Corrosion inhibitors, (7) Cathodic protection, and (8) Replace existing cover with new concrete.
Q9. What is the age factor for microclimatic conditions?
The age factor for microclimatic conditions (nm) associated with the frequency of wetting and drying cycles is nm=0 for sheltered outdoor conditions.
Q10. What is the obvious and simplest approach to reduce the impact of changing climate?
While the change of cover is considered as the most straightforward design approach to reduce the impact of changing climate, other options may also include the selection or design of concrete materials to reduce the diffusion coefficient of deleterious substances –i.e. slow the ingress of those substances, and hence delay corrosion of concrete reinforcement.
Q11. What are the main effects of corrosion on RC structures?
The assessment of corrosion effects on RC structures is a difficult task because several deterioration mechanisms interact in the process; ingress of the corroding agent –i.e., chlorides or carbon dioxide, corrosion of reinforcing steel and concrete cover cracking.
Q12. How is the change of temperature and humidity produced by global warming modelled?
The change of temperature and humidity produced by global warming for theupcoming years is modelled by a linear time-variant function.
Q13. What is the final part of the study?
The final part of the study outlines some adaptation strategies for design and repair of RC structures accounting for climate change.
Q14. What are the main actions that lead to corrosion of RC structures?
Among these actions, chloride ingress and carbonation lead to corrosion of reinforcing bars that reduces the service life of RC structures.
Q15. how long does global warming reduce the time to failure of a rc bridge?
The results showed that global warming can reduce the time to failure by up to 31%, or shorten service life by up to 15 years for moderate levels of aggressiveness.
Q16. What is the simplest way to describe the interaction between the three physical processes?
The adopted chloride ingress model considers the interaction between three physical processes: chloride ingress, moisture diffusion and heat transfer.
Q17. what is the proposed methodology for a RC bridge?
The proposed methodology is illustrated with a numerical example that studies the effects of climate change on the structural reliability and time to failure of a RC bridge girder placed in a chloride-contaminated environment.
Q18. What is the way to represent the weather variables?
Taking into account the simplicity of the implementation and the computational time, the Karhunen-Loève expansion is appropriate to represent the weather variables.