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Deterioration Models and Service Life Planning (Part 1). Rak-43.3301 Repair Methods of Structures I (4 cr) Esko Sistonen. MICRO-LEVEL DURABILITY AND LOADING FACTORS. pore size distribution of the cement paste in sandwich-element concrete facade

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deterioration models and service life planning part 1

Deterioration Models and Service Life Planning (Part 1)

Rak-43.3301 Repair Methods of Structures I (4 cr)

Esko Sistonen

micro level durability and loading factors
MICRO-LEVEL DURABILITY AND LOADING FACTORS
  • pore size distribution of the cement paste in sandwich-element concrete facade
  • total air content and protective pore ratio in cement paste
  • water-cement ratio
  • tensile strength of cementpaste, especially in tranzition layer near aggregate stones
  • micro-cracking of concrete due to chemical reactions and crystallizations of materials
  • carbonation rate of different concrete mixtures
  • corrosion rate of reinforcement in carbonated and cracked concrete
  • critical moisture content of concrete for reinforcement corrosion
micro level damage mechanisms
MICRO-LEVEL DAMAGE MECHANISMS
  • correlation between air pore amount, moisture content and freeze-thaw cycle resistance of concrete
  • salt crystallization and its effect on concrete damages
  • chemical reactions in concrete under Finnish climate
  • stresses and cracks due to temperature changes and gradients in conrete
  • changes of pore structure of concrete
  • mathematical evaluation methods of the durability of concrete under Finnish climate
macro level durability and loading factors
MACRO-LEVEL DURABILITY AND LOADING FACTORS
  • moisture distribution of impregnated or coated sandwich-element concrete facade compared with plain concrete facades (due to rain water or heat and moisture transfer)
  • temperature distribution in outer panel of sandwich-facades during the year
  • carbonation rates of impregnated or coated concrete facade
  • chloride content in concrete facades
macro level damage mechanisms
MACRO LEVEL DAMAGE MECHANISMS
  • frost damage mechanisms of concrete in sandwich-facades
  • corrosion mechanisms of reinforcement in sandwich-facades
  • cracking of concrete and stresses between inner and outer panel due to temperature variation and shrinkage
  • strains in facade elements due to temperature gradients
  • chemical and salt problems in Finnish concrete facades
  • effect of different impregnations and coatings to moisture content, carbonation and damages in sandwich-facades
  • service life calculation methods and formulas for sandwich-facades
micro level repair methods
MICRO-LEVEL REPAIR METHODS
  • methods to decrease moisture content and carbonation in concrete (effect on decrease in frost damages and reinforcement corrosion)
  • impregnation of concrete
  • coatings for concrete surface
  • cathodic protection of reinforcements
  • realkalisation of concrete
  • critical chloride content
random variable degradation model in case of a single inspection
Random-Variable Degradation Model in case of a single inspection.

J.M. van Noortwijk, M.D. Pandey, A stochastic deterioration process for

time-dependent reliability analysis

service life of concrete structures a two phase modeling deterioration
Service life of concrete structures – a two-phase modeling deterioration

FIB (CEB-FIP), Bulletin 3 – Structural Concrete – Textbook on behaviour, Design and Performance (Updated knowledge of the CEB/FIP Model Code 1990), Vol. 3, December 1999.

relationship between durability and performance
Relationship between durability and performance

CEB-FIP: Durable of Concrete Structures, Design Guide, T. Thelford, London, 1992.

slide12

Transport mechanisms for aggressivesubstancesinfluence on concrete and reinforcement, and importance of the protective concrete layer – to protect the structure against deterioration

FIB (CEB-FIP), Bulletin 3 – Structural Concrete – Textbook on behaviour, Design and Performance (Updated knowledge of the CEB/FIP Model Code 1990), Vol. 3, December 1999.

slide13

td= γt tg

td = the design service life,

γt = the lifetime safety factor, and

td = the target service life.

slide14

Service life predicted with only mean values and mean values and scatters of the parametersin the prediction models. R(t) and S(t) are expressed with both mean values and scatters. DuraCrete (1999)

slide15

Increase of failureprobabilitythe resistance R of a structure, and of the load effect SFAILURE = R < S; the probability of failure defined as: Pf (t) = P{R(t) < S(t)}

the meaning of lifetime safety factor in a performance problem
The meaning of lifetime safety factor in a performance problem

Durability Design of Concrete Structures- RILEM Report 14:(Ed. A. Sarja and E. Vesikari), Spon, London, 1996. p.155.

the meaning of lifetime safety factor in degradation problem
The meaning of lifetime safety factor in degradation problem

Durability Design of Concrete Structures- RILEM Report 14:(Ed. A. Sarja and E. Vesikari), Spon, London, 1996. p.155.

slide18
Probabilitydensityfunction for strength (fR) and action - load (fS) and failure probability (shaded area)
full probabilistic performance concept
Full-probabilisticperformanceconcept.

Ferreira, R.M. (2004), PROBABILITY-BASED DURABILITY ANALYSIS OF CONCRETE STRUCTURES IN MARINE ENVIRONMENTS

reliability index b
Reliabilityindexb

Relationship of failure probability pf and reliability index β for

a normal distributed reliability function.

Ferreira, R.M. (2004), PROBABILITY-BASED DURABILITY ANALYSIS OF CONCRETE STRUCTURES IN MARINE ENVIRONMENTS