Service life of RC structures: chloride induced corrosion: prescriptive versus performance-based methodologies

Reinforced concrete (RC) structures subjected to aggressive environmental exposure conditions are traditionally designed to satisfy safety, serviceability, durability and aesthetics requirements throughout their operational design service life. This is usually established using time-dependent mathematical models, developed through performance-based methodologies in guidelines and European and national standards. However, at present, in most cases, prescriptive methodologies are used. The objective of this paper is to compare, as regards chloride induced corrosion, defined target periods of service life according to a prescriptive methodology with service life results of a performance-based methodology. In the laboratory concrete specimens were manufactured having compositions according to a prescriptive specification. These specimens were tested in order to determine their performance properties (strength, chloride diffusion and capillary absorption). Test results were included in the mathematical models of the performance-based specifications. The classic safety factor and recent probabilistic approaches have been used to estimate the service life of each composition being compared to the target periods defined in the prescriptive specification. Numerical calculations show that the results of the Partial Safety Factor and a full probabilistic approach are distinctly different and consequently their convergence still needs to be improved, due to the complexity of the process of chloride penetration into the concrete, not only the model but also the input values. When compared to performance-based approaches it would be expected that the prescriptive methodology would be more conservative due to its less quantified information on concrete and environment properties, though in this study this was not always true.

[1]  G. Glass,et al.  The presentation of the chloride threshold level for corrosion of steel in concrete , 1997 .

[2]  Geoffrey Mays,et al.  Durability of Concrete Structures : Investigation, repair, protection , 1990 .

[3]  K. Tuutti.  Corrosion of steel in concrete , 1982 .

[4]  Arnon Bentur,et al.  Steel corrosion in concrete , 1997 .

[5]  Julio Appleton,et al.  CASE STUDIES OF CONCRETE DETERIORATION IN A MARINE ENVIRONMENT IN PORTUGAL , 2002 .

[6]  Jan Bijen.  Durability of engineering structures , 2003 .

[7]  A W Beeby,et al.  CONCISE EUROCODE FOR THE DESIGN OF CONCRETE BUILDINGS. BASED ON BSI PUBLICATION DD ENV 1992-1-1: 1992. EUROCODE 2: DESIGN OF CONCRETE STRUCTURES. PART 1: GENERAL RULES AND RULES FOR BUILDINGS , 1993 .

[8]  Michael Yit Lin Chew,et al.  Integration of durability with structural design: An optimal life cycle cost based design procedure for reinforced concrete structures , 2009 .

[9]  Radomir Folić.  Durability design of concrete structures, Part 1: Analysis fundamentals , 2009 .

[10]  Michael Havbro Faber,et al.  fib Bulletin 34. Model Code for Service Life Design , 2006 .

[11]  Said Jalali,et al.  Probability-based durability analysis of concrete structures in marine environment , 2004 .

[12]  G. Sawade,et al.  6 – Degradation of prestressed concrete , 2007 .

[13]  Cruz Alonso,et al.  Cover cracking as a function of bar corrosion: Part I-Experimental test , 1993 .

[14]  Odd E. Gjørv,et al.  Durability design of concrete structures in severe environments , 2014 .

[15]  Luca Bertolini,et al.  Chloride threshold for rebar corrosion in concrete with addition of silica fume , 2008 .

[16]  G J. Frohnsdorff,et al.  Service-Life Modeling and Design of Concrete Structures for Durability , 2004 .

[17]  Arthur H. Nilson,et al.  Design of concrete structures , 1972 .

[18]  Patrick Dangla,et al.  Assessment and prediction of RC structure service life by means of durability indicators and physical/chemical models , 2009 .

[19]  Dimitri V. Val,et al.  Probabilistic evaluation of initiation time of chloride-induced corrosion , 2008, Reliab. Eng. Syst. Saf..