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Lattice modeling of cover cracking due to reinforcement corrosion
Branko Šavija, Mladena Luković, Erik Schlangen
Lattice modeling of cover cracking due to reinforcement corrosion
Consec13, Nanjing
Content:
•Aim of the research
•Lattice model
•Corrosion induced cracking
•Conclusions
Lattice modeling of cover cracking due to reinforcement corrosion
Consec13, Nanjing
Why study corrosion induced cracking?
• Corrosion of reinforcement causes:(1)Loss of steel cross-section(2)Loss of bond between steel and concrete(3)Change in ductility of steel (more brittle)(4)Change in failure mode for beams (from shear to
bond failure)Serious problems preceded bycracking of the concrete cover!
Lattice modeling of cover cracking due to reinforcement corrosion
Consec13, Nanjing
Research goal:
• Model corrosion induced cracking using Delft lattice model
• Study the influence of concrete meso-structure on the cracking
• Study the influence of stress-release mechanisms
• Study the influence of pitting corrosion
Lattice modeling of cover cracking due to reinforcement corrosion
Consec13, Nanjing
Content:
•Aim of the research
•Lattice model
•Corrosion induced cracking
•Conclusions
Lattice modeling of cover cracking due to reinforcement corrosion
Consec13, Nanjing
Lattice models in fracture mechanics
Modelling of concrete fracture- set of beam/truss elements!
(Schlangen (1993)) (Schlangen & Qian (2009))
(Schlangen and Garboczi (1997))
Lattice modeling of cover cracking due to reinforcement corrosion
Consec13, Nanjing
Lattice models in fracture mechanics
Some uses of the model:
ASR (Anaç et al.) Autogeneous shrinkage (Luković et al.)
Lattice modeling of cover cracking due to reinforcement corrosion
Consec13, Nanjing
Content:
•Aim of the research
•Lattice models
•Corrosion induced cracking
•Conclusions
Lattice modeling of cover cracking due to reinforcement corrosion
Consec13, Nanjing
Corrosion induced cracking
• Corrosion products “migrate” into pores around the steel and open cracks
• Needs to be taken into account in the model!
Lattice modeling of cover cracking due to reinforcement corrosion
Consec13, Nanjing
Uniform corrosion:
The pressure is a function of:•Bar radius•Steel loss•Migration of corrosion products•Corrosion product density•Young modulus of corrosion products
Not precisely quantified!
Cracking pressure is a function:•Rebar position•Concrete (local) mechanical properties
Lattice modeling of cover cracking due to reinforcement corrosion
Consec13, Nanjing
Uniform corrosion
Concrete as a heterogeneous materialAnm material model (Qian 2012)
Andrade et al. (1993)
Lattice modeling of cover cracking due to reinforcement corrosion
Consec13, Nanjing
Uniform corrosion
Influence of the porous zone (PZ) existence on the cracking time (geometry 1)
Influence of the penetration of rust into open cracks (geometry 1)
Delays the onset of damage!
Influences crack propagation kinetics!
Lattice modeling of cover cracking due to reinforcement corrosion
Consec13, Nanjing
Uniform corrosion
Lattice modeling of cover cracking due to reinforcement corrosion
Consec13, Nanjing
Pitting corrosion
• Caused by Cl penetration• Non-uniform pressure
exerted• Different cracking
behaviouor
Jang and Oh (2010)
Lattice modeling of cover cracking due to reinforcement corrosion
Consec13, Nanjing
Pitting corrosion
4 8 Uniform
More: Šavija et al. (2013), Constr Build Mater 44, pp.626-638
Lattice modeling of cover cracking due to reinforcement corrosion
Consec13, Nanjing
Content:
•Aim of the research
•Lattice models
•Corrosion induced cracking
•Conclusions
Lattice modeling of cover cracking due to reinforcement corrosion
Consec13, Nanjing
Conclusions• Corrosion induced cracking can be simulated
using the Delft lattice model• Cracking patterns are influenced by concrete
material structure• Crack initiation is influenced by the porous
layer around the steel• Crack propagation is influenced by penetration
of corrosion products into open cracks• Pitting corrosion causes more large cracks
compared to uniform corrosionExperiments to study the porous layer, corrosion product migration, and rust properties are being performed by many researchers!
Lattice modeling of cover cracking due to reinforcement corrosion
Consec13, Nanjing
See our latest results at: http://microlab-m3c4.blogspot.com/Contact: [email protected]
Thank You very much for Your attention!
