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

„Performance-Based“ approach „Prescriptive“ or „Deemed to satisfy“ approach versus „Performance-Based“ approach ISO 13823 General Principles on the Design of Structures for Durability (2008) ISO 16204 Durability – Service life design of concrete structures (2012) fib Model Code 2010 (2012)

„Performance-Based“ approach „Prescriptive“ or „Deemed to satisfy“ approach versus „Performance-Based“ approach ISO 13823 General Principles on the Design of Structures for Durability (2008) ISO 16204 Durability – Service life design of concrete structures (2012) fib Model Code 2010 (2012)

„Performance-Based“ approach „Prescriptive“ or „Deemed to satisfy“ approach versus „Performance-Based“ approach ISO 13823 General Principles on the Design of Structures for Durability (2008) ISO 16204 Durability – Service life design of concrete structures (2012) fib Model Code 2010 (2012)

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

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

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

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

Values of k - factor

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

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

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

http://www.freet.cz

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

FREET - Feasible Reliability Engineering Tool Spolehlivost – Degradace - Životnost

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

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