Interfacial fracture behaviour between cement paste and epoxy coating - An experimental and phase-field approach

  • Pratik Gujar Department of Applied Mechanics, Indian Institute of Technology Madras India
  • Hirshikesh Department of Applied Mechanics, Indian Institute of Technology Madras, India
  • Manu Santhanam Department of Civil Engineering, Indian Institute of Technology Madras, India
  • Ratna Kumar Annabattula Department of Mechanical Engineering, Indian Institute of Technology Madras, India
  • Pijush Ghosh Department of Applied Mechanics, Indian Institute of Technology Madras, India
Keywords: Epoxy coated cement paste, Pull-off adhesion test, Interface fracture, Phase-field method

Abstract

Surface coatings are mainly applied to protect concrete structures against various environmental conditions. However, the interface between the concrete and coating is a weak link, and interfacial delamination is the primary mode of failure. Fracture resistance is the main design criteria for these materials, and therefore, it is necessary to investigate possible causes of interfacial failure for preventive measures. To this end, we have investigated the potential failure mechanisms and measured interfacial strength by performing a pull-off adhesion test on epoxy coated cement paste. From the pull-off adhesion test, adhesive (interface) failure between cement paste and epoxy is predominantly observed. It is observed that the adhesive (interfacial) strength for the sample tested on 50th day is more than the 28 days hydrated sample. This is due to additional curing of cement paste samples after coating epoxy which leads to higher interfacial strength. We also present the phase-field model (PFM) to predict the adhesive failure for this system. The results obtained from the PFM, i.e., load at failure and crack path are validated against experimental results. Finally, the influence of various material parameters such as elastic modulus and fracture energy of the interface on interfacial fracture behaviour is studied.

Published
2021-02-11
How to Cite
Gujar, P., Hirshikesh, Santhanam, M., Annabattula, R. K. and Ghosh, P. (2021) “Interfacial fracture behaviour between cement paste and epoxy coating - An experimental and phase-field approach”, RILEM Technical Letters, 50, pp. 186-193. doi: 10.21809/rilemtechlett.2020.133.
Section
Articles