1. Probabilistic modelling and the k-value concept
B.Teplý, M.Chromá, P.Rovnaníková – BUT Brno
A. Strauss – BOKU Wien
Structural and physical Aspects of CivEng

2. „Performance-Based“ approach
„Prescriptive“ or „Deemed to satisfy“ approach
versus
„Performance-Based“ approach
ISO General Principles on the Design of Structures for Durability (2008)
ISO Durability – Service life design of concrete structures (2012)
fib Model Code 2010 (2012)

3. „Performance-Based“ approach
„Prescriptive“ or „Deemed to satisfy“ approach
versus
„Performance-Based“ approach
ISO General Principles on the Design of Structures for Durability (2008)
ISO Durability – Service life design of concrete structures (2012)
fib Model Code 2010 (2012)

4. „Performance-Based“ approach
„Prescriptive“ or „Deemed to satisfy“ approach
versus
„Performance-Based“ approach
ISO General Principles on the Design of Structures for Durability (2008)
ISO Durability – Service life design of concrete structures (2012)
fib Model Code 2010 (2012)

5. Specification of Concrete
Fpr EN 206: Concrete – Specification, performance, production and conformity, 2013
Design or Assessment of Concrete Structures
EN 1992 Eurocode 2: Design of concrete
structures, 2004

6. Performance characteristics:
Operational functionality,
….,
Durability (service life),
Reliability (probability of failure, reliability index)

7. Durability: Concretes made with supplementary cementitious materials (SCM)
Prescriptive approach:
limiting values for composition: minim.cem.content,
max (w/c)eff , … k-value concept:
(w/c)eff = water/(cement + k × SCM)
Performance-Based:
Equivalent Concrete Performance Concept,
Equivalent Performance of Combination Concept and
Modeling

8. Durability: Concretes made with supplementary cementitious materials (SCM)
Prescriptive approach:
limiting values for composition: minim.cem.content,
max (w/c)eff , … k-value concept:
(w/c)eff = water/(cement + k × SCM)
Performance-Based:
Equivalent Concrete Performance Concept,
Equivalent Performance of Combination Concept and
Modeling

9. Values of k - factor

10. Limit states – differentiation of reliability
ULS = Ultimate Limit State
SLS = Serviceability Limit State
DLS = Durability Limit State
b ··· 50 years reference period (EN 1990)

11. Carbonation Experiment – Jiang et al. (2000)
Modeling: a) Papadakis (2000), k = 0.2, 0.4, 0.5
b) Jiang et al. (2000)

12. Durability limit state – reinforcement depassivation
a … carbonation depth
xc … cover

14. FReET-D - degradation models:
Carbonation
Chloride ingress
Corrosion of reinforcement
Frost attack on concrete
Acide attack
Sulphate attack (in concrete sewer collection systems)
32 models

15. FREET - Feasible Reliability Engineering Tool
Spolehlivost – Degradace - Životnost

16. Carbonation of concrete – comparison and evaluation of models.
Cooling tower:
height of 206 m
in-site investigation at the age of 19.1 years
the depth of carbonation measured at 75 locations (on both the internal and external surfaces)
four models applied
Now, I would like to present a comparison of several models and test data for one example structure:
Structural and physical Aspects of CivEng

17. Carbonation depth (19.1 years) External surface (RH = 70%)
Internal surface
(RH = 93%)
Mean [mm]
COV [%]
Model a
10.8 48
4.4 60
Model b
8.2 24
1.9 43
Model c
12.7 18
8.3 51
Model d
11.9 21
7.7 53
In situ measurements
14.9 56
8.0 29