PSI - Issue 66

Mansi Gupta et al. / Procedia Structural Integrity 66 (2024) 122–134

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Mansi Gupta et al./ Structural Integrity Procedia 00 (2025) 000 – 000

Afterwards, the crack opening analysis is done to understand the pattern of crack opening displacement (COD) with time. Fig. 10 shows the pattern of COD with respect to simulation time. The graph shows a linear increase in COD values with time. Due to computational restrictions, the complete failure of the beam sample has not been achieved in the present study. The present analysis can be extended to get a complete profile of COD for gaining clearer insights on nanoscale fracture. 7. Conclusion The atomic fracture mechanisms of the calcium silicate hydrate gel have been understood from the perspective of molecular dynamics. In the present study, the behaviour of CSH nano-beam under the three-point bending has been analysed under the action of static load. The study sheds light on the crucial role played by atomic bonds on the crack propagation in an edge-cracked CSH sample. The bending behaviour of CSH gel has been successfully simulated using MD. The findings highlight the role of atomic structure on the deformation behaviour. The weak ionic bond between oxygen and hydrogen is majorly responsible for crack widening as compared to the strong covalent network between calcium chains. It can be inferred from atomic positions and velocity profile that the presence of interlayer water in CSH is primarily responsible for failure. The continuous atomic bonding and debonding observed near the notch tip delays the propagation of crack thus, resulting in overall quasibrittle behaviour of concrete. The study shows the competence of MD simulations in successfully capturing the fracture behaviour and shed lights on the phenomena happening at nanoscale. The MD simulations can further be used to study the fracture characteristics of additive concrete mixes under the action of various loads as a future scope of this work. Acknowledgement The authors wish to express their gratitude to the Computer Centre of the National Institute of Technology Rourkela for supplying the high-performance computing facility (HPCF) that was crucial for conducting this molecular dynamics investigation. References 1. Taylor, H. F. (1986). Proposed structure for calcium silicate hydrate gel. Journal of the American Ceramic Society, 69(6), 464-467. 2. Pellenq, R. J. M., Kushima, A., Shahsavari, R., Van Vliet, K. J., Buehler, M. J., Yip, S., & Ulm, F. J. (2009). A realistic molecular model of cement hydrates. Proceedings of the National Academy of Sciences, 106(38), 16102-16107. 3. Hansen-Dörr, A. C., Wilkens, L., Croy, A., Dianat, A., Cuniberti, G., & Kästner, M. (2019). Combined molecular dynamics and phase-field modelling of crack propagation in defective graphene. Computational Materials Science, 163, 117-126. 4. Molaei, F. (2022). Molecular dynamics simulation of edge crack propagation in single crystalline alpha quartz. Journal of Molecular Graphics and Modelling, 111, 108-085. 5. Abhiram, B. R., & Ghosh, D. (2023). Influence of nanofiller agglomeration on fracture properties of polymer nanocomposite: Insights from atomistic simulation. Engineering Fracture Mechanics, 290, 109-503. 6. Duque-Redondo, E., Bonnaud, P. A., & Manzano, H. (2022). A comprehensive review of CSH empirical and computational models, their applications, and practical aspects. Cement and Concrete Research, 156, 106-784. 7. Bahraq, A. A., Al-Osta, M. A., Al-Amoudi, O. S. B., Obot, I. B., Maslehuddin, M., & Saleh, T. A. (2022). Molecular simulation of cement based materials and their properties. Engineering, 15, 165-178. 8. Barbhuiya, S., & Das, B. B. (2023). Molecular dynamics simulation in concrete research: A systematic review of techniques, models and future directions. Journal of Building Engineering, 107-267. 9. Hou, D., Zhu, Y., Lu, Y., & Li, Z. (2014). Mechanical properties of calcium silicate hydrate (C – S – H) at nano-scale: A molecular dynamics study. Materials Chemistry and Physics, 146(3), 503-511. 10. Hou, D., Zhao, T., Wang, P., Li, Z., & Zhang, J. (2014). Molecular dynamics study on the mode I fracture of calcium silicate hydrate under tensile loading. Engineering Fracture Mechanics, 131, 557-569. 11. Bauchy, M., Laubie, H., Qomi, M. A., Hoover, C. G., Ulm, F. J., & Pellenq, R. M. (2015). Fracture toughness of calcium – silicate – hydrate from molecular dynamics simulations. Journal of Non-Crystalline Solids, 419, 58-64. 12. Mohamed, A. K., Parker, S. C., Bowen, P., & Galmarini, S. (2018). An atomistic building block description of CSH-Towards a realistic CSH model. Cement and Concrete Research, 107, 221-235. 13. Liang, Y. (2020). Mechanical and fracture properties of calcium silicate hydrate and calcium hydroxide composite from reactive molecular dynamics simulations. Chemical Physics Letters, 761, 138-117.