Global Sensitivity Analysis for the Polymeric Microcapsules in Self-Healing Cementitious Composites.

Area of Science:

• Materials Science
• Civil Engineering
• Computational Mechanics

Background:

• Self-healing cementitious composites utilize microencapsulated healing agents for enhanced durability.
• Microcapsules, while enabling self-healing, reduce the composite's elastic properties prior to healing.
• Micromechanical models are used to evaluate these property reductions but are complex and parameter-sensitive.

Purpose of the Study:

• To propose a micromechanical model for evaluating effective properties of cementitious composites containing microcapsules.
• To apply quantitative global sensitivity analysis to identify critical parameters influencing model accuracy.
• To determine which parameters require further investigation for improved confidence in predictive results.

Main Methods:

• Development of a micromechanical model to assess the effective properties of microcapsule-reinforced cementitious materials.
• Application of the Extended Fourier Amplitude Sensitivity Test (EFAST) for quantitative global sensitivity analysis.
• Computation of first-order sensitivity indices to rank parameter importance.

Main Results:

• The volume fraction of microcapsules was identified as the most influential parameter on the effective elastic properties before self-healing.
• The sensitivity analysis highlighted the significant, non-negligible influence of interfacial properties between microcapsules and the matrix.
• Parameter importance was quantified, guiding future research efforts.

Conclusions:

• The study successfully identified key parameters governing the effective properties of microcapsule-containing cementitious composites.
• Accurate micromechanical modeling of these materials necessitates a thorough understanding of microcapsule volume fraction and interfacial characteristics.
• This research provides a foundation for optimizing the design and performance of self-healing cementitious materials.