When a reinforced structure is exposed to marine environments, chloride-induced corrosion occurs and it decreases the durability and performance of the structure. The degree of humidity, the presence of cracks, environmental conditions, w/c ratio, and cement content are the influencing factors for chloride ion ingress into concrete. All of them, w/c ratio and cement content are treated as the most crucial factors on diffusion. This paper focus on Molecular Dynamics (MD) simulation method to determine the diffusion coefficient of chloride ion in concrete. The effect of w/c ratio and cement content on the diffusivity of chloride ion is also evaluated. The diffusion coefficients are obtained 2.88x10-12 m2/s, 3.13x10-12 m2/s, and 3.61x10-12 m2/s respectively for different w/c ratio of 0.40, 0.45 and 0.50 with constant cement content. Again the diffusion coefficient are calculated 4.6x10-12 m2/s, 3.13x10-12 m2/s, 2.78x10-12 m2/s respectively for different cement content of 300 kg/m3, 350 kg/m3 and 400 kg/m3 with constant w/c ratio. The simulation results clearly indicate that the diffusion coefficient of chlorine was affected by w/c ratio and cement content significantly.
Al-Gadhib AH (2010). Numerical simulation of chloride diffusion in RC structures and the implications of chloride binding capacities and concrete mix. International Journal of Civil & Environmental Engineering, 10(5), 19-28.
Al-matar A, Tobgy AH, Al-Faiad MA (2012). Self diffusion coefficient of Lennard-Jones fluid using temperature dependent interaction parameters at different pressures. Sixth Jordan International Chemical Engineering Conference, Amman, Jordan.
Erdoǧdu Ş, Kondratova IL, Bremner TW (2004). Determination of chloride diffusion coefficient of concrete using open-circuit potential measurements. Cement and Concrete Research, 34, 603- 609.
Hirschfelder JO, Curtiss CF, Bird RB (1964). Molecular Theory of Gases and Liquids. John Wiley and Sons, New York.
Li LY, Easterbrook D, Xia J, Jin WL (2015). Numerical simulation of chloride penetration in concrete in rapid chloride migration. Cement and Concrete Composites, 63, 113-121.
Nissen T (2016). Chloride Ingress in Concrete. Ph.D thesis, Norwegian University of Science and Technology, Gjøvik, Norway.
Rapaport DC (2004). The Art of Molecular Dynamics Simulation, (2nd edition). Cambridge University Press, New York.
Townsend HE, Cleary HJ, Allegra L (1981). Breakdown of oxide films in steel exposure to chloride solutions. NACE Corrosion, 37, 384-391.
Wachira JM (2019). Effects of chlorides on corrosion of simulated reinforced blended cement mortars. International Journal of Corrosion, 2019, Article ID 2123547.
Wang Y, Li LY, Page CL (2005). Modelling of chloride ingress into concrete from a saline environment. Building and Environment, 40(12), 1573-1582.
Xiuli Du, Liu Jin, Guowei Ma (2014). A meso-scale numerical method for the simulation of chloride diffusivity in concrete. Finite Elements in Analysis and Design, 85, 87-100.