A microstructure-based constitutive model for cement paste with chemical leaching effect

• Published in: Mechanics of materials 2020-11, Vol.150, p.103571, Article 103571
• Main Authors: Shen, W.Q., Shao, J.F., Burlion, N., Liu, Z.B.
• Format: Article
• Language: English
• Subjects: Cement paste; Chemical leaching; Concrete; Dissolution; Engineering Sciences; Homogenization; Porosity
• ISSN: 0167-6636; 1872-7743
• DOI: 10.1016/j.mechmat.2020.103571

This work focuses on the study of macroscopic mechanical behavior of cement paste in relation with micro-structural degradation due to chemical leaching. According to experimental evidences, the degradation of cement paste is mainly characterized by a significant increase of porosity due to the dissolution of Portlandite (CH) and the decalcification of calcium silicate hydrates (C–S–H). We shall first establish the explicit relations between macroscopic elastic properties and plastic yield stresses and porosity of cement paste by using analytical homogenization methods. With these relations, the degradation of elastic and plastic properties of cement paste by chemical leaching can be systematically determined. Combining with a specific plastic hardening law, the complete micro-macro constitutive model is formulated to describe the mechanical behavior of cement paste under general loading conditions. The efficiency of the proposed model is assessed through the comparison between numerical results and experimental data in uniaxial and triaxial compression tests performed on both sound and leached samples. •An analytical plastic criterion is established from rigorous homogenization procedure for porous cement paste.•The analytical plastic criterion explicitly takes into account the effect of porosity on the macroscopic strength.•Based on the analytical criterion, a complete elastic-plastic model is formulated.•The effect of chemical leaching on mechanical response can be taken into account by considering the evolution of porosity.•The efficiency of the proposed model is verified through experimental data.