Term: Reinforced concrete structures durability
**Service Life Assessment of Reinforced Concrete Structures:**
– Tuutti model for service life assessment
– Variables influencing service life
– Initiation and propagation periods of steel rebar corrosion
– Identification of initiation time and propagation time
– Factors affecting initiation time: carbonation, chlorides
**Corrosion Mechanisms in Reinforced Concrete Structures:**
– Carbonation-induced corrosion:
– Rate of carbonation propagation
– Factors affecting carbonation rate
– Evaluation of initiation time using carbonation coefficient
– Chloride-induced corrosion:
– Localized corrosion due to chlorides
– Factors influencing initiation time
– Transport phenomena of chloride penetration
– Chloride binding in concrete
**Concrete Cover and Corrosion Protection:**
– Concrete cover cracking as a limit state
– Factors affecting corrosion rate: oxygen, water content, humidity
– Steel rebar protection in an alkaline environment
– Importance of maintaining passivation condition
**Durability Design Approaches:**
– Standard approach (EN 206):
– Identification of exposure conditions and degradation process
– Prescriptions for w/c ratio, cement content, cover thickness
– Performance-based approach:
– Real design based on degradation process models
– Consideration of environmental factors as loads
**References and Further Reading:**
– Key references on material degradation, corrosion, and durability
– European projects like DuraCrete and FIB Model Code for Service Life Design
– Concrete degradation and reinforced concrete as related topics.
The durability design of reinforced concrete structures has been recently introduced in national and international regulations. It is required that structures are designed to preserve their characteristics during the service life, avoiding premature failure and the need of extraordinary maintenance and restoration works. Considerable efforts have therefore made in the last decades[when?] in order to define useful models describing the degradation processes affecting reinforced concrete structures, to be used during the design stage in order to assess the material characteristics and the structural layout of the structure.