**Commenced**in January 2007

**Frequency:**Monthly

**Edition:**International

**Paper Count:**32017

##### Prediction of Time to Crack Reinforced Concrete by Chloride Induced Corrosion

**Authors:**
Anuruddha Jayasuriya,
Thanakorn Pheeraphan

**Abstract:**

In this paper, a review of different mathematical models which can be used as prediction tools to assess the time to crack reinforced concrete (RC) due to corrosion is investigated. This investigation leads to an experimental study to validate a selected prediction model. Most of these mathematical models depend upon the mechanical behaviors, chemical behaviors, electrochemical behaviors or geometric aspects of the RC members during a corrosion process. The experimental program is designed to verify the accuracy of a well-selected mathematical model from a rigorous literature study. Fundamentally, the experimental program exemplifies both one-dimensional chloride diffusion using RC squared slab elements of 500 mm by 500 mm and two-dimensional chloride diffusion using RC squared column elements of 225 mm by 225 mm by 500 mm. Each set consists of three water-to-cement ratios (w/c); 0.4, 0.5, 0.6 and two cover depths; 25 mm and 50 mm. 12 mm bars are used for column elements and 16 mm bars are used for slab elements. All the samples are subjected to accelerated chloride corrosion in a chloride bath of 5% (w/w) sodium chloride (NaCl) solution. Based on a pre-screening of different models, it is clear that the well-selected mathematical model had included mechanical properties, chemical and electrochemical properties, nature of corrosion whether it is accelerated or natural, and the amount of porous area that rust products can accommodate before exerting expansive pressure on the surrounding concrete. The experimental results have shown that the selected model for both one-dimensional and two-dimensional chloride diffusion had ±20% and ±10% respective accuracies compared to the experimental output. The half-cell potential readings are also used to see the corrosion probability, and experimental results have shown that the mass loss is proportional to the negative half-cell potential readings that are obtained. Additionally, a statistical analysis is carried out in order to determine the most influential factor that affects the time to corrode the reinforcement in the concrete due to chloride diffusion. The factors considered for this analysis are w/c, bar diameter, and cover depth. The analysis is accomplished by using Minitab statistical software, and it showed that cover depth is the significant effect on the time to crack the concrete from chloride induced corrosion than other factors considered. Thus, the time predictions can be illustrated through the selected mathematical model as it covers a wide range of factors affecting the corrosion process, and it can be used to predetermine the durability concern of RC structures that are vulnerable to chloride exposure. And eventually, it is further concluded that cover thickness plays a vital role in durability in terms of chloride diffusion.

**Keywords:**
Accelerated corrosion,
chloride diffusion,
corrosion cracks,
passivation layer,
reinforcement corrosion.

**Digital Object Identifier (DOI):**
doi.org/10.5281/zenodo.1132028

**References:**

[1] A. Abou-Zeid, J.H. Allen, J.P. Barlow, K. Carlson, G.T. Halvorsen, M.N. Hassoun, P. Hedli, T.C. Liu, Control of Cracking in Concrete Structures, 2001.

[2] S. A. Alghamdi, S. Ahmad, Service Life Prediction of RC Structures Based on Correlation between Electrochemical and Gravimetric Reinforcement Corrosion Rates, Cem. Concr. Compos. (2013) 64–68.

[3] C. Alonso, C. Andrade, J. Rodreguez, J. Diez, Factors Controlling Cracking of Concrete Affected by Reinforcement Corrosion, Mater. Struct. (1998) 435–441.

[4] Z. Bažant, L. Estenssoro, Surface Singularity and Crack Propagation. International Journal of Solids and Structures, Int. J. Solids Struct. (1979) 405–426.

[5] H. J. Dagher, S. Kulendran, Finite Element Modeling of Corrosion Damage in Concrete Structures, ACI Struct. J. (1992) 699–708.

[6] T. Hoar, The Production and Breakdown of the Passivity of Metals, Corros. Sci. (1967) 341–355.

[7] M. Ja, Kolotyrkin, Effects on Anions on the Dissolution Kinetics of Metals, J. Electrochem. Soc. (1961) 209–216.

[8] A. Jamali, U. Angst, B. Adey, B. Elsener, Modeling of Corrosion-Induced Concrete Cover Cracking, Constr. Build. Mater. (2013) 225–237.

[9] M. Lacasse, D. Vanier, Durability of Building Materials and Components, Duracrete. (1999) 1343–1356.

[10] H. P. Leckie, H. Uhlig, Environmental Factors Affecting the Critical Potential for Pitting in 18-8 Stainless Steel, J. Electrochem. Soc. (1966) 1262–1267.

[11] L. F. Lin, C. Y. Chao, D. D. Macdonald, A Point Defect Model for Anodic Passive Films - II, J. Electrochem. Soc. (1981) 1194–1198.

[12] Y. Liu, Modeling the Time to Corrosion Cracking of the Cover Concrete in Chloride Contaminated Reinforced Concrete Structures, Blacksburg, VA, 1996.

[13] Y. Liu, R. Weyers, Modeling the Time to Corrosion Cracking of the Cover Concrete in Chloride Contaminated Reinforced Concrete Structures, Blacksburg, VA, 1998.

[14] C. Lu, W. Jin, R. Liu, Reinforcement Corrosion-Induced Cover Cracking and its Time Prediction for Reinforced Concrete Structures, Corros. Sci. (2011) 1337–1347.

[15] Q. Lv, R. Zhu, Model for Forcasting the Time of Corrosion-Induced Reinforced Concrete Cracking, in: Int. Conf. Performance-Based Life-Cycle Struct. Eng., Brisbane Convention and Exhibition Centre, Brisbane, Australia, 2015: p. ID210.

[16] T. Maaddawy, K. Soudhki, A Model for Prediction of Time from Corrosion Initiation to Corrosion Cracking, Cem. Concr. Compos. (2007) 168–175.

[17] P. McGrath, R. Hooton, Effect of Binder Composition on Chloride Penetration Resistance of Concrete, in: American Concrete Institute, Detroit, MI, 1997.

[18] P. K. Mehta, No Title, in: S. W. Tonini, D. E., Dean (Ed.), Eff. Cem. Compos. Corros. Reinf. Steel Concr., ASTM, Baltimore, MD, 1977: pp. 12–19.

[19] F. J. Molina, C. Alonso, C. Andrade, Cover Cracking as a Function of Rebar Corrosion: Part 2 - Numerical Model, Mater. Struct. (1993) 532–548.

[20] S. Morinaga, Prediction of Service Lives of Reinforced Concrete Buildings based on Rate of Corrosion in Reinforcing Steel, (1988).

[21] S. Morinaga, Prediction of service lives of reinforced concrete buildings based on corrosion rate of reinforcing steel, in: Proc. Fifth Int. Conf. Durab. Build. Mater. Components, E. & F.N. SPON, London, UK, 1990: pp. 5–16.

[22] A. Muñoz, C. Andrade, Reinforced Concrete Cover Cracking due to the Pressure of Corrosion Products, Adv. Constr. Mater. (2007).

[23] N. Sato, Anodic Breakdown of Passive Films on Metals, J. Electrochem. Soc. (1982) 255–260.

[24] R. Tepfers, Cracking of Concrete Cover along Anchored Deformed Reinforcing Bars, Mag. Concr. Res. (1979) 3–12.

[25] P. Thoft-Christensen, Stochastic modelling of the crack initiation time for reinforced concrete structures, ASCE Struct. Congr. (2000) 8.

[26] K. Tuutti, Corrosion of Steel in Concrete, Swedish Cement and Concrete Research Institute, 1982.

[27] K. Yokozeki, K. Motohashi, K. Okada, T. Tsutsumi, A Rational Model to Predict the Service Life of RC Structures in Marine Environment, ACI. (1997) 777–799.

[28] Y. Zhao, W. Jin, Modeling the Amount of Steel Corrosion at the Cracking of Concrete Cover, Adv. Struct. Eng. (2006) 687–696.

[29] ASTM C876 Standard Test Method for Half-Cell Potentials of Uncoated Reinforcing Steel in Concrete, (1999).

[30] ASTM G1 Standard practice for preparing, cleaning, and evaluation corrosion test specimens under chemical cleaning method, 1999.